,,specifications ,,for ,,street ,,roadway ,,pavements ,mc,graw-,hill ,book ,company ,publishers of ,books for ,electrical ,world ,engineering ,record ,railway ,age ,gazette ,signal ,engineer ,electric ,railway ,journal ,metallurgical and ,chemical ,engineering ,the ,engineering and ,mining ,journal ,engineering ,news ,american ,machinist ,american ,engineer ,coal ,age ,power ,,specifications ,,for ,,street ,,roadway ,,pavements ,,with ,,instructions ,,to ,,inspectors ,,on ,,street ,,paving ,,work ,,by ,s4 ,,whinery ,,member ,,american ,,society ,,of ,,civil ,,engineers ,,second ,,edition ,,revised1 ,,enlarged ,,and ,,entirely ,,reset ,mc,g,r,a,w-,,hill ,,book ,,company #bci ,,west #ci,,th ,,street1 ,,new ,,york #f ,,bouverie ,,street1 ,,london1 ,e4 ,c4 #aiac ,,copyright1 #aiac1 ,,by ,,the ,,mcgraw-,,hill ,,book ,,company ,,the,,maple,,press,,york,,pa ,,preface ,,to ,,second ,,edition ,in offering to the public a new edition of 8,specifications for ,street ,roadway ,pavements0 the author has taken advantage of the opportunity to revise and expand somewhat the matter in the original edition and to add thereto ,instructions for ,inspectors on pavement work4 ,since the publication of the original pamphlet in #aijg no little advance has been made in the design and construction of street pavements and the framing of specifications for that work4 ,aside from the personal study and efforts of individual engineers1 the ,association for ,standardizing ,paving ,specifications1 organized in the latter part of #aiji1 has held four important conventions1 devoted to the improvement and standardization of specifications for street pavements1 and its able standing ,committees have devoted much time and thought to the subject4 ,the ,american ,society of ,municipal ,improvements has also devoted much attention to the subject and has adopted standard specifications for most of the common kinds of pavement4 ,other organizations have been working along the same lines4 ,under these circumstances it might be thought that there is no longer any pressing need for the continuance of individual efforts in this field1 and it has been with some hesitation that the author has returned to it4 ,without venturing to criticise the work done by these public organizations it has seemed to the author that there is yet room for individual work in this field1 if for no other reason than that there still remain quite divergent views not only as to the substance1 but as to the form1 scope and phraseology of specifications1 and contributions based upon some knowledge and experience in street pavement may not be without value in reaching final conclusions4 ,as might be expected experience and observation during the past five years have1 in a number of particulars1 modified the author's opinions and shown where the original specifications offered might be improved and enlarged1 so that while1 in the main1 those now offered follow the original text1 the reader will find not a few changes4 ,there has also been added specifications for two comparatively new kinds of roadway pavement that have merited attention1 and for concrete sidewalk and concrete combined curb and gutter4 ,so far as the author is aware there has not been printed1 in ,america at least1 any complete and comprehensive code of instructions for pavement inspectors1 though there appears to be a demand1 as there certainly is a need1 for something of the kind4 ,having been asked about a year since to prepare such a set of instructions for the use of one ,american city1 the author has rewritten parts of them in a more general form1 and they are printed 7with the permission of the engineer for whom they were written7 as ,part ,,ii of this edition4 ,while they would need some revision and modification to meet the conditions and special specification provisions in any particular city1 it is thought they may be useful in at least suggesting the points to be covered4 ,,contents ,,part ,i ,,specifications ,introductory ,,page ,value of general specifications #a ,theory of specifications #a ,street paving work #b ,specifications should be fair and just to contractor #d ,relations of contractor to municipality #f ,advertisements for proposals #g ,instructions to bidders #i ,relation between specifications and contract #i ,specifications #i ,preparation of specifications #i ,engineer as arbiter #aa ,itemized unit prices #ab ,,specifications ,general ,,page ,,section ,general description of work #ac ,definitions #ad #a ,changes in plans and specifications #ae #c ,quality of material and work #ae #d ,inspection #ae #e ,injury to persons and property #af #f ,sanitary and public convenience #af #g-i ,disorderly employees #ag #aj ,order and progress of work #ag #aa ,pavement datum #ah #ab ,city monuments and stakes #ah #ac ,old and new material #ah #ad-ae ,adjusting street structures #ah #af ,connection with existing pavements #ai #ah ,measurements and computations #bj #ba ,incidental and extra work #bj #bc-bd ,guaranty #ba #be ,preparing the sub-grade #bb #bf ,foundations ,concrete foundations--,portland cement #bd #bh-bi ,sand #bf #cj ,stone #bf #ca ,care of materials #bg #cc ,ratios #bg #cd ,mixing ,concrete #bh #ce ,placing concrete #bi #cf ,setting of concrete #bi #cg ,foundation of old paving stone #cj #ci ,foundation of broken stone #ca #dj-da ,sheet asphalt pavement ,general note #cc ,crude and refined asphalts #cf #dc-df ,tempering agent #ch #dg ,sand #ch #dh ,pulverized stone #ci #di ,asphaltic paving cement #ci #ej ,composition1 surface mixture #dj #ea ,base course #db #eb-ed ,laying asphalt pavement #db #ee-eh ,plant #de #ei ,asphalt block pavement ,sub-grade and foundation #df #fj-fa ,asphalt block #df #fb ,composition and quality #df #fc-fd ,laying blocks #dh #ff ,granite block pavement ,granite blocks #ej #ga ,sand cushion #ea #gb ,setting blocks #ea #gc-gd ,filling joints #eb #ge ,bridge and crossing stone #ee #gi ,brick pavement ,sub-grade and foundation #ef #hj-ha ,paving brick #ef #hb-hd ,delivering brick #eh #he ,sand cushion #eh #hf ,setting the brick #ei #hg-hi ,filling the joints #fj #ij ,wood-block pavement ,sub-grade and foundation #fb #ib-ic ,wood-blocks #fc #id ,creosote oil #fe #ie ,preservative treatment #fe #if ,laying wood-blocks #ff #ig ,filling joints #fh #ih ,inspection #fh #ii ,expansion joints #fh #aja ,bituminous concrete pavement ,general note #fi ,sub-grade and foundation #gj #ajc-aji ,bituminous concrete #ga #aaj ,mixing and laying #gc #aaa-aab ,hydraulic concrete pavement ,sub-grade and foundation #gc #aac ,bottom course #gd #aae ,top1 or surface1 course #gd #aaf-abj ,expansion joints #gf #aba ,bituminous surface #gg #abb ,experimental or ,untried ,pavements #gh #abc-abf ,concrete ,curb and ,gutter ,general #hj #abg ,excavation and drainage #ha #abh-abi ,concrete #ha #acj ,weather #hb #acb ,expansion joints #hb #acc ,circular corners #hc #acd ,steel protection #hc #ace ,finishing1 forms1 etc4 #hc #acf-ach ,payment for #hd #aci ,concrete ,sidewalks ,general note #hd ,general dimensions #hd #adj ,grading #he #ada ,drainage #he #adb-adc ,bottom course #hf #add ,surface course #hf #ade ,expansion joints #hg #adg ,weather #hh #adi ,regrading #hh #aej ,repairing defects #hh #aea ,measurement and payment #hh #aeb ,,part ,,ii ,,instructions ,,to ,,inspectors ,introductory note #ia ,general remarks1 inspection and inspectors #ia ,general instructions #id #a-ac ,sub-foundation work general #if #ad curbing #ig #ae rough grading #ih #af fine grading #ih #ag incidental work #ih #ah concrete foundation #ih #ai quality of materials #ih #bj storing materials #ii #ba proportioning #ii #bb mixing concrete #ajj #bc placing concrete #ajj #bd-be ,old paving stone foundation #aja #bf ,broken stone foundation #aja #bg ,sheet asphalt pavement #aja #bh inspecting at paving plant #ajb #bi-cj sand #ajb #ca-cc refined asphalt and flux #ajc #cd-cf asphaltic cement #ajc #cg ratio1 sand and cement #ajd #ch mixing #ajd #ci records #ajd #dj ,inspecting on the street #aje #da-db temperature of mixture #aje #dc preparing street surface #aje #dd laying binder-course #ajf #de laying surface-course #ajf #df-ej ,asphalt block pavement #ajg #ea-eb ,granite block pavement #ajh #ec blocks #ajh #ed sand cushion #ajh #ee setting the block #ajh #ef ramming the blocks #aji #eg filling joints #aaj #eh ,brick pavement #aaj inspecting the brick #aaj #fj sand cushion #aaa #fa setting brick #aaa #fb rolling #aaa #fc filling the joints #aab #fd-fe ,wood-block pavement #aab inspection of blocks #aab #fg mortar bed #aab #fh setting blocks #aac #fi filling the joints #aac #gj ,bituminous concrete pavement #aac #ga-gb ,hydraulic concrete pavement #aac #gc foundation #aac #gd surface-course #aad #ge-gg expansion joints #aad #gh care of work #aad #gi ,concrete combined curb and gutter #aad concrete #aae #ha removing forms #aae #hb corner protection #aae #hc patching #aaf #hd ,hydraulic concrete sidewalk #aaf materials #aaf #hf drainage #aaf #hg two-course work #aaf #hh finishing surface #aaf #hi-ij ,,part ,i ,,specifications ,,for ,,street ,,roadway ,,pavements ,,introductory ,in addition to their value as memoranda and aids in preparing specifications for a particular project1 carefully prepared general specifications1 embodying the latest approved practice1 sometimes supply the most useful and acceptable brief treatises upon any particular branch of engineering work4 ,it has been partly with this thought in mind that the following set of specifications for standard street pavements has been prepared and is now offered to city engineers and municipal authorities4 ,to widen their range and increase their usefulness1 copious foot notes have been added1 referring to alternative requirements and methods of construction1 and giving some of the reasons for the preference or adoption of the construction called for in the specifications4 ,it is recognized that in a good many matters of detail embraced in these specifications there is difference of opinion among able engineers1 many of whom are at least as competent as the writer to determine what is best4 ,they are not offered in a dogmatic spirit1 or with the hope that all the provisions found therein will be accepted4 ,if they shall be of some assistance in bringing about correct standards for such specifications1 their preparation will have been justified4 ,theoretically1 three general classes of engineering specifications may be noted4 ,in the first1 the aim of the engineer is to specify the end or result that it is desired to secure1 leaving the contractor free to originate and follow the methods by which these results are to be attained4 ,in the second the engineer aims to secure the desired end by specifying in detail the materials and the methods which in his opinion will accomplish the purpose1 he himself assuming responsibility for the results4 ,either of these two classes of specifications is permissible1 and the engineer may choose the one which in his opinion seems best adapted to the character of the work to be done1 and the conditions under which it must be prosecuted4 ,in the third class of specifications1 met with more frequently than they should be1 the engineer undertakes to prescribe not only the character of the materials to be used and the methods to be pursued1 but also the results to be attained4 ,the position thus assumed is illogical1 and often unreasonable1 and may lead to complications between the engineer and the contractor4 ,if a contractor be required to turn out a product which shall conform to certain standards1 he may properly be given much1 if not full latitude1 as to how the stipulated results shall be secured1 and may be held fully responsible for the outcome2 if on the other hand the engineer chooses to specify with more or less minuteness the character of the materials to be used and the methods of construction to be followed1 and enforces compliance therewith1 it seems fair and just that he should assume responsibility for the results produced1 and therefore unfair to hold the contractor to responsibility for consequences arising from the use of materials and methods which he was allowed no choice or latitude in selecting4 ,in street paving work1 of well-known and standard character1 the second class of specifications seems preferable for a number of reasons1 the leading one being that the time required to develop the good or bad quality of the work must usually extend over a considerable number of years1 and the conditions to which the pavement may be subjected in the meantime are likely to vary so widely that it may be very difficult1 if not impossible1 to prescribe a satisfactory standard of service and endurance4 ,disputes are therefore liable to arise between the municipality and the contractor as to the latter's liability1 or conditions may make it difficult or impossible to hold the contractor to strict account for that liability4 ,it is believed that in the present state of the art it is entirely practicable to so frame specifications for the materials to be used and the methods to be followed in the construction of standard street pavements1 and to so enforce compliance therewith1 that the engineer and the municipality may safely assume responsibility for the quality of the work produced4 ,while it may be true that local conditions sometimes make it very difficult to enforce compliance with specifications1 the same conditions are likely to make it at least equally difficult to secure effective responsibility on the part of the contractor for any long-period guarantee of the work done by him2 and the contractor who negligently or purposely violates the specifications during construction is not likely to be more faithful or scrupulous in living up to any guarantees he may make with regard to the future1 even where the terms and conditions of such guarantees may be clearly defined and indisputable4 ,the writer has discussed the subject of time guarantees as applied to street pavements pretty fully in his book1 8,municipal ,public ,works10 and the above brief statement seems all that is necessary here4 ,in conformity with this view of the matter1 the following specifications aim to set out as definitely and clearly as practicable the requirements for the construction of good pavements of the several standard kinds1 and it is assumed that the engineer will be able to1 and will enforce them4 ,it is1 however1 not infrequently the case that the engineer will be called upon to prepare specifications for new1 or patented1 or proprietary pavements advocated by their promoters1 the value or usefulness of which have not been sufficiently established by experience1 and for which the data for detailed1 definite specifications are not yet available4 ,in such cases the wisest course to follow is to confine the precise specifications to the general or standard parts of the work1 while stipulating only the results to be attained with regard to those features of the work that are proprietary or questionable1 thus placing upon the promoter or his contractors full responsibility for such results as are promised or guaranteed4 ,this applies to new or comparatively untried materials or processes1 whether patented or not4 ,a proposed form of general specifications to cover such cases is offered herein4 ,it is usually unwise to adopt or to incorporate in the municipal specifications those prepared or offered by the promoter or patentee1 which are often brief1 incomplete1 and indefinite1 and are sometimes carefully1 and even cunningly1 drawn to evade final responsibility4 ,no attempt has been made to submit specifications for proprietary or patented pavements1 or those composed wholly or in part of materials which are patented or protected by trade-marks4 ,the owners or contractors engaged in constructing these pavements1 often1 if not usually1 claim the right to dictate the material parts of the specifications under which such work shall be done1 and the municipal engineer who is called upon to construct such pavements1 must1 in each case1 determine whether the specifications offered are adequate and satisfactory1 and the extent to which he feels justified in accepting responsibility for the results4 ,naturally1 the contractor or promoter1 even if competent to prepare specifications1 cannot be expected to bind himself within closer limits than he thinks necessary to secure the work4 ,in many such cases the form of general specifications for 8untried or experimental pavements0 given herein might appropriately be used4 ,the engineer is1 in common with all men1 fallible1 and he can hardly hope1 in the preparation of specifications1 to make them perfect2 to cover every item and particular2 or to escape some ambiguities of expression1 and some degree of indefiniteness4 ,the writer can only claim that he has aimed1 in the light of a considerable experience1 to set out as fully and definitely as practicable the requirements for the proper construction of high-class street pavements1 and has endeavored to avoid loose or obscure terms and expressions4 ,the ideal specification is one that furnishes a wholly sufficient guide to the accomplishment of the desired purpose2 that provides for every possible contingency which may arise1 and is couched in language which not only means exactly what it was intended to mean1 but is incapable of any other interpretation4 ,it is needless to say that no example of such a perfect specification can be instanced as a model4 ,it has been the aim to make these specifications fair and just to the contractor2 that is1 to require of him no impracticable or indefinite service1 or the assumption by him of risks other than those fairly involved in the business conduct of the work4 ,if the plans and specifications for any work which a contractor bids upon are so full1 specific1 and clear1 that he may know exactly what he will be expected to do1 and if they do not require him to assume unusual chances and risks1 he may intelligently name prices which he believes will compensate him for the service4 ,having done so1 his proposal having been accepted1 and a contract entered into accordingly1 the engineer and the municipality have a right both in law and equity to demand that he will do exactly and fully what he has contracted to do4 ,no excuses on his part can be valid and none should be accepted4 ,he may in all fairness and justness be required to 8toe the mark0 strictly4 ,to the neglect to recognize and enforce these principles is chargeable the greater part of the poor and unsatisfactory work so common in street pavement work in our cities4 ,unexpected contingencies may1 of course1 arise where some changes and concessions may be proper and just1 but these should be1 and usually are1 very rare4 ,on the other hand1 sweeping general clauses in contracts and specifications intended to catch the contractor 8goin' or comin'10 unnecessarily stringent stipulations which were never intended to be strictly enforced1 but were put into the specifications with the idea that they would help hold the contractor up to a high standard1 and 8one-sided0 contracts intended to give the municipality an unfair advantage over the contractor1 are as inadvisable in policy as they are wrong in principle4 ,nothing should be put in a specification that is not clearly essential to secure the results aimed at1 and1 this having been done1 every requirement should be enforced4 ,the existence in specifications of requirements that are not intended to be enforced1 gives the contractor a pretext for neglecting others that may be important4 ,in these specifications will be found a number of details that are often not regarded as important and which1 when found in paving specifications1 the contractor is frequently allowed to ignore4 ,in the writer's opinion1 based upon his experience in street paving1 every one of these requirements is essential to the production of high-class work1 which1 it is hardly necessary to argue1 is1 in the end1 the most economical work from the standpoint of the municipality4 ,it may be argued that the adoption and enforcement of these specifications would have the effect of raising prices4 ,in many cases this would doubtless prove true4 ,contractors are entitled to a fair and reasonable compensation for their services4 ,it is admitted that in some cities the prevailing prices for some kinds of pavements are below the actual cost of the work if it were done in a proper manner1 conforming strictly to the specifications4 ,illogical as it undoubtedly is1 the low price at which work is taken is sometimes considered a sufficient reason for accepting work below standard4 ,the consequence is that bidders not only count upon concessions and lax enforcement of the specifications1 but bid lower and lower1 expecting that further concessions will enable them to get out with an undeserved profit4 ,this is one of the most serious evils in the paving business to-day1 and the highest public interests demand a thorough reform4 ,low first cost1 desirable as it may be1 is the poorest economy if it be secured at the sacrifice of the quality of the work4 ,if one pavement costs twenty per cent4 more than another1 but renders forty per cent4 more service1 it is obviously the cheaper of the two4 ,contractors are prone to contend that this or that provision in a specification is unusual1 unnecessary or unfair4 ,in dealing with them the engineer should bear in mind that no requirement of a specification that is clearly and definitely stated1 so that the bidder may understand exactly what it means and what he will be expected to do1 and may frame his prices accordingly1 can be unreasonable or unfair to the contractor4 ,unusual or unnecessary requirements may result in unwarrantably increasing the cost of the work1 and this may raise a question between the engineer and the municipality employing him1 but it can furnish no occasion for questions of fairness or unfairness between the contractor and the engineer4 ,the relations that should exist between the contractee and the contractor1 and the attitude of the engineer toward the contractor have been widely discussed and are quite well understood from both the ethical and legal standpoint4 ,it is well to bear in mind that when a contract is duly entered into1 both the parties thereto are equal before the law4 ,neither can impose upon the other terms or conditions that are not clearly included in or to be fairly inferred from the contract itself4 ,the assumption that either party has superior or extra rights not expressed or to be fairly inferred from the written agreement1 or in accordance with the established rulings of the courts1 is wholly without warrant4 ,the smallest contractor is1 in this respect1 upon an equal footing with the largest city government for which he may undertake to do contract work4 ,it is not infrequently the case that the city assumes a superior and dictatorial attitude not in harmony with these principles1 and it is too common for the contractor to seek to evade or to escape from clear contractural obligations4 ,in neither case is the action warranted by fairness1 justice1 or law4 ,it should be needless to say that the attitude of the engineer toward the contractor should be one of unyielding and uncompromising requirement that the contract and specifications shall be fully and faithfully complied with1 but at the same time one of absolute fairness and even helpfulness to the contractor4 ,the ideal relation1 which should be more commonly attainable than it appears to be1 is that of helpful cooperation to bring about the results the contract and specifications were intended to secure4 ,in line with the principles here outlined some observations upon the preparation of contracts and specifications are appropriate4 ,it is the general practice to include in and make a part of 8,the ,contract0 7herein for convenience called ,the ,general ,contract7 all the various documents that are supposed to relate directly to the transaction as a whole4 ,the separate parts of such a general contract may vary in number or character1 but the principal ones are the following3 #a4 ,the advertisement for proposals4 #b4 ,instructions to bidders4 #c4 ,the proposal submitted4 #d4 ,the contract proper4 #e4 ,the specifications4 ,each of these should be drawn to cover fully and clearly its appropriate purpose or function but nothing more4 ,it is not unusual to find1 even in the instructions to bidders1 stipulations that properly belong in the contract or specifications1 and it is quite common to find in the contract proper a lot of matter that properly belongs in the specifications only4 ,in such cases there is liable to be more or less confusion as to the actual meaning or requirements of the general contract as a whole1 which may lead to serious misunderstandings and complications between the parties thereto4 ,the several documents composing the general contract are likely to be prepared by different persons1 looking at the transaction from different points of view1 and often not wholly familiar with the scope1 intent and language of the other documents4 ,there is therefore a possibility1 at least1 of indefinite1 if not of conflicting expressions which are open to different interpretations1 particularly in the light of special or unexpected conditions that may arise during the progress of the work or the settlement therefor4 ,it would tend to eliminate or avoid the possibility of such complications if each of the several documents confined itself strictly to its appropriate function in the general contract4 ,advertisements for proposals may be divided into two general classes4 ,the one is brief in form and substance1 simply stating that proposals for a certain named work will be received at a stated place and time1 and referring those interested to documents on file at a stated place for all further information4 ,this is the general form adopted by the ,united ,states ,war ,department for the many projects carried out by contract under its direction4 ,a sample advertisement taken from a current technical journal is as follows2 ,,treasury ,,department1 ,,office ,,of the ,supervising ,architect1 ,washington1 ,d4 ,c41 ,october #aj1 #aiab4 ,sealed ,proposals will be received at this office until #c o'clock p4 m4 on the #ast day of ,november1 #aiab1 and then opened1 for an electric passenger elevator in the ,united ,states post office1 ,bellingham1 ,wash41 in accordance with the drawing and specification1 copies of which may be had at this office at the discretion of the ,supervising ,architect4 ,,oscar ,,wenderoth1 ,supervising ,architect4 ,the other general class of advertisement1 very commonly used by municipal corporations1 is much longer and more elaborate1 giving a condensed statement of the character of the work to be done1 the conditions under which proposals are invited and will be received1 and a schedule of the quantities of work involved1 together with other particulars4 ,a typical example of such an advertisement1 taken from the same periodical1 is here given3 ,,pumping ,,machinery--,,roseland ,,pumping ,,station ,,department ,,of ,,public ,,works ,,chicago1 ,,ill41 ,october #b1 #aiab4 ,sealed proposals will be received by the ,city of ,chicago until #aa ,a4 ,m4 ,wednesday1 ,october #cj1 #aiab1 at ,room #djf1 ,city ,hall1 for furnishing and erecting at ,roseland ,pumping ,station one vertical triple expansion crank and fly wheel pumping engine of a capacity of twenty-five million 7#be1jjj1jjj7 gallons per day against a normal head of one hundred and forty feet 7#adj74 ,this proposal also includes the dismantling of a similar engine now at ,lake ,view ,pumping ,station1 transporting and erecting it at ,roseland ,pumping ,station1 together with the furnishing and erection of certain auxiliaries and appurtenances1 according to plans and specifications on file in the office of the ,department of ,public ,works of said city1 ,room #djf1 ,city ,hall4 ,proposals must be made out upon blanks furnished at said office1 and be addressed to said ,department1 indorsed 8,proposals for ,pumping ,machinery1 ,roseland ,pumping ,station10 and be accompanied with ,five ,thousand 7#e1jjj7 ,dollars in money or a certified check for the same amount on some responsible bank located and doing business in the ,city of ,chicago and made payable to the order of the ,commissioner of ,public ,works4 ,the ,commissioner of ,public ,works reserves the right to reject any or all bids4 ,a deposit of ,one ,hundred ,dollars 7#ajj7 will be required to insure safe return of the plans4 ,no proposal will be considered unless the party offering it shall furnish evidence satisfactory to the ,commissioner of ,public ,works of his ability1 and that he has the necessary facilities together with sufficient pecuniary resources to fulfill the conditions of the ,contract and ,specifications1 provided such ,contract should be awarded to him4 ,companies or firms bidding will give the individual names as well as the name of the firm with their address4 ,l4 ,e4 ,mc,g,a,n,n1 ,commissioner of ,public ,works4 ,such advertisements as this may be required by statutes or ordinances1 and in that case are1 of course1 proper and necessary4 ,even where not so required they may be considered advantageous1 because they give prospective bidders more complete information as to the character and magnitude of the work1 and may enable them to decide at once whether they care to pursue the matter further4 ,but on the whole1 the shorter form of advertisement1 if permissible1 seems preferable1 because it refers the enquirer directly to the original and official sources of information1 the forms to be used1 the contract1 specifications and estimated quantities of work1 exactly as they will and must be presented to all bidders1 and as they will appear in the subsequent stages of the transaction1 and leaves1 therefore1 no room for possible confusion of statements between the advertisement and the other documents4 ,furthermore1 the cost of the shorter form of advertisement is much less1 and this is often a matter of some importance4 ,instructions to bidders should be confined strictly to such information and directions as the bidder may need to properly and intelligently make up and submit his proposal in accordance with the requirements relating thereto4 ,this should include primarily1 a reference to the contract and specifications for all general and detailed information about the work to be done1 but should carefully avoid any statements or language that might be construed to add to1 take from1 limit or modify the contract or specifications4 ,perhaps the briefest and best statement of what this document should or should not contain is that it should be so framed that1 except as a matter of record1 its office and usefulness should absolutely end with the award and signing of the contract4 ,no one who is not a lawyer can presume to say just what the contract proper should contain or cover1 particularly as this may vary with the requirements of statutes and ordinances in force in a given city4 ,it would seem logical and proper1 however1 to separate the special functions of contracts and specifications in such a way that each should cover a distinct field of its own1 and be free from encroachment upon the proper domain of the other4 ,with such a conception of the proper domain of each1 one might safely say that the contract should undertake to set out only the legal and contractural relations of the parties thereto1 and should refer to the plans and specifications for all detailed instructions as to the actual performance of the work and the results to be secured4 ,in the preparation of specifications for any public work the main points to be kept in mind are fulness1 definiteness1 and exact expression4 ,while brevity and conciseness are desirable qualities in any document1 they should not be secured at the expense of completeness and precision of statement4 ,even the frequent repetition of words1 phrases and sentences throughout a document1 where it is necessary to avoid the possibility of misunderstanding or ambiguity1 should be resorted to freely4 ,exact description and definition are more important than literary style1 though they may often be successfully combined4 ,of course1 it is not possible or necessary to go into minute detail with regard to every part of the work4 ,certain things may be safely assumed to be required by established practice or trade usage4 ,if1 for instance1 it is specified that certain lumber shall be 8dressed0 this word has a well-understood meaning in the trade and it is unnecessary to stipulate how the dressing shall be done or its character or quality1 though it may be necessary to say whether it is to be dressed on one or more sides4 ,the proper preparation of specifications for any work involves a clear1 distinct and complete conception1 determination and design of what is to be done2 of the conditions that are likely to be met with in carrying it out2 and of alternate plans that these conditions may necessitate4 ,this may not always be possible1 for the engineer is not omniscient4 ,but careful study and maturity of design will enable him to avoid the great majority of such indefinite expressions as 8or in such other manner as the engineer may direct10 8in accordance with the instructions of the engineer10 etc4 ,a great many of the items to which such expressions are intended to and do apply in practice1 could be definitely settled before the specifications are prepared and thus all uncertainty on the part of both engineer and contractor be avoided4 ,to illustrate3 specifications for block pavement commonly stipulate that the blocks shall be set in rows running at right angles to the axis of the street1 except at street intersections1 where the engineer may direct them to be laid at a different angle4 ,there is usually no good reason why the engineer should not determine beforehand at which1 if any1 street intersections the general rule should be changed and so state in the specifications4 ,these may be and usually are unimportant matters which may not much affect one way or the other the cost to the contractor4 ,but they often prove otherwise1 and the contractor is entitled to know when he submits his proposal just what he will be required to do4 ,of course it may develop during the progress of the work that changes from the original plan will become necessary1 but these should be provided for in some such definite and previously stipulated manner as outlined in ,sect4 #c of the following specifications4 ,the practice of inserting1 either in the specifications or the contract1 a clause making the engineer judge and arbiter in any differences that may arise between the city and the contractor1 and providing that his decision in all such cases shall be final1 is as unwise as it is often illegal4 ,such clauses are based on the assumption that the engineer is a competent as well as a disinterested party in the transaction1 an assumption that is usually wholly wrong1 though to their honor it may be said that the confidence thus reposed in engineers is seldom abused4 ,but the fact is that the engineer is never actually a disinterested party4 ,he is employed and paid by the city to look after its interests1 and is under no obligations to the contractor other than those named in the contract and specifications and his sense of justice1 propriety and professional honor4 ,he would be recreant to his duty if in all nicely balanced matters of doubt he did not espouse the side of his employer4 ,moreover1 his personal interests are often involved4 ,having prepared the plans1 specifications and estimates for the work1 he is naturally and properly anxious that it shall be successful and that the cost shall not exceed that estimated4 ,under all these conditions it is hardly possible for any human being to be a wholly disinterested and unprejudiced judge4 ,no broad-minded and conscientious engineer desires to be placed in such a difficult position1 and it is as unfair as it is unwise and improper to require him to assume it4 ,there are1 however1 a number of matters of fact in reference to which it is proper and necessary to make the judgment and decision of the engineer controlling and final1 unless it may be shown that his decision is clearly erroneous or affected by improper motives1 or by fraud4 ,some one must necessarily be made the immediate and final judge as to whether the quality of materials and workmanship is in accordance with the requirements of the plans and specifications1 and as to the quantity of work actually performed1 and these duties and responsibilities are very properly placed upon the engineer4 ,it not infrequently occurs that specifications are not drawn as clearly as they should be in the matters of methods of measuring the work and of applying contract unit prices1 and indefiniteness and carelessness in this regard are often a source of misunderstanding and dispute between the engineer and the contractor4 ,it is a good practice1 followed by many able engineers1 after specifying how a certain part of the work shall be done1 to state how it shall be measured and paid for at the contract unit prices4 ,in many respects it is desirable that all the work to be done under contract should be quite fully itemized1 and a unit price named for each kind of work4 ,it is the custom in many cities to name only certain leading items of the work to be done under a paving contract1 as for the pavement complete1 furnishing and setting new curbing1 redressing and resetting old curbing1 and possibly a few other leading items1 and to require that all necessary incidental work shall be done by the contractor without cost to the city2 or1 in other words1 he must take this possible extra work into consideration in naming his unit prices for the leading items of the work4 ,as the quantity of this incidental work is often not stated1 and the contractor has no means of ascertaining it1 he must guess1 as intelligently as he may be able1 how much he should add to his unit prices to cover its cost4 ,if he is a prudent contractor he will be sure to add enough to prevent any possible loss on this account4 ,in most cases the quantities of this incidental work can be determined and scheduled by the engineer with the more important items1 and the contractor may be required to name unit prices for it4 ,true1 there are likely to develop during the progress of the work some items that could not be foreseen or that were overlooked4 ,in some cities such contingencies are provided for by a clause in the contract or specifications scheduling1 by name1 all the incidental minor items of work that experience has shown are likely to be met with in street paving contracts1 and naming fair unit prices which the contractor will be paid for each1 should it occur4 ,the contractor may then feel assured that however much the quantity of such incidental work may vary1 he will receive compensation proportionate thereto1 and he may name his prices for the main items with more confidence4 ,under such conditions it is reasonable to expect closer figures than he would be willing to name if an unknown quantity of incidental work for which no separate pay is provided had to be taken into consideration4 ,sub-division of unit prices is also desirable in order that the engineer may be able to analyze and record the elements that make up the aggregate cost of the work4 ,thus1 in the case of the construction of a new sheet asphalt pavement it is common to ask for a single price for the pavement complete1 including a five year guarantee4 ,now the work will consist of several distinct operations or kinds of work for each of which a separate price might be named3 #a4 ,the grading of the street and preparation of the sub-grade4 ,the quantity of this work will vary on different streets and is best reckoned by the cubic yard of material excavated4 #b4 ,a price1 either per cubic yard or per square yard for the concrete foundation4 #c4 ,a price per square yard for the asphalt pavement proper4 ,this might1 if desired1 be sub-divided into separate prices for the base-course and the surface-course4 #d4 ,a price per square yard for guaranteeing the pavement for five years4 ,such sub-division would1 it is true1 increase the work of final computation but if of no other value1 the detailed costs would be a great aid to the engineer in estimating the reasonable cost of future work where the relative quantity of these detailed parts varied4 ,,specifications ,for ,grading and ,paving1 or ,repaving with44 44444444 44444444 44444444444444 4444 ,pavement on a444 444444444 4444444444 444444 ,foundation1 the ,roadway of44444 44444444 44444444444 444444444444 4 444444444444 ,street1 from444444 4444444444 4444444444444 4444444444444 to4 4444444 4444444 44444444444 444444444444 44444444 together with work incidental thereto4 ,,general ,,description ,,of ,,work ,the work embraced in and to be done under this contract consists of grading the entire street from curb to curb between the limits named1 including the removal or readjustment of the pavement now on the roadway1 setting and resetting curbing1 laying or relaying sidewalks where required1 furnishing all new material and performing all the labor required for paving the roadway1 together with all incidental work necessary to complete the whole in a proper manner1 in accordance with the contract1 the plans on file in the office of the ,city ,engineer1 these ,specifications and the instructions of the ,city ,engineer1 herein referred to as the ,engineer1 or his authorized agents4 ,,references ,the numbered divisions of these specifications are herein designated as 8sections10 each being referred to by the number standing at its beginning4 ,where reference is herein made to any such section number it shall be considered equivalent to a quotation of that section4 ,the plans and drawings relating to this work1 on file in the office of the ,city ,engineer are designated as 444 #a4 ,authority4--,wherever1 in these specifications1 the words1 the ,city1 are used1 they shall be understood to refer to the duly constituted municipal government of the city of 444 or its authorized agents1 acting within the authority specifically conferred upon them by the said municipal government4#a ,wherever1 in these specifications1 the words1 the ,engineer1 shall be used1 they shall be understood to refer to the ,city ,engineer of said city1 or his deputies or assistants1 acting within the authority conferred upon them by the ,city ,engineer4 ,but no agent of the city shall have power to revoke1 alter1 enlarge or relax the stipulations or requirements of these specifications1 except in so far as such authority may be specifically conferred in or by the specifications themselves1 without the formal authorization so to do1 conferred by the contract of which these specifications are a part1 or by ordinance1 resolution or other usual official action of the city4#b #b4 ,interpretation4--,in case of any actual or alleged disagreement or discrepancy between the contract1 these specifications1 and the plans for the work on file in the office of the ,engineer1 the language and provisions of the contract shall take precedence and prevail2 and the ,engineer shall determine in each case whether the specifications or the plans shall be followed4 #c4 ,the ,engineer shall have the right to make such changes in the plans and specifications of the work as he may deem necessary or desirable or to provide for unexpected conditions or contingencies that may develop at any time after the signing of the contract1 or during the progress1 or before the final acceptance of the work2 provided that all such changes do not involve an aggregate increase or decrease in the cost of the work1 as shown by his estimates1 of more than ten 7#aj7 per cent4 ,the contractor shall accept such changes when made1 as a part of the original contract and specifications1 subject to all the provisions and conditions thereof4 ,but before any such changes shall become valid and before the contractor shall begin the particular work involved in such changes1 the increased or decreased cost of the work by reason of such changes1 above or below what it would have been under the original plans and specifications1 shall be agreed upon in writing between the engineer and the contractor4 ,and when the whole work1 including such changes1 shall have been completed and accepted by the engineer1 the sum or sums so agreed upon shall be added to or deducted from the sum that would have been due the contractor if no such changes had been made4 #d4 ,quality of ,material and ,work4--,the judgment and decision of the ,engineer as to whether the materials supplied and the work done under this contract comply with the requirements of these specifications1 shall be conclusive and final4 ,no material shall be used in the work until it has been examined and approved by the ,engineer1 or his authorized agents4 ,all rejected material must be promptly removed from the work and replaced with that which is acceptable to the ,engineer1 and all improper or defective work must be corrected1 and1 if necessary1 removed and reconstructed so as to comply with these specifications and the instructions of the ,engineer4 ,in all matters of detail not specifically covered by the specifications the work shall be well and skillfully done in accordance with the best trade or art customs and standards for work of like character and purpose4 #e4 ,inspection4--,the ,engineer may provide for the inspection1 by assistants and inspectors under his direction1 of all materials used and all work done under this contract4 ,such inspection may extend to all or any part of the work1 and to the preparation or manufacture of materials to be used1 whether within the limits of the work on the street1 or at any other place4 ,the ,engineer and his inspectors shall have free access to all parts of the work1 including mines1 quarries1 manufactories1 or other places where any part of the materials to be used is procured1 manufactured or prepared4 ,the ,contractor shall furnish the ,engineer all information relating to the work and the material therefor which the ,engineer may deem necessary or pertinent1 and with such samples of materials as may be required4 ,the ,contractor shall1 at his expense1 supply inspectors with such labor and assistance as may be necessary in the handling of materials for proper inspection4 ,inspectors shall have authority to reject defective material and to suspend any work that is being improperly done1 subject to the final decision of the ,engineer4 ,inspectors shall have no authority to permit deviations from1 or to relax any of the provisions of these specifications without the written permission or instruction of the ,engineer2 nor to delay the ,contractor by failure to inspect materials and work with reasonable promptness4 ,the payment of any compensation1 whatever may be its character or form1 or the giving of any gratuity1 or the granting of any valuable favor1 by the ,contractor to any inspector1 directly or indirectly1 is strictly prohibited1 and any such act on the part of the ,contractor will constitute a violation of these specifications4#c #f4 ,injuries to ,persons and ,property4--,the ,contractor shall be held alone responsible for all injuries to persons1 and for all damages to the property of the city or others1 caused by or resulting from the negligence of himself1 his employees or agents1 during the progress of1 or connected with the prosecution of the work1 whether within the limits of the work1 or elsewhere4 ,he must restore all injured property1 including sidewalks1 curbing1 sodding1 pipes1 conduits1 sewers and other public or private property to a condition as good as it was when he entered upon the work4 #g4 ,sanitary ,conveniences2 ,nuisances4--,the ,contractor shall provide all necessary privy accommodations for the use of his employees on the street1 and shall maintain the same in a clean and sanitary condition4 ,he shall not create nor permit any nuisance to the public or to residents in the vicinity of the work4 #h4 ,public ,convenience4--,no material1 or other obstruction shall be placed within five feet of fire hydrants1 which must be at all times readily accessible to the ,fire ,department4 ,during the progress of the work the convenience of the public and of the residents along the street must be provided for as far as practicable4 ,convenient access to driveways1 houses and buildings along the street must be maintained wherever possible4 ,temporary approaches to and crossings of intersecting streets and sidewalks must be provided and kept in good condition1 wherever practicable4 #i4 ,barriers1 ,lights1 ,watchmen4--,the ,contractor shall provide and maintain such fences1 barriers1 8street closed0 signs1 red lights1 and watchmen as may be necessary to prevent avoidable accidents to residents and to the public4 #aj4 ,disorderly ,employees4--,disorderly1 intemperate1 or incompetent persons must not be employed1 retained1 or allowed upon the work4 ,foremen or workmen who neglect or refuse to comply with the instructions of the ,engineer1 shall1 at his request1 be promptly discharged1 and shall not thereafter be re-employed without his consent4 #aa4 ,order and ,progress of ,doing ,work4--,the work under this contract shall be prosecuted at as many different points1 at such times1 and in such sections along the line of the work1 and with such forces as the ,engineer may from time to time deem necessary1 and direct1 to secure its completion within the contract time4 ,not more than one thousand 7#a1jjj7 linear feet of the street shall be torn up1 obstructed or closed to travel at any one time without the written permission of the ,engineer4 ,completed portions of the pavement shall be opened to travel as directed by the ,engineer1 but such opening shall not be construed as an acceptance by the ,city of the work done4 ,where thus opened to public travel by the direction of the ,engineer1 the ,contractor will not be held responsible for injuries to the work caused by such travel or public use1 pending the final completion and acceptance of the whole work4 #ab4 ,grade and ,contour of ,pavement4--,roadway pavements shall be laid to such grades1 crown and contour of surface as the plans may show or the ,engineer may direct1 and the surface of the completed pavement shall conform accurately to such grades1 crown and contour4 ,the designed surface of the completed pavement shall be considered as the datum or plane of reference in fixing the location or level of the sub-grade1 of the pavement foundation1 and of structures connected therewith4 ,it will be hereafter referred to in these specifications as 8,the pavement datum40 #ac4 ,city ,monuments or ,stakes4--,the ,contractor must carefully protect from disturbance or injury all city monuments1 stakes and benchmarks1 and shall not excavate nearer than five feet to any of them without the permission of the ,engineer2 or until they have been removed1 witnessed1 or otherwise disposed of by the ,engineer4 #ad4 ,old ,material4--,all material or structures removed from the street and not required for the new construction1 but which the city may desire to reserve1 shall be delivered and neatly piled up in a corporation yard or elsewhere1 by the ,contractor1 as the ,engineer may direct4 ,such reserved material shall be considered in the custody of the ,contractor until delivered at the place designated1 and he will be held responsible for its care and protection1 and must make good any losses occasioned by damage1 theft1 or misappropriation while it is on the street or en route to the place of storage4 ,if the ,contractor shall be required to haul such reserved material more than one-half mile1 he shall be paid a reasonable price1 to be agreed upon in advance1 for the haul exceeding that distance4 ,material taken from the work which is to be used in the new construction shall be compactly piled where it will least obstruct the sidewalks or adjoining sections of the street1 and properly protected by the ,contractor until it is required for use4 ,all old material removed from the work1 including the material excavated in preparing the sub-grade1 not reserved by the ,city nor to be used again in the work1 shall belong to the ,contractor and must be removed by him from the street as promptly as possible4 ,it must not be placed on the sidewalks or adjacent streets1 nor on any other street or property belonging to the ,city1 nor on the property of private owners1 without the written consent of the ,engineer1 or the owner of the property4 #ae4 ,storage of ,new ,material4--,the material for construction when brought upon the street shall be neatly piled so as to cause as little obstruction to travel as possible1 and so that it may be conveniently inspected4 #af4 ,rebuilding and ,adjusting ,street ,structures4--,catch basins1 manhole1 sewer and water frames and covers1 sewer inlets1 water pipes and other conduits1 belonging to the ,city and within the limits of the work1 shall1 if necessary1 be reset to the new lines and grades of the street and for this purpose good brick masonry of the original thickness1 laid in ,portland cement mortar shall be used4 ,great care must be taken to set all such structures as project through the pavement exactly to the grade and contour of the new street surface1 and any defects in the conformity of such structures to the pavement datum1 discovered at the time1 or during the progress of the work1 or during the guaranty period1 stipulated in ,sec4 #be shall be promptly remedied by the ,contractor4 #ag4 ,clean ,sidewalks4--,during the progress of the work1 the sidewalks and portions of the street adjoining the work1 or in its vicinity1 must not be obstructed or littered more than may be absolutely necessary1 and the adjacent sidewalks must be kept clean4 #ah4 ,connection ,with ,existing ,pavements or ,streets4--,wherever a new pavement joins or abuts against an existing pavement of a different kind1 or an unpaved street1 either at the end of the new pavement or at cross or intersecting streets1 a line of stone headers shall be provided and set4 ,the stone shall be of sound1 hard limestone1 sandstone1 granite or bluestone1 free from injurious imperfections4 ,the separate stones shall be not less than three 7#c7 feet long1 at least eighteen 7#ah7 inches deep1 not less than four and one-half 7#d7 inches wide at the top1 nor less than three 7#c7 inches wide at the bottom4 ,the top shall be of uniform width for each line of headers1 and shall be dressed square and even4 ,the ends shall be dressed to secure a joint not wider than one-half 77 inch for a depth of six inches from the top1 and the sides dressed so as to secure good contact and close jointing with the pavement4 ,the stones shall be set accurately with their tops at the pavement datum1 on a bed of concrete nine 7#i7 inches wide and six 7#f7 inches deep1 and after being set the trench shall be filled and rammed full of gravel or crushed stone4 ,all existing pavements adjoining or abutting against the new pavement1 with their crosswalks1 curbs1 and gutters1 shall be adjusted1 or taken up and relaid1 to conform to and connect with the pavement datum1 to such an extent as the ,engineer may direct4 ,where the new and adjoining pavement are of the same kind1 and headers are not used1 the new and the old pavement must be properly joined and connected1 as the ,engineer may direct4 ,stone headers will be paid for by the linear foot at the contract price for that item1 and the other work embraced in this section will be paid for at the contract prices for the several items1 where such contract prices are provided2 otherwise the work shall be considered as incidental work and shall be done at the expense of the ,contractor4 #ai4 ,curbing to be ,completed in ,advance4--,the setting of all new curbing and guttering and the redressing1 resetting or readjustment of all old curbing must be completed at least #ajj feet in advance of the construction of the street foundation4 #bj4 ,final ,cleaning ,up4--,immediately after the completion of the work or any consecutive portion of it1 the ,contractor shall remove from it all unused material1 refuse and dirt placed by him on1 or in the vicinity of the work1 or resulting from its prosecution1 and restore the street to a condition as clean as before the work was begun2 and the new pavement shall be properly cleaned4 #ba4 ,measurements and ,computations4--,unless otherwise distinctly provided in the contract and specifications1 measurements1 computations and payments will be based upon the actual quantities of completed work1 customary or conventional methods of measurement and computation to the contrary notwithstanding4 ,the area of street pavement shall be reckoned in square yards of completed pavement surface1 deducting manholes1 inlets and other openings in the surface of the pavement having an area of over three 7#c7 square feet4 ,unless separately paid for under the contract1 stone headers and crosswalks will be measured as a part of the pavement surface4 #bb4 ,the price for the pavement per square yard shall1 unless otherwise stated herein1 include the preparation of the sub-foundation1 the construction of the foundation1 the cushion course1 and the pavement complete1 including all the materials and labor required therefor4 #bc4 ,incidental ,work at ,contractor's ,expense4--,all the work to be done by the ,contractor for which specific unit prices are not named in the contract1 specified and enumerated in ,sections #d1 #e1 #f1 #g1 #h1 #i1 #ab1 #ac1 #ad1 #ae1 #af1 #ag1 #ah1 #ai1 and #bj1 as well as any minor details of work not specifically mentioned in the specifications1 but obviously necessary for the proper completion of the work1 shall be considered as incidental1 and as being a part of and included with the work for which prices are named in the contract4 ,the ,contractor will not be entitled to any extra or additional compensation therefor4 #bd4 ,extra ,work4--,the ,city may require the ,contractor to furnish such additional materials and to do such additional work1 not provided for in the contract and these specifications1 but which may be found necessary or pertinent to the proper prosecution and completion of the work embraced in the contract1 at prices to be agreed upon in writing1 in advance4 ,but no work other than that included in the contract and these specifications and which is covered by and to be paid for at the prices named in the contract1 shall be done by the ,contractor except upon a written order from the ,engineer1 which order shall describe the work to be done and name the compensation agreed upon therefor4 ,in the absence of such written order from the ,engineer the ,contractor will not be entitled to payment for any such additional or extra work4 ,in the same manner the city may omit or dispense with items or parts of the work1 by previous agreement with the contractor1 and a like written order by the engineer4 ,but such additions1 omissions or alterations shall not together increase or decrease the aggregate cost of the whole work more than fifteen per cent4 7#ae74 ,any changes in the plans1 specifications1 character of material used or method of doing the work that may increase or decrease the aggregate cost of the work more than fifteen per cent4 7#ae7 may be authorized and validated only by a formal1 supplemental contract1 regularly executed by all the parties to the original contract4#d #be4 ,guaranty4#e--,the ,contractor shall guarantee that all the materials used and all the work done under this contract shall fully comply with the requirements of these specifications1 the plans herein before referred to and the instructions of the ,engineer4 ,any defects in the completed work1 or any part of it1 or any failure of the work to fully perform or endure the service for which it was intended1 which1 in the opinion of the ,engineer1 are attributable to the use of materials1 skill1 or workmanship not in compliance with the said specifications1 plans and instructions1 within a period of 444 years after the date of the certificate of completion and acceptance1 shall be regarded as prima facie and conclusive evidence that the ,contractor has failed to comply with the said specifications1 plans and instructions4 ,and the ,contractor shall1 at his own expense1 at such time and in such manner as the ,engineer may direct1 repair or take up and reconstruct any such defective work1 in full compliance with the original specifications1 plans and instructions4 ,and as surety for the performance of this guaranty the ,contractor's bond1 required by the contract1 shall remain in full force until the expiration of the period of 444 years above stipulated in this section4 ,,preparing ,,the ,,sub-,,grade #bf4 ,grading4--,the whole area to be occupied by the pavement and its foundation shall be excavated or filled up to a sub-grade at such an elevation that after being compacted by the roller1 the surface will be 444 inches below the pavement datum1 and truly parallel thereto4 ,in excavating1 the earth must not be disturbed below the sub-grade4 ,plowing will not be permitted where the depth of earth to be removed is less than five 7#e7 inches1 and in no case must the plow be allowed to penetrate to within less than one inch of the sub-grade4 ,places that are found to be loose1 or soft1 or composed of unsuitable material1 below sub-grade1 must be dug out and refilled with sand1 or other material as good as the average of that found on the street4 ,where the natural surface of the ground shall be below the sub-grade1 or shall become so by the removal of old pavement or other structures1 it must be filled to the sub-grade in layers not exceeding five inches in depth1 and each layer shall be thoroughly rolled or rammed before the next layer is placed upon it1 and when the filling is completed the filled area must be properly trimmed and compacted by rolling or ramming to the true sub-grade1 as in excavation4 ,the material excavated from the street may be used for such filling1 provided it be of suitable quality4 ,where it cannot be thus procured from the street it must be obtained by the ,contractor elsewhere1 in which case the actual quantity so obtained1 measured after it is compacted in the street1 will be paid for at the contract price for 8earth filling40 ,the price bid for 8earth excavation0 will be paid for all material excavated above the sub-grade1 measured in place on the street1 which price includes the cost of disposing of the excavated material1 whether as waste or filling1 and of trimming and rolling or ramming the sub-grade1 and of making it ready for the pavement foundation4 ,after the excavation is completed and the surface neatly trimmed1 the whole area shall be well compacted by rolling with a roller weighing not less than five tons4 ,areas inaccessible to the roller shall be rammed until they are as well compacted as the rolled surface4 ,when the rolling is completed the surface must be nowhere more than three-fourths inch below1 nor more than three-eighths inch above the true sub-grade4 ,if1 after the rolling is completed and before the pavement foundation is laid1 the surface shall become disturbed in any way1 it must be replaced and properly compacted4 ,where the soil composing the sub-foundation is found to be wet or 8springy10 a system of soft tile drains1 discharging into the street drainage system1 shall be constructed by the ,contractor1 as directed by the ,engineer4 ,the tile shall be laid in trenches about one foot wide and from one to two feet deep4 ,after the tile is in place the trenches shall be filled with crushed stone or gravel1 well compacted by tamping4 ,the tile will be paid for per linear foot at the contract price for the same1 which price shall include the cost of excavating and refilling the trenches with crushed stone4 ,,pavement ,,foundation #bg4 ,pavement foundation shall consist of hydraulic concrete1 or of old pavement stone relaid1 or of broken stone or gravel1 as may be herein specified1 constructed upon the sub-grade4#f ,,hydraulic ,,concrete ,,foundation #bh4 ,concrete4--,concrete shall be composed of ,portland cement1 sand1 broken stone and water4 #bi4 ,portland ,cement4#g--,portland cement shall be defined as the pulverized product resulting from the calcination to incipient fusion of an intimate mixture of properly proportioned argillaceous and calcareous materials1 and to which no addition greater than three per cent4 has been made subsequent to calcination4 ,specific ,gravity4--,the specific gravity of the dry cement at a temperature of two hundred and twelve 7#bab7 degrees ,f4 shall not be less than #c4aj4 ,fineness4--,it shall be pulverized to such fineness that not more than eight 7#h7 per cent4 shall fail to pass a number one hundred 7#ajj7 sieve and not more than twenty-five 7#be7 per cent4 shall fail to pass a number two hundred 7#bjj7 sieve4 ,time of ,setting4--,at the temperature of sixty 7#fj7 degrees ,f4 mortar made of neat cement shall not begin to set in less than thirty 7#cj7 minutes1 nor set hard in less than one hour1 but must set hard within ten 7#aj7 hours4 ,strength4--,when thoroughly mixed dry with clean1 sharp1 moderately coarse sand1 in the ratio by weight of one part cement to three parts of sand1 and then made into stiff mortar1 briquets made from this mortar and exposed for one day to moist air and immersed in water for the balance of the periods named below1 shall develop a tensile strength per square inch not less than the following3 ,in seven days #age pounds4 ,in twenty-eight days #bej pounds4 ,constancy of ,volume4--,when subjected to standard tests for constancy of volume1 the cement shall show no tendency to swell or crack4 ,composition4--,the cement shall not contain more than one and three-fourths 7#a4ge7 per cent4 of anhydrous sulphuric acid1 nor more than four 7#d7 per cent4 of magnesia4 ,tests4--,cement tests shall be conducted in accordance with the methods recommended by the 8,committee on ,uniform ,tests of ,cement0 of the ,american ,society of ,civil ,engineers4 ,conditions4--,all cement shall be supplied in original packages with the brand of the manufacturer marked on each package4 ,it shall be protected during transportation from rain and moisture4 ,it shall be delivered upon the work at least ten 7#aj7 days 7exclusive of ,sundays and holidays7 before it is to be used1 in order to allow of proper inspection1 and the contractor shall furnish all necessary facilities for such inspection4 ,brands of cement without established good reputation1 or not heretofore used in the ,city of 444 may be rejected2 or they will be accepted only after they satisfactorily pass the #bh-;day test4 ,rejected cement must be at once removed from the street4 #cj4 ,sand4--,sand for concrete shall be composed of grains not softer than hard limestone4 ,it shall be moderately coarse and preferably made up of grains of varying size producing a mass with low percentage of voids4 ,it shall not contain1 in all1 more than seven 7#g7 per cent4 by volume of clay1 loam1 mica scales1 silt1 or other objectionable inorganic matter1 nor more than one 7#a7 per cent4 of organic matter4 #ca4 ,broken ,stone4--,broken stone for concrete shall be of hard and sound limestone or other stone equally hard and durable1 broken to a roughly cubical form4 ,it shall be screened through efficient revolving screens1 and only such fragments as have passed through circular screen openings two and one-half 7#b7 inches in diameter1 shall be used4 ,if the crushed dust and fine fragments be not screened out1 the stone must be so handled that the fine material will be evenly distributed through the mass when it reaches the concrete platform or mixer4#h #cb4 ,water4--,water used for concrete shall be fresh1 and reasonably clean4 #cc4 ,care and ,handling of ,concrete ,material4--,cement must not be allowed to become wet or damp4 ,it shall be stored until used1 whether in storehouses or on the street1 so that no part of the packages shall be nearer than four 7#d7 inches to the ground or pavement1 and shall be effectually covered so that rain cannot reach it4 ,sand and stone1 if stored on the street1 shall be on lumber floors4#i ,the stone shall be thoroughly wetted a sufficient time before being placed in the concrete to allow any surplus water to drain away1 but shall remain moist where it reaches the concrete platform or mixer4 #cd4 ,ratio of ,concrete ,materials4--,concrete will be composed of one part ,portland cement1 444 parts of sand and 444 parts of broken stone1 and the proper quantity of water1 all measured by volume4#aj ,the unit of measurement shall be the barrel of cement which shall be considered as containing four 7#d7 cubic feet4 ,the materials shall each be measured in such manner and with such accuracy that the quantities used will not vary more than seven 7#g7 per cent4 from the quantities required in the ratio named above for each batch of concrete4 #ce4 ,mixing ,concrete4--,if mixed by hand1 concrete shall be mixed on platforms of iron or wood of sufficient size to admit of proper manipulation of the concrete4 ,the sand shall be first spread evenly over the platform and the cement evenly distributed over the sand4 ,these two materials shall then be mixed dry until a uniform and homogeneous mixture is secured4 ,sufficient water shall then be added and the mixing resumed and continued until a mortar of uniform consistency and texture is produced and distributed in an even layer over the platform4 ,the stone shall then be distributed over the mortar and mixed therewith until the mortar is evenly distributed through the mass and every fragment of stone is well coated with mortar1 sufficient additional water being added as the mixing progresses to produce a rather wet1 but not sloppy1 concrete4#aa ,machine mixing of concrete will be preferred1 provided the machine used secures equal accuracy in the ratios of materials and equally as good mixing as prescribed above for hand-mixing4 ,machine-mixed concrete must be delivered from the machine upon a wood or metal platform1 or directly into barrows4 #cf4 ,placing the ,concrete4--,concrete shall be placed on the sub-grade in such a manner as to prevent as far as possible the separation of the mortar from the stone4 ,it shall be evenly distributed in a single horizontal layer of such depth that1 after ramming1 it will be not less than 444 inches thick4 ,immediately after being so placed it shall be well rammed until a compact mass is produced with its upper surface parallel to and 444 inches below the pavement datum4 ,depressions that may appear during the ramming may be filled with concrete of the same composition as used for the foundation1 except that smaller-sized stone shall be used2 mortar alone must not be used for this purpose1 nor shall the upper surface of the concrete be plastered with mortar4 ,the surface of the concrete shall not be broomed or troweled4#ab #cg4 ,setting of ,concrete4--,after the concrete is completed it shall remain undisturbed until it be firmly set4 ,the time allowed for setting shall not be less than five days1 and as much longer as1 in the judgment of the ,engineer1 may be necessary1 depending upon the temperature of the weather and the setting qualities of the cement4 ,during this period no hauling or traveling over the concrete must be permitted unless its surface be first protected by a covering of plank4 ,the ,contractor shall1 if necessary1 keep the concrete moist by wetting it1 with hose1 or otherwise1 until twenty-four 7#bd7 hours before it is to be covered with the pavement surface4 #ch4 ,measurement of ,concrete4--,concrete will be measured and computed in cubic yards as found completed on the street1 the thickness being taken as 444 inches4 ,the contract price for concrete foundation covers the cost of providing all the materials required1 making1 placing and ramming the concrete1 and keeping it moist for the necessary period4 ,,foundation ,,of ,,old ,,paving ,,stone #ci4 ,foundations made of old stone paving blocks shall be constructed as follows3 ,upon the sub-grade prepared as specified in ,section #bf1 shall be spread a layer of good sand to an even depth of one and one-half 7#a7 inches4 ,the paving blocks1 whether taken up from the street to be paved1 or brought from other streets or storage yards1 shall be cleaned of all adhering earth1 dirt and street refuse4 ,the blocks shall then be set on the bed of sand1 on edge1 perpendicular to the grade1 with their long dimension at right angles to the line of the street1 in courses composed of stones of the same width1 extending entirely across and at right angles to the axis of the street4 ,stones in adjoining courses shall break joint at least two inches4 ,joints between courses or stones1 or along the curbstones1 shall not exceed one inch in width4 ,the stone shall be fitted closely around manholes or other structures in the street4 ,the stones shall be so set in the bed of sand that after being rammed as hereafter specified1 their tops shall be at the proper grade4 ,after being thus set in place the stone shall be rammed with paving rammers having wooden faces and weighing not less than thirty 7#cj7 pounds1 so as to force each stone to a good bearing in the sand below1 and to bring its top to a uniform grade1 parallel to and 444 inches below the pavement datum4 ,no stone shall project more than one-fourth 77 inch above the proper grade1 and stones whose tops1 after ramming1 are more than one-half 77 inch below such grade1 shall be raised1 additional sand placed under them1 and reset and re-rammed to the proper grade and bearing4 ,after the ramming shall have been completed1 the joints between the stones shall be filled with mortar4 ,the mortar shall be composed of ,portland cement and sand1 complying with the specifications for these materials in ,sections #bi and #cj4 ,one part of cement and three parts of sand1 by volume1 shall be thoroughly mixed dry1 and then made into mortar with sufficient quantity of water to produce a mortar of such consistency that it will just flow freely into the joints between the stones4 ,all the joints between the stones must be completely filled with this mortar before it has begun to set4 ,the mortar filling shall be brought even with1 but not above1 the tops of the stones4 ,after the filling is thus completed1 the foundation must stand undisturbed until the mortar shall have set firmly1 in no case less than five days4 ,the mortar must be kept moist during the period allowed for setting4#ac ,old stone foundation will be measured in square yards1 in place after completion4 ,the contract price includes the cost of handling and cleaning the stone1 supplying and placing the bed of sand1 setting and ramming the stone1 supplying the materials for1 making and placing the mortar in the joints and watering the street while the mortar is setting4 ,where stone is procured from other streets1 or from storage yards1 the ,contractor will be required to load1 haul and unload them1 and will be allowed for this service a price of 444 cents per cubic yard for loading and unloading1 plus 444 cents per cubic yard for each one-half mile1 or fraction thereof1 over which they are hauled by the nearest practicable route1 the measurement to be made after the stone is set in the street1 without deduction for joints4 #dj4 ,broken ,stone ,foundation4--,the sub-grade for broken stone foundation shall be prepared as specified in ,section #bf1 except that the rolling may be omitted at the option of the ,contractor4 ,the broken or crushed stone shall be of hard1 durable stone4 ,the foundation shall have an aggregate thickness of 444 inches and shall be constructed in two courses1 as follows3 ,the broken stone used in the first course shall be of such size that it will all pass through a screen having openings three 7#c7 inches in diameter1 and will all be retained on a screen having openings one 7#a7 inch in diameter4 ,this stone shall be evenly spread over the sub-grade to such a thickness that after being thoroughly consolidated by rolling1 its upper surface shall be three-fourths inch below1 and parallel to the surface of the foundation when completed4 ,it shall then be rolled with a road-roller weighing not less than ten 7#aj7 tons until the stone is thoroughly compacted4 ,the second course1 composed of screenings1 all of which shall have passed through a screen with openings one inch in diameter1 shall then be spread over the first course and well raked into the voids of the first course4 ,it shall then be thoroughly wetted1 and shall be rolled with the ten-ton roller until the fine stone is driven into the interstices of the first course and the whole thoroughly consolidated1 the wetting being repeated while the rolling continues4 ,additional screenings shall be added and rolled in where necessary to bring the surface to the proper elevation4 ,when completed1 the top surface of the foundation shall be 444 inches below1 and parallel to the pavement datum4 ,no part of the upper surface of the completed foundation shall project more than one-fourth 77 inch above1 nor shall it be more than one-half 77 inch below the grade and contour above specified4 ,gravel of a quality satisfactory to the ,engineer may with his written consent be substituted for broken stone4 ,if of assorted sizes1 such as will compress into a mass having not more than thirty 7#cj7 per cent4 of voids1 the foundation may be constructed in a single layer1 graded1 watered and rolled1 as prescribed above for broken stone4#ad #da4 ,measurement4--,broken stone and gravel foundation will be measured and computed by the cubic yard in the street as completed1 without any allowance for consolidation by the roller or for settlement into the sub-grade1 the thickness being taken as 444 inches4 ,the contract price for it shall cover the cost of supplying the material1 placing it on the street1 and grading1 watering and rolling it4 ,,sheet ,,asphalt ,,pavement ,note4--,a number of distinct varieties of asphalt are now used for asphalt pavements1 either alone or mixed4 ,these different varieties differ from each other quite widely in their physical and chemical properties4 ,thus1 in the form called 8refined asphalt0 some of their properties are shown by the following table1 the data for which is taken from the second edition of ,richardson's 8,the ,modern ,asphalt ,pavement40 ,,comparative ,,properties ,,of ,,different ,,refined ,,asphalts ,trinidad1 ,bermudez1 ,maracaibo1 ,calif4 ,gilsonite1 average average average of 8,d0 average of of two six grade1 two samples samples average samples of two samples ,softens1 degrees ,f4 #ahj #afe #bbe #acb #bhj ,flows1 degrees ,f4 #aij #age #bcf #aea #cjj ,penetration at #gh ,f4 #g #bd #ba #dh #j ,loss1 heated to #cbe #a4a #c4g #c4b #a4g #a4f for #g hours1 4 ,loss1 heated to #djj #d4j #h4h #e4e #g4a #b4f for #g hours1 4 ,bitumen soluble in #ef4e #ie4e #ic4i #ii4c #ii4d ,,cs#b4 ,inorganic1 other than #cf4e #b4b #b4i #j4c #j4e bitumen4 ,bitumen soluble in #ce4f #fe4f #ea4a #fi4f #dg4b naphtha4 ,bitumen sol4 in #ih4g #ii4j #ic4b #ie4g #ii4h carbon tetra-chloride4 ,fixed carbon4 #aj4h #ac4g #ag4b #ag4f #ac4b ,the practice has been heretofore1 and is at the present time1 to attempt to make specifications for asphalt pavements broad enough to include all the various varieties of asphalts1 under general requirements which shall admit these1 and any new varieties that may appear on the market suitable for the purpose1 the object being to permit a wide range of competition4 ,this makes it exceedingly difficult if not impossible to frame specifications that shall be sufficiently explicit and at the same time sufficiently broad to admit these several differing materials4 ,this practice has been adhered to in these specifications1 though in this respect they are far from satisfactory to the author4 ,so long as it continues to be the policy of cities to admit these various varieties of bitumen under the same general requirements for crude and refined material1 such objectionable specifications cannot be avoided4 ,even with the great latitude now provided they exclude some materials with which good pavements have been made4 ,two remedies for this unsatisfactory condition seem practicable4 #a4 ,a city might purchase a sufficient supply of refined asphalt for its use after asking for proposals under suitable specifications with alternative requirements for the different varieties on the market1 and after bids are received and the samples accompanying them have been properly examined in the laboratory1 award contracts for a supply of one or more kinds1 as might seem best for the interests of the city4 ,stocks of these would be delivered1 tested and stored accordingly1 in good time for the season's work4 ,specifications for construction with special reference to the kind of asphalt it is proposed to use could then be prepared1 the contractors to be supplied with asphalt at the city storage yard at a stipulated price per ton4 ,this plan would possess a number of advantages4 ,a similar plan is quite commonly in use with reference to hydraulic cement4 #b4 ,specifications might be framed with special reference to the properties and qualities to be possessed by the asphaltic cement1 permitting a liberal range as to the crude and refined bitumens to be used in manufacturing this cement4 ,this would be considered1 at the present time1 a radical departure from well established custom1 but the author sees no reason why it should not be satisfactorily employed4 ,a sheet asphalt pavement is composed of two essential elements2 a mineral aggregate made up of sand of assorted sizes and mineral 8dust0 and a bituminous cement4 ,when properly compounded1 manipulated and compressed these elements make up a bituminous concrete suitable for use as a wearing surface for streets and roads4 ,the character of the sand is important and we have now sufficient knowledge from experience to specify a sand that will give1 approximately1 the best results4 ,the bituminous cement is1 however1 the element of most importance1 and upon its suitability for the purpose depends very largely the utility and durability of the pavements made with it4 ,it is important that this asphaltic cement shall possess certain properties and qualities1 most of which we are now able to define satisfactorily1 but others require further practical and experimental study1 and some tests not now in use would doubtless be desirable4 ,it is not a matter of importance what particular crude or refined materials enter into the composition of this cement if the resulting product is satisfactory in use4 ,the prime requisite is a paving cement that shall possess in a high degree the chemical and physical qualities required for making an asphalt pavement of the best quality4 ,if we can devise standards and tests that will enable us to secure such a cement we need not be concerned about its antecedents4 ,it would be well worth while for paving engineers and those who have laboratory facilities to give attention to this matter4 ,if it shall be found practicable to define satisfactorily the qualities the cement should possess without reference to the materials from which it is compounded1 a great advance will have been made1 and our asphalt paving specifications could not only be greatly simplified1 but much greater precision and definiteness secured4 ,while great advances have been made in the art of building sheet asphalt pavements and in the framing of specifications for its construction1 too many of the specifications still in use are antiquated1 indefinite and unsatisfactory4 ,some of these contain requirements that1 if literally enforced1 would prevent the attainment of the best results4 ,they are largely survivals of the time when little was known either practically or technically of the science and art of constructing the pavements1 outside of the promoters and contractors in the business1 who consequently dictated1 in a large measure1 the specifications used4 ,city engineers were compelled to rely largely on the presumption that the guarantee clauses of the contracts would insure good results1 and allowed the contractor wide latitude in the conduct of the work4 ,while there is undoubtedly much yet to learn1 even by the experts1 in the matter of the materials to be used1 a quite satisfactory working basis has been arrived at1 particularly as to the practical side of the work1 and a large mass of data accumulated by study and experience is available to the municipal engineer1 and the services of independent experts is readily obtainable4 ,there is no longer any good reason1 therefore1 why the character of the materials to be used1 the methods followed1 and the quality of the work secured should not be quite definitely and fully specified in the same manner and to the same extent as in the case of other kinds of pavement and with equally satisfactory results4 ,,specifications #db4 ,general4--,asphalt pavement surface shall be laid upon a foundation of hydraulic cement concrete1 or of stone blocks relaid1 over a sub-grade1 to be constructed in accordance with ,articles #bf1 #bh1 #bi1 #cj1 #ca1 #cb1 #cc1 #cd1 #ce1 #cf and #cg4 ,asphalt pavement surface shall be constructed in two courses1 called the base-course and the surface-course4 ,the base-course may be from one 7#a7 inch to one and one-half 7#a7 inches thick1 and the surface-course may be from one 7#a7 inch to two 7#b7 inches thick1 as shall be hereafter specified4 #dc4 ,crude ,asphalt4--,the cementing element in asphalt pavements shall be prepared from crude native1 solid asphalts or from the proper distillation of crude asphaltic oils4 ,crude asphalts as obtained from the mines or natural deposits shall be properly refined to drive off water and to separate foreign substances1 by melting at a temperature not exceeding four hundred and fifty degrees ,f4 7#dej ,f474 ,crude asphalts of the quality commonly called 8glance pitch0 or 8iron pitch0 which do not distinctly soften at a temperature of two hundred degrees ,f4 7#bjj ,f471 and detached or deteriorated material from deposits otherwise acceptable will be rejected4 #dd4 ,refined ,asphalt4--,refined asphalt produced from native crude asphalt shall be free from water and shall not contain an injurious quantity of light oils or foreign matter4 ,it shall not contain more than four per cent4 7#d7 of organic matter nor more than thirty-six per cent4 7#cf7 of inorganic matter other than bitumen1 and not more than eighteen per cent4 7#ah7 of fixed carbon1 and not less than fifty-five per cent4 7#ee7 of bitumen soluble in cold carbon di-sulphide4 ,of the bitumen soluble in carbon di-sulphide not less than sixty-three per cent4 7#fc7 shall be soluble in ,pennsylvania petroleum naphtha of specific gravity eighty-eight 7#hh7 degrees ,baume at a temperature of sixty-five degrees ,fahrenheit 7#fe ,f47 and not less than ninety-eight per cent4 7#ih7 shall be soluble in chemically pure carbon tetra-chloride4 ,when exposed for seven hours to a temperature of three hundred and twenty-five degrees ,f4 7#cbe ,f47 in a shallow dish the bottom of which is covered with bitumen to a depth of three-fourths 77 inch1 the refined asphalt shall not lose more than five per cent4 7#e7 by evaporation4 ,asphalts that are injuriously affected1 in the pavement1 by water 7to be determined by the test immediately hereinafter described71 shall not be used except under the conditions specified in ,section #de4 ,cylinders made from the surface mixture it is proposed to use1 one 7#a7 inch in diameter and two 7#b7 inches long1 compressed to a density of two and one-tenth 7#b4a71 when immersed forty-five 7#de7 days in ten 7#aj7 times their volume of rain-water1 shall retain a sound surface1 unchanged and uncorroded by the action of the water4 ,refined asphalts resulting from the distillation of crude asphaltic oils will not be accepted unless the distillation shall have been effected by the use of suitable apparatus1 at a temperature not exceeding seven hundred 7#gjj7 degrees ,f4 ,the bitumen must not be over-distilled and 8cut back0 by adding oil4 ,the product1 to be acceptable1 shall possess the following qualities3 ,it shall melt and flow at a temperature not below one hundred and forty 7#adj7 degrees ,f41 but below a temperature of one hundred and eighty 7#ahj7 degrees ,f41 and when tested in the standard ,new ,york ,state closed oil-testing apparatus shall not flash at a temperature below four hundred and fifty 7#dej7 degrees ,f4 ,when exposed in a shallow dish1 the bottom of which is covered to a depth of three-fourths 77 inch with the bitumen1 to a temperature of four hundred 7#djj7 degrees ,f41 for seven 7#g7 hours1 it shall not lose by evaporation more than seven 7#g7 per cent4 by weight4 ,not less than ninety-eight 7#ih7 per cent4 shall be soluble in cold carbon di-sulphide1 and not less than sixty-five 7#fe7 per cent41 nor more than seventy-five 7#ge7 per cent4 of the bitumen shall be soluble in cold ,pennsylvania naphtha of gravity eighty-eight 7#hh7 degrees ,baume4 ,not less than ninety-nine 7#ii7 per cent4 of the bitumen shall be soluble in carbon tetra-chloride1 and it shall not contain more than sixteen 7#af7 per cent4 of fixed carbon4#ae ,bitumens resulting from destructive distillation or from artificial oxidation1 and bituminous compounds prepared from oil or oil residuums heated with sulphur or other substances1 or coal or gas tars1 will not be accepted1 nor shall they be mixed with the asphalt used4#af #de4 ,asphalts that are injuriously affected by water1 and those whose practical value for making pavements has not been established1 in the judgment of the ,city1 by sufficient experience1 will not be accepted except under such special bond and guaranty provisions as the ,city may prescribe4#ag #df4 ,full information as to the source and character of the crude asphalt and the method of refining it shall be furnished to the ,engineer and verified by such evidence as he may require4 #dg4 ,softening or ,tempering ,agent4--,for softening and tempering refined asphalt1 petroleum residuum oil or liquid asphalt shall be used4 ,it shall be free from water1 coke1 and other impurities4 ,its specific gravity shall not be below #j4ib1 nor above #a4jd4 ,its flash test 7determined in the standard ,new ,york ,state closed oil-testing apparatus7 shall not be under three hundred and fifty 7#cej7 degrees ,f41 and when exposed for seven 7#g7 hours to a temperature of three hundred and twenty-five 7#cbe7 degrees ,f41 in a shallow open dish1 the bottom of which is covered by the oil to a depth of three-fourths 77 inch1 it shall not lose more than five 7#e7 per cent4 by evaporation4 ,it shall not contain more than ten 7#aj7 per cent4 of paraffine scale4 #dh4 ,sand4--,a superior quality of sand will be required and this must be secured1 if necessary1 by the admixture of two or more sands4 ,the sand shall be silicious and so free from organic matter1 mica1 soft grains1 and other impurities1 that these shall not aggregate more than two 7#b7 per cent4 of the mass4 ,the grains shall1 preferably1 be moderately 8sharp0 or angular1 and must be of assorted sizes so that the voids in the compacted mass of dry sand shall not exceed thirty three 7#cc7 per cent4 ,a typical sand1 to be approximated as closely as practicable1 will give the following sieve tests1 the sieves being used in the order named3 #c per cent4 of the whole will pass ,no4 #bjj sieve4 #ae per cent4 of the whole will pass ,no4 #ajj sieve4 #ah per cent4 of the whole will pass ,no4 #hj sieve4 #cj per cent4 of the whole will pass ,no4 #ej sieve4 #bd per cent4 of the whole will pass ,no4 #cj sieve4 #aj per cent4 of the whole will pass ,no4 #aj sieve4 and none will fail to pass the ,no4 #aj sieve4#ah #di4 ,pulverized ,stone4--,this may consist of limestone or other sound stone or sand1 pulverized to such fineness that the whole will pass the ,no4 #ej sieve1 not more than ten 7#aj7 per cent4 will be retained on the ,no4 #ajj sieve1 and at least seventy 7#gj7 per cent4 of it will pass the ,no4 #bjj sieve4 ,portland cement may be partly substituted for pulverized stone1 where the ,engineer shall so direct4#ai ,portland cement thus used will be paid for at the price bid per barrel for the same1 in addition to the price paid per square yard for the pavement surface4 ,the pulverized material must be thoroughly dry when used4 #ej4 ,asphaltic ,paving ,cement4--,asphalt ,paving ,cement shall be prepared from the refined asphalt described in ,sect4 #dd and the tempering agent described in ,sect4 #dg4 ,the refined asphalt1 together with the asphalt in the tempering agent1 shall constitute not less than sixty per cent4 7#fj7 of the asphaltic cement4 ,the refined asphalt and the tempering agent shall be mixed and melted together at a temperature not below two hundred and seventy-five degrees ,f4 7#bge ,f471 and not above three hundred and twenty-five degrees ,fahrenheit 7#cbe ,f471 and thoroughly incorporated by agitation until a homogeneous cement is produced4 ,the agitation shall be continued until the cement is used4 ,the asphaltic cement at a temperature of seventy-seven degrees ,f4 7#gg ,f47 shall be of such consistency as to show a penetration of from forty to eighty hundredths of a centimeter1 as the engineer may direct for each street1 when tested with the standard ,dow penetration apparatus1 using a number two cambric needle loaded with one hundred grams4 ,when a cement of a consistency satisfactory to the engineer has been produced and approved for any street a sample of it shall be kept as a standard and all subsequent batches or kettles must be made to conform thereto1 suitable apparatus and tests being employed to determine the correspondence of each new batch with the standard4#bj ,the asphaltic cement when at its melting temperature shall be so viscous that it will draw out into moderately long fine threads which shall be free from lumps or raggedness and shall possess satisfactory adhesive and cementitious qualities4#ba #ea4 ,composition and ,preparation of ,asphalt ,surface ,mixture4--,the surface-course shall be composed of the materials specified in ,sections #dc1 #dd1 #de1 #df1 #dg1 #dh1 #di1 and #ej mixed in such ratios by weight as the ,engineer may direct or approve4 ,a typical mixture will contain3 ,sand #ajj4j lbs4 ,pulverized mineral matter passing ,no4 #bjj screen1 including that found in the paving cement #ag4e lbs4 ,pure bitumen 7in paving cement7 #ac4e lbs4 ,but the quantities of pulverized stone and of asphaltic cement shall be varied as may be found necessary or desirable by the ,engineer to suit the purity of the asphaltic cement1 the character of the sand1 the climatic conditions1 and the varying quantity and character of travel on the street to be paved2 and ,portland cement may be substituted partly or wholly for the pulverized stone1 when directed by the ,engineer4 ,the surface-course mixture shall be submitted to the ,engineer and approved by him before any is laid upon the street4 ,the mixing shall be accomplished in a mechanical mixing apparatus capable of rapidly and effectually incorporating the materials together1 and each batch must remain in the mixer a sufficient length of time to effect a perfect mixture4 ,the sand shall be separately heated and shall reach the mixing apparatus at a temperature not above three hundred and fifty 7#cej7 degrees ,f41 nor below three hundred and twenty 7#cbj7 degrees ,f4 ,the pulverized stone shall be at such a temperature that when mixed with the sand the temperature of the mixed mass shall not be above three hundred and fifty 7#cej7 degrees ,f41 nor below three hundred and twenty 7#cbj7 degrees ,f4 ,the sand shall be first placed in the mixer1 followed by the pulverized stone1 and these two materials shall be thoroughly mixed together before the asphaltic cement is added4 ,the asphaltic cement at a temperature not above three hundred and fifty 7#cej7 degrees1 nor below three hundred 7#cjj7 degrees ,f4 shall then be added in such a way as to evenly distribute it over the sand and pulverized stone1 and the mixing continued until the materials are thoroughly incorporated into a perfectly uniform and homogeneous mass1 with the grains of sand completely covered with cement4 ,suitable thermometers shall be constantly used to determine the temperatures specified herein4 ,great care must be taken to accurately weigh and proportion the materials charged into the mixer4#bb #eb4 ,stone for ,base-course4--,stone screenings for base-course shall be of crushed1 hard1 durable stone4 ,the portion used shall all be retained upon a ,no4 #h sieve1 or screen1 and shall all pass a screen having square meshes1 the linear dimensions of the openings in which are one-half 77 inch less than the thickness of the base-course4 #ec4 ,composition of ,base-course4--,the base-course shall be composed of the crushed stone specified in ,section #eb1 mixed with the asphaltic cement1 sand and pulverized stone specified in ,sections #ej1 #dh and #di1 but the asphaltic cement shall be of such hardness as the engineer may direct4 ,a typical base-course mixture will be composed as follows3 ,crushed stone #ajj lbs4 ,sand #db lbs4 ,pure bitumen 7in asphaltic cement7 #g lbs4 ,pulverized stone #g lbs4 ,but the mixture shall be such that when placed on the street and compressed by the roller the mass shall be dense and the voids in the stone completely filled2 and to accomplish this the quantity of crushed stone used in the mixture may be increased or decreased1 as the volume of its voids may require1 in order that they may be completely filled4#bc #ed4 ,mixing the ,base-course4--,the materials for the base-course shall be heated and mixed in the same general manner as prescribed for the surface-course 7,sect4 #ea71 the crushed stone being delivered first in the mixer4 ,the temperature of the mixture as it comes from the mixer being not above three hundred and twenty-five 7#cbe7 degrees ,f41 nor below three hundred 7#cjj7 degrees ,f4 #ee4 ,laying ,asphalt ,pavement1 ,general4--,asphalt pavement must not be laid except when the surface upon which it is to be placed is dry2 nor when the temperature of the air is below thirty-two 7#cb7 degrees ,f41 or1 if a strong wind prevails1 when the temperature of the air is below forty 7#dj7 degrees ,f4 ,the pavement mixture1 whether for base- or surface-course1 shall be taken to the street as soon after it leaves the mixer as practicable4 ,when the temperature of the air is below seventy 7#gj7 degrees ,f41 the loaded vehicles conveying the mixture to the street shall be covered by canvas covers to prevent the escape of heat4 ,when unloaded upon the street1 the temperature of the mass should not be below two hundred and eighty 7#bhj7 degrees ,f41 and any load or portions of a load found under two hundred and forty 7#bdj7 degrees ,f4 must be rejected4 ,after being unloaded on the street1 the mixture must be shoveled into place in such a manner that the whole of it will be moved from the pile into which it was unloaded4 #ef4 ,laying the ,base-course4--,the base-course will have an average thickness of one and one-quarter 7#a7 inches after compression4 ,it shall be laid directly upon the pavement foundation1 which must be free from all loose fragments and rubbish and be swept clean in advance of the application of the base-course4 ,the base-course mixture shall be spread upon the foundation and evenly and regularly graded to such a depth that after compression by the roller its surface will be 444 inches below1 and truly parallel to1 the pavement datum4 ,great care must be taken in handling1 spreading and grading the mixture to maintain the uniform admixture of the crushed stone throughout the mass4 ,the rakes used must have tines wide apart1 and the back of the rake must be principally used for grading4 ,immediately after being graded1 and while still hot1 the base-course shall be rolled with an asphalt roller weighing not less than five tons1 the rolling being continued until no further compression takes place4 ,the base-course must not be laid more than one day's work in advance of the surface-course4 ,when the base-course is completed it must present a uniform appearance and texture over the whole surface1 which must conform so truly to the designed grade and contour that a twelve-foot template1 when applied1 will show no departure from the true surface greater than one-quarter 77 inch4 #eg4 ,laying the ,surface-course4--,in delivering the surface-course mixture upon the base-course1 care must be taken not to break or disturb the latter4 ,any breaks made in the base-course must be so repaired1 before the surface-course is spread1 as to be equal in density and surface to the adjoining base4 ,before the surface-course is spread the base-course must be thoroughly cleaned and all rubbish1 loose material and street dirt removed4 ,the material for the surface-course shall be so evenly spread and graded with asphalt rakes that after it is properly compacted by rolling1 the surface will coincide with the pavement datum within the limits named below4 ,in grading the material1 all lumps must be broken up and the whole reduced to a finely comminuted mass of equal density throughout4 ,directly after being so graded it shall be rolled with a hand-roller1 or light steam-roller1 to partly compress the material1 and1 when so directed by the ,engineer1 the surface shall then be ironed with smoothing irons heated to a temperature that will melt1 but not burn1 the asphaltic cement4 ,a thin layer of hydraulic cement1 just sufficient to prevent adhesion between the material and the roller1 shall then be swept over the surface1 which shall at once be thoroughly rolled with a ten-ton asphalt roller until the material shall be thoroughly compressed and its surface be brought to the exact grade and contour designed for the street surface4 ,the work of the ten-ton steam-roller must begin before the material has cooled below two hundred 7#bjj7 degrees ,f41 and be continued until the roller makes no further impression upon the surface4 ,the first course of the heavy rolling shall be parallel to the street beginning at the curb and working toward the center on each side1 after which it should be diagonally rolled1 and also cross-rolled if the width of the street permits4#bd ,any portions of the surface not accessible to the roller shall be tamped with hot tampers until compacted equally with the rolled portion4 ,when completed1 the surface shall have an average thickness of 444 inches and must be so free from waves or irregularities that a template not less than twelve feet long1 when applied to the street surface shall nowhere show a divergence from the designed true surface of more than three-sixteenths 77 inch1 and a template sixteen 7#af7 feet long applied to the gutters shall show no divergence from the true gutter grade greater than one-eighth 77 inch4 ,before the surface-course is placed1 all exposed surfaces of curbs1 crosswalks1 manholes1 etc41 with which the surface-course will be in contact1 must be well painted with hot paving cement or approved pitch4 ,the street shall not be opened to travel until the pavement has become cold and hard4 #eh4 ,street ,railroad ,tracks4--,where railroad tracks exist on the streets1 the sub-grade and the pavement foundation shall extend under the tracks1 uninterrupted except by the ties and other structures connected with the track4 ,where concrete foundation is used1 special care must be taken with the concrete directly under or around the rails1 and concrete made of fine crushed stone and a higher ratio of cement and sand may be required in contact with the rail4 ,the concrete must be thoroughly tamped under and against the rail4 ,the asphalt surface shall be laid directly against the rails1 which1 if their temperature be under fifty 7#ej7 degrees ,f41 shall be heated by suitable appliances to a temperature of1 or above1 sixty 7#fj7 degrees ,f4 immediately before the asphalt material is placed around the rail4 ,the hot asphalt material must be thoroughly tamped against and along the rail and under any projecting portions of it1 and the surface of the pavement must be even with1 or slightly 7not more than one-eighth 77 inch7 above the top of the rail4 ,slot-rails will be treated in the same manner1 subject to such modifications as their forms may necessitate4#be #ei4 ,plant4--,the plant for making asphalt paving mixtures must be of approved modern design1 adapted to do the work properly1 and equipped with efficient machinery4 ,it shall be of sufficient capacity to turn out at least twelve hundred square yards of pavement surface daily without crowding4 ,weighing and measuring devices shall be accurate and adapted to the purpose1 and must be frequently tested and adjusted4 ,each plant must be supplied with the apparatus necessary to make all determinations and tests required at the plant to properly conduct the work in accordance with these specifications4 ,steam-rollers must be properly balanced and the rolling surface must be true and smooth4 ,all the street tools used must be of approved kind and quality and must be kept in good working order4 ,,asphalt ,,block ,,pavement #fj4 ,sub-grade4--,the sub-grade for asphalt block pavement shall be prepared as specified in ,sect4 #bf of these specifications4 #fa4 ,foundation4--,the foundation for asphalt block pavement shall be hydraulic concrete or broken stone4#bf ,concrete foundation shall be constructed in accordance with ,sections #bh to #cg inclusive of these specifications and shall have a thickness of 444 inches4 ,broken stone foundation shall be constructed in accordance with ,section #dj of these specifications and shall have a thickness1 when completed of 444 inches4 #fb4 ,asphalt ,blocks4--,asphalt blocks shall be not less than ten 7#aj7 inches nor more than twelve 7#ab7 inches long1 not less than four 7#d7 nor more than six 7#f7 inches wide and not less than two 7#b7 inches nor more than four 7#d7 inches thick4 ,blocks for the same street must be of the same standard size throughout and individual blocks shall not vary in any dimension more than three-sixteenths 77 inch from the standard size4 ,blocks that are chipped1 cracked or are otherwise defective shall be rejected4 #fc4 ,material and ,composition4--,asphalt paving blocks shall be composed of crushed trap rock#bg or equally hard and durable rock1 sand1 pulverized stone and asphaltic cement4 ,the crushed rock shall be of such sizes that all will pass a screen having circular openings one-third 77 inch in diameter and that all will fail to pass a number ten 7,no4 #aj7 sieve4 ,the stone shall be freshly crushed1 free from foreign substances and clean and bright4 ,the sand shall be clean and sharp and of such sizes that all will pass the number ten sieve and not more than five per cent4 will pass the number two hundred sieve4 ,the grain-size of the sand shall preferably be such that at least fifty per cent4 7#ej7 of it will pass the number eighty sieve4 ,the screenings from the crushed stone passing the number ten sieve may be used in place of sand1 or thoroughly mixed with the sand to produce a mass of the above composition4 ,the pulverized stone shall comply with ,section #di of these specifications4 ,portland cement shall be used in place of not more than ten per cent4 of the whole if directed by the engineer1 in which case the ,portland cement will be paid for as extra work at the prevailing market price4 ,the asphaltic cement shall comply with the requirements of ,sections #dc1 #dd1 #de1 #df1 #dg and #ej of these specifications4 #fd4 ,typical ,composition4--,a typical composition of the blocks1 which must be complied with as nearly as practicable1 is as follows2 7by weight7 ,bitumen #g ,mineral material passing ,no4 #bjj sieve #ac ,mineral material passing ,no4 #hj sieve #i ,mineral material passing ,no4 #dj sieve #g ,mineral material passing ,no4 #aj sieve #bh ,mineral material passing ,no4 #c sieve #cf -------- #ajj #fe4 ,manufacture4--,the crushed rock1 sand and pulverized stone shall be thoroughly mixed together at a temperature not above three hundred and seventy-five degrees ,fahrenheit 7#cge ,f47 and not below three hundred and twenty-five degrees ,fahrenheit 7#cbe ,f47 and the asphaltic cement1 at a like temperature1 added and the mixing continued until a perfectly uniform mass is produced1 with every fragment of stone completely coated with cement4 ,the hot mixture will then be compressed in molds under a pressure not less than four thousand 7#djjj7 pounds#bh per square inch1 after which the blocks will be removed from the molds and allowed to cool1 either in the air or in water4 ,the completed blocks after cooling in air shall have a specific gravity of not less than #b4e4 ,they shall not absorb1 when immersed in water for twenty-four hours1 more than one-half of one per cent4 of water4 ,when tested in the standard rattler for testing paving brick the average loss by abrasion shall not exceed twelve per cent4 7#ab7 of their original weight1 after #ahjj revolutions of the rattler4 #ff4 ,laying the ,blocks4#bi--,the foundation shall be first cleaned of dirt1 rubbish or loose material4 ,when the blocks are four 7#d7 inches or less in depth as laid1 they shall be set upon a bed of mortar made and applied to the foundation in the following manner3 ,the mortar shall be composed of ,portland cement and sand1 in the ratio of one 7#a7 part cement to three 7#c7 parts of sand1 thoroughly mixed with sufficient water to make a rather soft mortar4 ,this mortar shall be spread over the foundation1 which shall be previously wetted1 in a layer approximately one-half 77 inch thick and its top graded by the use of templates to a surface at such depth below1 and truly parallel to the pavement datum1 that when the blocks are firmly set in it and rammed their tops will be in the true grade and contour of the pavement4 ,the mortar shall be made and spread only as required in the progress of block laying1 and any mortar that has begun to set before the blocks are in place and rammed1 shall be removed and fresh mortar substituted4 ,the blocks shall be set upon this mortar bed with their longest dimension across the street1 in continuous courses which shall be straight and at right angles to the axis of the street4 ,the block layers must stand upon the blocks already laid and not upon the mortar4 ,the blocks and the courses of blocks shall be set as closely together as practicable4 ,blocks in adjoining courses must break joint not less than four inches4 ,whole blocks only will be used1 except as fillers at the ends of the courses or in fitting the pavement around manholes or other structures1 and where thus used the broken ends of the blocks must be dressed to make close joints4 ,unless otherwise permitted1 each course must be laid continuously across the street without interruption in time4 ,as each course is completed the end joints shall be forced close together by the use of wedges1 levers or mauls4 ,upon the completion of every third course1 the courses shall be forced together by placing a timber scantling against the face of the last course and striking it with a sledge or maul4 ,when the blocks are thus laid1 and before the mortar under them begins to set1 they shall be well rammed to a solid bearing in the mortar with a wooden street rammer weighing not less than thirty 7#cj7 pounds1 a two inch plank ten 7#aj7 inches wide and three 7#c7 feet long being interposed between the block and the rammer and moved about so that the whole surface shall be covered and rammed4 ,when the ramming is completed1 the top of the blocks must conform so closely to the pavement datum that when a template or straight-edge is placed upon the pavement1 its surface shall nowhere depart from the true surface more than three-sixteenths 77 inch4 ,blocks1 or portions of the pavement found too high or too low1 must be taken up and reset in fresh mortar to the true grade4 ,when thus completed to the satisfaction of the ,engineer1 a layer of one-half 77 inch of fine dry sand shall be placed over the surface and swept about with brooms until all joints are completely filled4 ,the remaining sand shall be removed from the pavement at such time as the ,engineer may direct4 ,when the depth of the blocks exceeds four 7#d7 inches1 they may be set upon a cushion course of sand1 as prescribed for brick pavement1 ,section #hf1 the joints to be filled with sand1 as specified above in this ,section4 #fg4 ,railroad ,tracks4--,where railroad tracks exist on the street to be paved1 the construction shall be the same as prescribed for granite block pavement1 ,section #gh4 #fh4 ,the street shall not be opened to travel until the mortar under the blocks shall have become fully set1 and in no case under five days after the blocks are laid4 ,,granite ,,block ,,pavement #fi4 ,granite block pavement shall be laid upon a foundation of hydraulic cement concrete4#cj #gj4 ,sub-grade and ,foundation4--,the sub-grade shall be prepared as specified in ,section #bf4 ,the foundation shall be constructed in accordance with the requirements of ,sections #bh to #ch inclusive4 #ga4 ,granite ,blocks4--,the blocks shall be made from sound1 durable granite1 of uniform texture1 composition and hardness throughout4 ,no outcrop1 deteriorated1 soft1 brittle1 or seamy stone shall be used4 ,if the blocks are obtained from different quarries1 or from different parts of the same quarry where the quality or appearance of the rock differs1 the product of each must be kept separate and laid together on the street4#ca ,the blocks shall be not less than eight 7#h7 nor more than twelve 7#ab7 inches long1 not less than three and one-half 7#c7 nor more than four and one-half 7#d7 inches wide1 and not less than four and three-quarters 7#d7 nor more than five and one-quarter 7#e7 inches deep4#cb ,they shall be well-shaped1 rectangular1 with full edges and corners4 ,their tops shall not depart more than one-fourth 77 inch from a true plane1 and their sides shall be dressed so that joints between the courses will nowhere exceed three-fourths 77 inch wide1 and their ends so that end joints shall not exceed one-half 77 inch wide4#cc ,the size of the blocks may be varied where necessary to fit the pavement against or around bridge stones or other street structures4 #gb4 ,sand ,cushion4--,the foundation shall be cleaned of all dirt and rubbish4 ,there shall then be spread evenly over it a layer of clean1 coarse sand to a uniform depth of one and one-half 7#a7 inches4 #gc4 ,setting the ,blocks4--,the blocks shall be set in this bed of sand perpendicular to the street surface1 with their length at right angles to the street1 in courses extending entirely across the street1 and at right angles to its axis1 except at street intersections where the courses shall be arranged as the ,engineer may direct4#cd ,only stones of the same width shall be set in the same course4 ,the stones in each course1 and in adjoining courses1 shall be set firmly against each other4 ,the blocks shall be set in the sand bed in such a manner that their bottom surface shall rest evenly upon the sand and that their tops shall be even with each other and to such an elevation that after the pavement is rammed1 as hereinafter directed1 its general surface shall conform closely to the pavement datum4 ,stones in adjoining courses shall break joint not less than three 7#c7 inches4 #gd4 ,ramming4#ce--;,after the blocks are set each individual block shall be thoroughly rammed to give it a firm bearing in the sand and to bring its top to the prescribed pavement datum4 ,the rammers used shall have wooden faces not more than four inches in diameter1 and shall weigh not less than thirty 7#cj7 pounds4 ,blocks or sections of blocks whose tops under the ramming remain above or sink below the pavement datum shall be taken up and reset so that after the ramming is completed their tops shall coincide with the pavement datum4 #ge4 ,filling the ,joints4#cf--;,after the ramming specified in ,sect4 #gd shall have been completed1 the joints between the paving blocks shall be filled in the following manner3 ,all the joints for a distance of three feet out from the curbstones1 and three contiguous joints continuous across the street1 with the included end joints1 at intervals of about fifty 7#ej7 feet in the length of the street1 shall be filled with gravel and bituminous paving cement4 ,the gravel used shall be of such size that all will pass through a screen having five-eighths 77 inch meshes1 and all will be held on a screen having one-fourth 77 inch meshes4 ,when used1 the gravel must be free from refuse and street dirt4 ,the bituminous paving cement shall be composed by weight of straight-run coal-tar pitch of the hardness commonly known as number six1 to which has been added and thoroughly mixed1 while both are in a melted condition1 twenty per cent4 7#bj7 by weight of refined ,trinidad asphalt1 or other asphalt1 equal for the purpose1 and twenty per cent4 7#bj7 by weight of ,portland cement4 ,these ingredients must be thoroughly mixed1 and kept agitated until used4#cg ,the joints will first be filled with the gravel1 which shall be perfectly dry1 and heated so that when put in the joints it will be at a temperature of about three hundred 7#cjj7 degrees ,f4 ,the paving cement1 heated to a temperature of about three hundred 7#cjj7 degrees ,f41 shall be at once1 while the gravel is still hot1 poured from a spouted vessel into the joints until the interstices of the gravel are entirely filled to the surface of the pavement1 repouring being resorted to to accomplish this result whenever necessary4 ,all the joints in the pavement other than those named above shall then be completely filled with ,portland cement grout1 in the following manner3 ,the grout shall be composed of equal parts by volume of sand 7,sect4 #cj7 and ,portland cement 7,sect4 #bi71 a quick-setting cement being preferred4 ,the sand and cement shall be first thoroughly mixed dry and then enough water added to make a grout of such consistency that it will flow like thick cream1 and the mixing continued until a homogeneous mass is produced and until the grout is applied to the pavement4 ,the grout shall be prepared in water-tight boxes of a convenient size4 ,before applying the grout the pavement shall be thoroughly dampened by sprinkling4 ,the grout shall be removed from the mixing box and spread over the pavement with scoop shovels1 in two courses1 the first being sufficient to about half fill the joints1 and the second1 which shall be applied before the first has begun to set1 shall be sufficient to entirely fill the remaining space in the joints4 ,as the grout is applied to the pavement it shall be swept about with brooms until it all enters the joints4 #gf4 ,order of ,work4--,the sand bed shall not be put in place more than fifty 7#ej7 feet ahead of the block setters4 ,the ramming and filling of the joints shall follow closely the block setting1 but no ramming shall be done within less than six 7#f7 feet of the face of the block setting2 and the final joint filling shall be kept completed to within twenty-five 7#be7 feet of the ramming2 except that all the work rammed during any day shall have the joint filling completed before the cessation of work on that day4 ,the street shall not be opened to travel until the grout has thoroughly set4 #gg4 ,fitting ,paving ,around ,other ,structures4--,the size of blocks and the width of courses shall1 as the block laying approaches bridge stones1 curbs and other structures1 or in making closures with other sections of pavement1 be so selected and adjusted that joints not over three-quarters 77 inch in width shall result1 without breaking blocks or splitting courses4 #gh4 ,street ,railroad ,tracks4--,where railroad tracks exist in the street the paving blocks shall be laid against the rail in the following manner3 ,the sub-grade and the pavement foundation shall extend under the rails uninterrupted except by the ties or other structures connected with the railroad track4 ,for a distance of sixteen 7#af7 inches1 on each side of the rail1 measuring from the center thereof1 there shall be spread on the pavement foundation a layer of mortar not less than one and one-half 7#a7 inches thick1 composed of one 7#a7 part of cement and three 7#c7 parts sand1 complying with the requirements of ,sections #bi and #cj4 ,upon this layer of mortar shall be set1 against the rail1 and on each side of it1 selected paving blocks1 securely bedded in the mortar before it shall have begun to set4#ch ,alternate blocks shall be long and short so as to break joint with the blocks of the adjoining pavement4 ,selected blocks with well dressed top surfaces shall be used and their tops shall be set as nearly as practicable at the level of the top of the rail1 but not so high that the car wheels will ride upon them4 ,in setting the blocks they shall be firmly bedded into the mortar by the use of paving hammers1 but they shall not be thereafter rammed4 ,as the blocks are set1 any space between the paving blocks and the web of the rail shall be filled with mortar of the quality described above4 ,the placing of these blocks shall not precede by more than ten 7#aj7 feet the block laying on the street4 ,care must be taken not to disturb the bedding of these blocks in the laying of the adjoining pavement1 or otherwise4 ,the joints shall be filled with grout as specified in ,sect4 #ge4 ,the construction along slot-rails shall be the same as described above1 except that blocks of special size or shape may be required1 as the ,engineer may direct4 #gi4 ,bridge ,stone ,crossings4--,where directed by the ,engineer1 the old bridge stone shall be redressed and relaid1 as hereinafter specified for new bridge stone1 and shall be moved from the point where taken up to the point where they are to be relaid1 by the ,contractor at his expense4 ,new bridge stone shall be of the same quality of granite as the paving blocks and free from imperfections4 ,they shall not be less than three and one-half 7#c7 nor more than six 7#f7 feet long1 eighteen 7#ah7 inches wide and of a uniform thickness not less than six 7#f7 nor more than eight 7#h7 inches1 but these dimensions may be varied by the ,engineer where necessary to fit the stone into special locations4 ,their top shall be well dressed to a true plane surface not varying in evenness more than one-quarter 77 inch4 ,the sides shall be dressed perpendicular to the face so as to joint closely against the paving blocks4 ,the ends shall be cut to lines making an angle of from #fj to #de with the longitudinal axis of the stones#ci and so dressed and to such a bevel that when set in the curved surface of the street1 the joint between adjoining stones shall not be wider than three-eighths 77 inch from top to bottom4 ,bridge stones shall be set in advance of the block laying1 over the concrete street foundation1 in a bed of sand or gravel in which they shall be firmly bedded4 ,their upper surface shall conform truly to the pavement datum4 ,they shall be set accurately to the lines given by the ,engineer4 ,where the crosswalk requires more than one width of bridge stone1 the courses shall be laid parallel to1 and at such distance from each other as the ,engineer may direct1 and the space between courses shall be filled with paving blocks laid as specified for other parts of the street4 ,,brick ,,pavement#dj #hj4 ,sub-grade4--,the sub-grade for brick pavement shall be prepared in accordance with ,sect4 #bf1 and shall be finished to a surface 444 inches below and parallel to the pavement datum4 #ha4 ,foundation4--,the foundation for brick pavement shall be of hydraulic concrete#da prepared in accordance with ,sections #bh to #cg inclusive4 ,its thickness shall be 444 inches and its upper surface shall1 when completed1 be parallel to and at a depth below the pavement datum equal to the depth of the brick plus one and one-fourth 7#a7 inches4 ,the surface of the foundation shall not vary more than one-half 77 inch above or below that depth4 #hb4 ,paving ,brick4--,the linear dimensions of paving brick may vary between the following limits3 ,in length1 from eight and one-half 7#h7 to nine and one-half 7#i7 inches2 in width1 from two and one-fourth 7#b7 to three and one-half 7#c7 inches2 in depth1 from four 7#d7 to four and one-eighth 7#d7 inches2 but the length shall not be less than two and one-half 7#b7 nor more than three and three-fourths 7#c7 times the width4#db ,the corners shall all be rounded off to a radius of not less than one-eighth 77 nor more than three-sixteenths 77 inch4 ,the brick for any one contract shall be all of the same kind and of the same standard size1 and the individual bricks shall not vary in length more than three-sixteenths 77 inch1 nor in width more than one-eighth 77 inch from the size adopted as standard4 ,raised lugs or letters are permissible on one side of each brick but must not project more than three-sixteenths 77 inch from the general surface4#dc ,the brick must be specially manufactured for paving purposes4 ,they may be made from shale or from suitable clay4 ,in either case the material must be thoroughly pulverized1 mixed and tempered1 and must be free from lime nodules or other substances that may disintegrate the brick when immersed in water4 ,the brick shall be molded in efficient brick machines to a truly rectangular form1 free from cracks1 flaws and injurious laminations4 ,after being dried the brick shall be properly and uniformly burned in down-draft kilns4 ,shale brick shall be burned to the point of incipient fusion or vitrification4 ,after the burning is completed1 the brick shall be allowed to cool with sufficient slowness to insure thorough annealing4 ,the completed brick shall be free from flaws1 cracks1 ragged corners1 and from such distortion or warping as will interfere with their utility or good appearance in the pavement4 ,paving brick shall not be salt-glazed4 #hc4 ,the brick shall be subjected to the following tests to determine their quality3 ,when broken by the blows of a hammer the brick shall be strong and tough4 ,the broken surface shall show a homogeneous composition throughout the broken section1 free from flaws1 injurious laminations1 nodules and voids1 and shall appear to be uniformly burned from surface to center4 ,when subjected to the standard 8,rattler0 test1 in accordance with the rules adopted by the ,national ,paving ,brick ,manufacturers' ,association1 the average loss in weight shall not exceed eighteen 7#ah7 per cent4#dd and the loss in weight of any individual brick in the test shall not be more than twenty-five 7#be7 per cent4 greater than the average loss of the whole charge4 ,when subjected to the absorption test1 in accordance with the rules adopted by the ,national ,paving ,brick ,manufacturers' ,association1 shale bricks shall not absorb more than two 7#b7 per cent4 nor less than one-half 77 of one per cent4 of their weight of water1#de and clay bricks shall not absorb more than six 7#f7 per cent4 of their weight of water2 the absorption of any individual brick shall not be more than fifty 7#ej7 per cent4 greater than the mean absorption of the whole lot tested4#df ,brick that do not successfully pass all these tests will not be accepted4 #hd4 ,samples4--,where samples of paving brick have been required and submitted by successful bidders1 and tested as described above1 it will be assumed that these samples fairly represent the quality of the brick to be subsequently supplied for the work1 and brick that do not come up to the standard thus established will not be accepted4 #he4 ,delivering ,brick on ,street4--,unless the sidewalks are too narrow to permit of it1 the brick shall all be delivered upon the street before the foundation is constructed1 and neatly piled upon the outer edge of the sidewalks2 occasional openings being left in the piles for the accommodation of foot passengers4 ,one-half the brick required shall be thus delivered and piled upon each sidewalk4 ,in delivering the bricks from these piles to the bricklayers1 they must be carried on pallets1 or other suitable devices must be used to prevent mutilation by rough handling2 they must not be dumped from wheelbarrows upon freshly-laid brick pavement4 ,if for any reason the bricks are not delivered before the foundation is laid1 or if the sidewalks are too narrow to permit of the brick being stored upon them1 they may be delivered over the foundation1 but not until the concrete has set so hard that it will not be injured by transportation over it4 #hf4 ,sand ,cushion4--,directly before the brick are laid into the pavement there shall be spread over the foundation a layer of sand one and one-half 7#a7 inches in depth4 ,the sand shall be free from vegetable or other refuse matter1 and shall not contain more than five 7#e7 per cent4 of clay and loam4 ,pebbles and fragments of stone exceeding one-fourth inch in diameter must be screened out4 ,when spread on the street the sand shall be sufficiently dry to permit of proper gaging by templates1 as hereinafter described4 ,the sand shall be spread and correctly gaged to the proper thickness and surface by the use of templates formed to the true designed cross-sectional contour of the pavement4 ,if the width of the street between curbs does not exceed twenty-five 7#be7 feet1 the template shall be made in one length sufficient to cover the full width of the street1 and its ends shall be so constructed and fitted with iron rollers1 that it will rest upon and roll along the top of the curb at each end2 if the width of the street between curbs be not more than fifty 7#ej7 feet1 the template shall be of sufficient length to reach from the curb to the middle of the street1 and constructed to move on rollers on top of the curb at one end and upon a plank six 7#f7 inches wide and one and one-half 7#a7 inches thick laid upon the foundation along the center line of the pavement4 ,the template shall be worked forward and backward along the line of the street until the surface of the sand conforms exactly to the designed contour of the pavement1 at a depth below the pavement datum equal to the depth of the paving brick minus one-fourth 77 inch4 ,the whole surface shall then be rolled with a garden roller not less than thirty-six inches long and not less than thirty inches in diameter1 weighing not less than three hundred pounds4 ,when completed the surface of the sand cushion shall be smooth and unbroken1 and care must be taken not to disturb it before the bricks are set upon it4 #hg4 ,setting the ,brick4--,several courses of brick1 aggregating a strip having a width of not less than twelve 7#ab7 inches nor more than fifteen 7#ae7 inches on each side of the street1 beginning against the curb1 shall be first laid2 the brick being set with their long dimension parallel to the curb4#dg ,the pavement intervening between these gutter courses will then be set in courses at right angles to the axis of the street1 except in street intersections1 where the courses shall make an angle of forty-five 7#de7 degrees with the axis of the street4 ,the brick shall be set upon edge on the sand cushion with their top faces parallel to the pavement datum1 in straight courses1 continuous across the street1 the long dimension of the brick being parallel to the courses2 they shall be set as closely together as possible1 so that the joints both between the courses and between individual bricks shall not exceed one-eighth 77 inch1 where the bricks are without lugs1 and not more than one-fourth inch where the brick have lugs4 ,broken bricks and bats shall not be used except as closers at the ends of the course and in fitting the pavement around manholes1 etc41 and nothing smaller than half-bricks shall be used in either case1 and the broken ends must be shaped to make reasonably close joints4 ,filling up with bats must follow the brick-laying closely4 ,brick with lugs shall be laid with the lugs all in one direction4 #hh4 ,inspection4--,after the bricks are laid the pavement will be inspected by the ,engineer1 or his agent4 ,he may require that the surface shall be previously wetted by sprinklers1 or by a sprinkling nozzle1 in order to detect soft or porous bricks4#dh ,defective bricks indicated by him shall be removed and replaced by acceptable brick4 #hi4 ,rolling and ,ramming4--,the surface of the pavement shall then be rolled and rammed in the following manner3 ,the roller used shall be of the asphalt roller style1 driven by steam and weighing not less than three and one-half 7#c7 nor more than five 7#e7 tons4 ,the rolling shall begin as near the curb as practicable1 the roller being operated slowly1 parallel to the axis of the street1 and working outwardly until the center of the street is reached1 when the roller will proceed to the opposite side of the street and the operation proceed as before4 ,after this longitudinal rolling is completed the pavement will be continuously rolled a second time1 the roller operating back and forth at an angle of forty-five degrees to the axis of the street1 and a third time1 the roller operating at right angles to the course of the second rolling4 ,after the rolling is thus completed the brick in the gutters not reached by the roller shall be rammed with a street rammer weighing not less than thirty 7#cj7 pounds1 a plank not less than four 7#d7 feet long1 ten 7#aj7 to twelve 7#ab7 inches wide and two 7#b7 inches thick being interposed between the pavement and the rammer and moved about so that the whole surface of the gutter shall be thoroughly and equally rammed and its surface brought to an even junction with the rolled portion of the work4 ,when the rolling and ramming is thus completed the surface of the pavement shall conform so truly to the designed pavement datum that it will nowhere depart more than three-sixteenths 77 inch from properly formed templates and straight-edges applied to its surface4 #ij4 ,filling the ,joints4#di--;,directly after the completion of the rolling and ramming1 the joints between the bricks shall be filled as follows3 ,the joints in the longitudinal gutter courses1 and the joints between six contiguous courses running across the street1 from gutter to gutter1 in each length of fifty 7#ej7 feet of the pavement1 shall be filled with bituminous cement composed of coal-tar pitch1 commercially known as ,number ,four1 to which has been added twenty 7#bj7 per cent4 of refined ,trinidad asphalt and twenty 7#bj7 per cent4 of hydraulic cement1 all by weight4 ,in preparing this bituminous cement1 the pitch shall first be melted and the asphalt1 also melted1 added and thoroughly incorporated by agitation4 ,the hydraulic cement shall then be added and the whole agitated until a complete and uniform mixture results4 ,the bituminous cement thus prepared shall while sufficiently hot and liquid to flow freely1 be poured from a spouted vessel into the joints until they appear to be nearly or quite full4 ,after allowing time for the filling to subside1 the joints will be gone over a second time and completely filled4 ,all the remaining joints in the pavement shall be filled with ,portland cement grout1 as follows3 ,the grout will be composed of equal parts by volume of sand 7,sect4 #cj7 and ,portland cement 7,sect4 #bi71 a quick-setting cement being preferred4 ,the sand and cement shall be first thoroughly mixed dry and then enough water added to make a grout of such consistency that it will flow like thick cream1 and the mixing continued until a homogeneous mass is produced and until the grout is applied to the pavement4 ,the grout shall be prepared in water-tight boxes of a convenient size4 ,before applying the grout the pavement shall be thoroughly dampened by sprinkling4 ,the grout shall be spread over the pavement with scoop shovels1 in two courses1 the first being sufficient to nearly fill the joints1 and the second1 which shall be applied before the first has begun to set1 shall be sufficient to entirely fill the remaining space in the joints4 ,as rapidly as the grout is applied it shall be swept with brooms until it all enters the joints4#ej #ia4 ,travel must be excluded from the pavement until the grout has set firmly2 in no case less than five days1 and the grout must be kept moist during this period4 ,,wood-,,block ,,pavement #ib4 ,sub-grade4--,the sub-grade for wood-block pavement shall be prepared as specified in ,section #bf1 and shall be finished to a surface 444 inches below the pavement datum4 #ic4 ,foundation4--,the foundation for wood-block pavement shall be ,portland cement concrete 444 inches thick1 prepared as specified in ,sections #bh1 #bi1 #cj1 #ca1 #cb1 #cc1 #cd1 #ce1 #cf and #cg4 ,the upper surface of the concrete foundation1 when completed1 shall be at a distance below the pavement datum equal to the depth of the blocks to be laid1 plus one-half 77 inch1 and must not vary more than one-fourth 77 inch above or below that depth4 ,,materials #id4 ,wood-blocks4--,the wood-blocks may be made of ,long-leaved yellow pine 7,pinus palustrus71 ,lob-lolly pine 7,pinus tda71 ,short-leaved pine 7,pinus echinata71 ,cuba pine 7,pinus heterophylla71 ,black gum 7,nyssa sylvatica71 ,red gum 7,liquidambar styraciflua71 ,norway pine 7,pinus resinosa71 or ,tamarack 7,larix laricina71 or of other species of wood of equal strength and toughness and of a texture permitting as satisfactory preservative treatment as those herein named4 ,but1 as far as practicable1 only one species of wood shall be used on any one contract4#ea ,only wood from live1 sound trees shall be used4 ,the lumber from which the blocks are cut shall be properly manufactured1 free from bark1 and with full square corners4 ,it shall be free from decay1 dottiness1 brashness1 shakes1 large season cracks1 loose or unsound knots over three-fourths 77 inch in diameter1 and all other imperfections which may1 in the opinion of the ,engineer1 be detrimental4 8,fat0 pine containing so much resin that it will not take up the specified quantity of creosote oil in treatment may be rejected4 ,second-growth timber1 and ,southern pine showing1 outside of a radius of three 7#c7 inches from the heart1 nine 7#i7 or less annual growth rings to the inch1 will not be accepted4 ,the paving blocks made from the lumber hereinbefore specified shall be well manufactured and truly rectangular and square edged4 ,their depth 7parallel to the fiber7 shall be 444 inches1#eb their length shall not be less than six inches nor more than three times their depth1 and their width shall be from two and one-half 7#b7 to three and one-half 7#c7 inches1 but at least one-fourth inch less than their depth4 ,all the blocks for any one contract shall be of the same standard depth and width1 and the individual blocks shall not vary more than one-eighth inch from the designated depth and width4 #ie4 ,creosote ,oil4#ec--,the oil used for the preservative treatment of the paving blocks shall be coal-tar creosote oil1 commonly known as dead oil of coal-tar1 without admixture or adulteration with other oils or tars4 ,oils produced or resulting from the distillation of water-gas tar1 blast-furnace tar1 producer-tar1 lignite-tar1 petroleum-oil tar1 or wood-tar1 or1 containing an admixture of any of these will not be accepted4 ,the creosote oil shall not contain more than five per cent4 7#e7 of tarry matter nor more than two per cent4 7#b7 of water4 ,its specific gravity at a temperature of #ajj ,f4 shall be not below #a4jc nor above #a4jh4 ,not less than ninety-nine per cent4 7#ii7 shall be soluble in hot benzol4 ,it shall not contain more than eight per cent4 7#h7 of tar acids4 ,when two hundred 7#bjj7 grams are subjected to distillation at gradually increasing temperatures1 not more than five per cent4 7#e7 of distillate shall distil over up to a temperature of four hundred degrees ,f4 7#djj ,f471 nor more than thirty-five per cent4 7#ce7 shall distil over up to a temperature of four hundred and fifty-five degrees ,f4 7#dee ,f471 and not more than eighty per cent4 7#hj7 shall distil over up to a temperature of six hundred degrees ,f4 7#fjj ,f474 ,after complete distillation there shall not remain more than two per cent4 of coke4 ,the residue remaining1 upon sulphonating a portion of the total distillate1 shall not exceed one per cent4 7#a74 ,the above tests shall be made in accordance with the methods prescribed in the 8,report of the ,committee on ,preservative ,treatment of ,poles and ,cross-arms0 of the ,national ,electric ,light ,association1 #aiaa4 #if4 ,preservative ,treatment4--,the paving blocks shall1 after they are cut to the proper dimensions1 be subjected to preservative treatment with the creosote oil specified in ,section #ie4 ,the contractor may employ any of the standard methods in common use for impregnating the blocks1 provided that uniform results are attained1 complying with the following requirements3 ,the wood shall not be heated during any part of the process to a temperature exceeding two hundred and sixty degrees ,fahrenheit 7#bfj ,f474 ,all parts of every block shall be reached and penetrated by the oil4 ,the quantity of oil found in the blocks after treatment shall average not less than 444 pounds per cubic foot of wood4 ,the oil in the treating tanks during the process of impregnation shall not become diluted with water to the extent of more than five per cent4 7#e7 and if the percentage of water in the oil during the process of treatment shall exceed two per cent4 7#b7 the quantity of the oil to be injected in the wood as stipulated hereinbefore shall be increased in a like ratio2 for example1 if the oil in the treating tanks shall be found to contain four per cent4 7#d7 of water the quantity required to be found in the blocks after treatment shall be four per cent4 7#d7 greater than herein specified4 ,the quantity of oil injected shall be determined primarily by tank measurements1 but shall be verified by actual determination of the quantity of oil in the treated blocks by the following method3 representative treated sample blocks shall be selected and an auger hole one inch in diameter bored entirely through the block parallel to the fiber1 the borings all collected1 thoroughly mixed1 and the quantity and ratio of oil to wood in the borings determined by extracting the oil completely with carbon di-sulphide4 ,the center of the auger hole shall be located midway between the sides of the block and at a distance from the end of the block equal to one-third 77 of the length of the block4 ,at the time of treatment the blocks shall not be green or saturated with water1 but they shall1 preferably1 not be thoroughly seasoned4 ,after treatment1 and until used1 the blocks shall1 during dry weather1 be frequently well drenched with water to prevent excessive drying out and cracking4 #ig4 ,laying the ,wood-,blocks4--,the concrete foundation shall be cleaned and swept to remove all dirt and dbris and shall be thoroughly dampened immediately in advance of the setting of the blocks4 ,upon the concrete foundation shall be spread a layer of mortar about one-half inch thick1 made of one part ,portland cement and two parts sand with sufficient water to make a moderately stiff paste4#ed ,the mortar shall be thoroughly mixed and shall be spread in place over the concrete foundation immediately in advance of setting the blocks to such a thickness that when the blocks are set and properly tamped their tops shall conform accurately to the pavement datum4 ,upon this mortar bed the blocks shall be set with their fiber vertical1 in straight1 parallel courses at right angles to the axis of the street1 except at street intersections where they shall be set at an angle of forty-five degrees with the axis of the street4 ,the blocks shall be set as close together as practicable4 ,blocks in adjoining courses shall break joint at least three inches4 ,blocks of such lengths shall be selected as to make as little splitting as practicable in filling out ends of courses4 ,where splitting is necessary1 no fractional block shall be used whose length is not at least equal to its width4 ,after the blocks are thus set the whole surface of the pavement shall be rammed with a rammer weighing not less than twenty pounds1 a plank ten 7#aj7 inches wide1 two 7#b7 inches thick and four feet long being interposed between the rammer and the pavement and moved about as the ramming progresses until the blocks are forced into a firm seat in the mortar bed and their tops brought accurately to the pavement datum4 ,the ramming shall be completed before the mortar under them has begun to set1 but no ramming shall be done1 during the progress of the work1 nearer than three feet to the edge of the block setting1 except where the block setting may be suspended1 as at the end of the day's work1 when all the blocks then set shall be rammed4 ,the top surface of the pavement when completed shall conform so truly to the pavement datum that correctly formed templates twelve 7#ab7 feet long applied to the surface shall show at no place a departure of more than three-sixteenths 77 inch therefrom4 #ih4 ,filling the ,joints4--,after the block setting is completed1 perfectly dry1 fine sand shall be spread over the pavement surface and swept about until every joint into which the sand will penetrate shall be completely filled4 ,the remaining sand shall be left upon the pavement for such time as the ,engineer may direct1 when it shall be removed by the ,contractor4#ee #ii4 ,inspection4--,the lumber for paving blocks will be inspected before it is cut into blocks4 ,the blocks will also be inspected upon delivery to the street and as they are laid4 ,blocks that have1 in treatment or subsequent handling1 developed open season cracks or wind shakes or other imperfections that may prevent their durability or usefulness in the pavement shall be rejected and removed from the street4 #ajj4 ,chamfered ,blocks4--,where wood-block pavement is laid on streets or parts of streets having a gradient of more than #c1 the blocks shall not be less than four 7#d7 inches long1 and the upper side-corners of the blocks shall be chamfered to a depth of three-eighths 77 inch1 the chamfered surface to make an angle of #dj degrees with the vertical sides of the blocks2 or such other construction shall be used as will1 in the opinion of the ,engineer1 provide an equally good foot-hold for horses4 #aja4 ,expansion ,joints4--,before the blocks are set there shall be placed along and against each curb a board of trapezoidal section having a width one inch greater than the depth of the blocks1 the upper edge of which shall have a thickness of three-eighths 77 inch for each ten feet or fraction thereof of the width of the street between curbs1 and a bottom width one-fourth 77 inch less than the top4 ,the paving blocks at the beginning and end of each course shall be set against this board4 ,after the ramming of the blocks has been completed1 these boards shall be carefully withdrawn and the space between the curbs and the paving blocks shall be completely filled with the bituminous paving cement described in ,section #ij4 #ajb4 ,the street shall not be opened to travel until such time as the mortar under the blocks shall have become well set1 nor until the ,engineer shall so direct4 ,,bituminous ,,concrete ,,pavement ,note4--,the phrase1 ,bituminous ,concrete ,pavement1 has been applied to a large variety of roadway surfaces differing materially from each other in composition1 construction and utility4 ,some of these are covered by ,united ,states patents1 the scope and limitations of which are not yet fully determined or understood4 ,the necessity of avoiding infringement of these patents has to be kept in mind in framing specifications for public use1 and this consideration does not permit the presentation here of specifications which1 in the opinion of the author1 would secure an ideal pavement of this general character4 ,bituminous concrete pavements constructed in substantial conformity with these specifications have been laid on a number of city and town streets and country roads and have proved satisfactory and fairly durable in use4 ,it is believed that they do not infringe any existing patents4 ,our rather limited experience with pavements of this character seems to indicate that if good materials are used and the work properly done1 they are suitable for use on city streets of light travel1 and on suburban streets and country roads carrying an amount of travel considered heavy for these classes of roadways4 ,where the results have been unsatisfactory1 the cause can generally be traced to unsuitable materials or unskillful construction1 the result of ignorance or carelessness on the one hand1 or of the attempt to reduce first cost below normal figures on the other4 ,many people are searching for a pavement or roadway that will have all the good qualities of the standard pavements but can be built about as cheaply as a common macadam road4 ,it is possible that something of the kind may be discovered2 but in the present state of the art it is chimerical4 ,high quality and low first cost do not go together in street paving4 ,the question to be considered is1 rather1 how can we invest a dollar in street or road building so that it will1 in the long run1 yield the best return upon the investment4 ,the pavement provided for in these specifications is not a cheap pavement1 but where it is suitable for the conditions to be met1 it will be well worth its cost4 ,,specifications #ajc4 ,sub-grade4--,the sub-grade except where old pavement is utilized for foundation shall be prepared in accordance with ,section #bf of these general specifications4 #ajd4 ,foundation4#ef--,the foundation for bituminous concrete pavement shall be a properly prepared old pavement1 or hydraulic concrete1 or compressed broken stone1 as determined by the engineer4 #aje4 ,old macadam pavement or road to be utilized for foundation1 shall be prepared in the following manner3 ,all high places or humps shall be dressed down to a plane two 7#b7 inches below the pavement datum1 the work being done with care so as to disturb as little as possible the macadam that is to remain4 ,depressions in the old macadam shall be carefully cleaned out so as to remove all earth and other dbris and loose material1 and filled with hydraulic concrete4 ,newly dug or filled trenches and holes extending through the macadam shall be excavated and cleaned out so as to admit the use of at least four 7#d7 inches of hydraulic concrete4 ,the hydraulic concrete for thus leveling up the roadway shall be composed of one 7#a7 part of approved ,portland cement1 four 7#d7 parts of clean sand and nine 7#i7 parts of sound1 hard crushed stone1 well mixed into a wet concrete4 ,after placing1 the concrete shall be well tamped so as to form a compact body1 conforming to a plane two 7#b7 inches below the pavement datum4 ,the concrete shall be protected from travel and allowed to become well set before the surface of bituminous concrete is applied4 #ajf4 ,old stone block or brick pavement may be utilized for foundation1 provided that the blocks or bricks do not require to be taken up and reset1 or1 if so taken up and reset1 that the joints shall be completely filled with grout composed of one 7#a7 part ,portland cement and two 7#b7 parts of good sand4 ,depressions1 trenches and holes shall be treated as specified in ,section #aje4 #ajg4 ,hydraulic concrete foundation shall be constructed in compliance with the requirements of ,sections #bh1 #bi1 #cj1 #ca1 #cb1 #cc1 #cd1 #ce1 #cf and #cg of these specifications4 ,its depth or thickness shall be 444 inches4 #ajh4 ,broken stone foundation shall be 444 inches in thickness after completion4 ,it shall be constructed in accordance with ,section #dj of these specifications4#eg #aji4 ,when completed the upper surface of the foundation shall nowhere be more than two and one-half 7#b7 inches nor less than one and three-fourths 7#a7 inches below the pavement datum4 ,no travel shall be permitted upon the foundation until the bituminous concrete shall have been laid4 #aaj4 ,bituminous ,concrete4--,the bituminous concrete shall be composed of crushed stone1 sand1 pulverized stone1 and asphaltic cement4 ,a typical composition for the bituminous concrete1 to be as closely approximated as practicable1 is as follows1 the percentages being by weight3 ,pure bitumen in asphaltic cement4 #h4e ,pulverized stone passing ,no4 #bjj sieve4 #h4e ,sand passing ,no4 #hj sieve4 #aj4j ,sand passing ,no4 #dj sieve4 #bc4j ,sand and fine stone passing ,no4 #aj sieve4 #ae4j ,crushed stone passing a screen having four meshes to the linear inch4 #be4j ,crushed stone passing a screen having two meshes to the linear inch4 #aj4j ------------ #ajj4j ,the crushed stone shall be trap rock1 granite1 or hard1 sound1 durable limestone4 ,it shall be crushed to such sizes that all will pass through a screen with two meshes to the linear inch and shall be of such assorted sizes of fragments as will1 when incorporated with the sand1 pulverized stone1 and bitumen1 produce a mixture substantially conforming to the percentages of each named in the preceding paragraph4 ,the stone shall be freshly crushed1 clean and free from clay1 loam1 organic matter and refuse of every kind4 ,the sand shall be silicious1 and free from clay1 loam and refuse of all kinds4 ,the grains shall be of such sizes that approximately twenty-five per cent4 7#be7 of the whole will pass the number eighty 7#hj7 sieve1 fifty-eight per cent4 7#eh7 shall pass the ,no4 #dj sieve and not more than seventeen per cent4 7#ag7 will pass the number #aj sieve1 when used in the order named4 ,the pulverized stone shall conform to the requirements of ,sect4 #di4 ,portland ,cement may be substituted for not more than twenty per cent4 7#bj7 of the pulverized stone if the ,engineer so directs1 in which case the ,portland ,cement actually so used shall be paid for extra at the prevailing market price1 to be agreed upon in advance4 ,the asphaltic cement shall comply with the requirements of ,sects4 #dc1 #dd1 #de1 #df1 #dg1 and #ej1 except that it may have a somewhat higher penetration1 as may be determined by the ,engineer4#eh #aaa4 ,mixing4--,the materials composing the concrete shall all 7except the pulverized stone and ,portland cement7 be uniformly heated to a temperature not exceeding three hundred and fifty degrees ,fahrenheit 7#cej ,f47 and not below three hundred degrees ,fahrenheit 7#cjj ,f471 and while at such temperature shall be incorporated and mixed in a mechanical mixer4 ,the stone1 sand1 and pulverized stone shall be placed in the mixer in the order named and well mixed together1 after which the asphaltic cement shall be added and the mixing continued until each fragment is thoroughly coated with cement4 #aab4 ,laying on the ,street4--,the mixed concrete shall be taken to the street as soon as practicable after leaving the mixer4 ,it shall be unloaded on the street1 properly spread and truly graded with asphalt rakes to such a depth that after compression by rolling it will have a thickness of not less than two inches4 ,the concrete when unloaded on the street shall be at a temperature not below two hundred and eighty degrees ,fahrenheit 7#bhj ,f474 ,in spreading and grading1 all material must be moved from the pile into which it was unloaded4 ,as soon as practicable after the concrete shall be graded1 the surface shall be thoroughly rolled with a ten-ton asphalt roller and the rolling continued until the roller makes no further impression on the concrete surface4 ,when completed the surface must conform closely to the pavement datum so that there will be no depressions or elevations exceeding one-fourth inch above or below the pavement datum4 ,,hydraulic ,,concrete ,,roadway ,,pavement#ei #aac4 ,the sub-foundation for hydraulic concrete pavement shall be prepared as specified in ,section #bf4 #aad4 ,the pavement shall be constructed in two courses called the bottom course and the top course1 as hereinafter specified4#fj #aae4 ,bottom ,course4--,the bottom course shall be four 7#d7 inches in thickness#fa and shall be composed of the materials specified in ,sects4 #bi1 #cj1 and #ca4 ,the concrete shall be composed of one part ,portland cement1 three parts sand and six parts of broken stone1 and shall be mixed and placed as specified in ,sects4 #ce and #cf1 but its top surface when properly compacted shall be parallel to and not less than two 7#b7 nor more than two and one-half 7#b7 inches below the pavement datum4 #aaf4 ,top or ,surface ,course4--,the top course shall be composed of the ,portland cement specified in ,sect4 #bi1 the sand specified in ,sect4 #cj except that it shall be especially clean1 and the grains shall be of such size that at least seventy-five per cent4 7#ge7 of the mass will fail to pass a screen having thirty 7#cj7 meshes to the linear inch1 and shall be of superior quality for making concrete2 and of crushed ,trap ,rock1#fb or of stone equally hard1 strong and durable4 ,the trap rock shall be crushed to such sizes that all will pass through a screen having meshes one and one-fourth 7#a7 inch square and that none will pass through a screen having meshes one-half 77 inch square1#fc and it shall be free from clay1 refuse or other foreign substances4 #aag4 ,the surface-course concrete shall be composed of one part ,portland cement complying with ,sect4 #bi1 one and three-quarters 7#a7 parts of sand1 and1 generally1 three and one-half 7#c7 parts of crushed stone1 but the ratio of crushed stone shall be such that in the completed concrete the volume of mortar in the compressed mass shall exceed by about fifteen per cent4 7#ae7 the voids in the stone4#fd ,the cement and sand shall be thoroughly mixed together dry1 enough clean water then added to make a rather wet mortar and the mixing continued until the materials are thoroughly incorporated into a homogeneous mass4 ,the crushed stone shall then be added1 and the mixing continued until every fragment of stone is completely covered with mortar4 ,sufficient water shall be added during the mixing1 if necessary1 to make a 8wet0 concrete1 but not so wet that free water will flow from the mixed mass4 ,in handling and adding the stone to the mortar care must be taken to prevent the stone segregating into masses of different sizes4 ,the concrete for the top course shall be made with special care and thorough work1 the intention being to secure a superior quality of concrete4#fe #aah4 ,the concrete thus prepared shall be placed upon the bottom course before the latter has begun to set#ff and carefully graded so that when properly compacted its top surface will coincide with the pavement datum4 ,the concrete will then be well rammed by rammers having a face of #f by #f inches and weighing not less than twenty 7#bj7 pounds after which the surface will be completed by rolling with a power roller of the asphalt type weighing not less than five 7#e7 tons4#fg ,all these operations must be completed before any of the concrete in either course shall have begun to set4 ,the surface shall not be plastered with neat mortar nor shall it be trowelled4 #aai4 ,the completed surface must coincide with the pavement datum to the extent that a properly formed template when applied to the surface shall show no departure from the pavement datum exceeding three-sixteenths 77 inch4 #abj4 ,after the laying of the pavement has been completed it shall be allowed to stand until the concrete of both courses shall be fully set1 which period shall be not less than ten 7#aj7 days1 or longer1 if conditions make a longer time necessary1 as the engineer may direct1 of which he shall be the sole judge4 ,during this period the concrete shall be kept in a moist condition throughout1 by sprinkling with hose or otherwise4 ,no travel shall be allowed upon the street until the engineer shall open it for public use4 ,the concrete shall not be laid during rain storms or when the thermometer is below forty-five 7#de7 degrees ,f41 and in case there may be danger from frost the whole surface of the concrete shall be covered by straw or hay4 ,manure must not be used for this purpose4 #aba4 ,expansion ,joints4#fh--;,an expansion joint along the curbing on each side of the street shall be provided in accordance with ,sect4 #aja4 ,expansion joints shall also be provided and constructed as follows3 ,wherever the width of the pavement exceeds twenty 7#bj7 feet between curbs there shall be a expansion joint along the longitudinal center of the street2 expansion joints shall also be made1 at right angles to the street and extending continuously from curb to curb1 at distances apart not exceeding twenty 7#bj7 feet4 ,these expansion joints in the body of the pavement shall be made by cutting entirely through both courses of concrete along a straight line1 using a special straight-edged cutter not more than three-sixteenths 77 inch thick1 when the concrete is laid in hot weather and not more than three-eighths 77 inch thick if the concrete is laid when the thermometer is below sixty 7#fj7 degrees ,f4 ,the cutting of the expansion joints shall be carefully and skillfully done1 and after each joint is cut a special ,t-shaped smoother1 the stem of which is one inch deep and of the same thickness as the cutter shall be worked back and forth in the joint until the edge of the concrete adjoining the joint shall be well and smoothly compacted4 ,the smoother shall be so formed as to round off the corners of the concrete to a circular form having a radius of one-fourth 77 inch4 ,all these operations shall be completed before the concrete has begun to set4 ,after the concrete has set and before the street is opened to travel all expansion joints shall be poured full of bituminous cement1 as specified in ,section #ij4fi #abb4 ,bituminous ,coating4#gj--;,after the concrete shall have become fully set as determined by the engineer and before the street is opened to travel the whole surface of the pavement shall be covered by a finishing coat of bituminous road oil as hereinafter specified4 ,the road oil shall be prepared from native asphalt or from a crude oil having an asphaltic base4 ,not less than #ie per cent4 of the oil shall be soluble in cold carbon di-sulphide1 and it shall contain not less than thirty 7#cj7 per cent4 of solid asphalt1 nor more than ten per cent4 of fixed carbon4 ,it shall be of such consistency as to flow freely at a temperature of seventy-five degrees 7#ge7 ,f4 ,the oil shall not be applied except when the road surface is perfectly dry and when the temperature of the air is not below #fj ,f4 ,the oil shall be evenly distributed over the whole surface of the street at the rate of one-half 77 gallon of oil per square yard of surface1 and well worked over the surface with squeegees or other suitable devices4 ,not less than twenty-four hours after the application of the oil the surface of the pavement shall be evenly covered to a depth of one-fourth inch with clean1 dry stone screenings or coarse sand1 after which the street may be opened to travel4 ,,general ,,specifications ,,for ,,experimental ,,or ,,untried ,,pavements#ga #abc4 ,contractors or promoters submitting proposals for the construction of new1 experimental1 or special street pavements1 the merits of which have not been established by experience in the city of 4441 must submit with their proposal a full and complete set of specifications for the construction of the pavement4 ,if contract shall be awarded under said proposal1 said specifications will be made a part of the contract entered into4 ,the ,engineer will enforce compliance with these specifications1 as the construction work proceeds1 without assuming or incurring any responsibility for the character1 quality1 serviceability or durability of the resulting pavement4 ,but the ,contractor shall be subject to and shall comply with the requirements and stipulations of ,sects4 #a to #be1 inclusive1 of these specifications4 #abd4 ,special ,guaranty4#gb--;,inasmuch as the pavement to be constructed under the special specifications submitted by the ,contractor is more or less of an experimental character1 having not been heretofore used in the city of 444 to an extent sufficient to establish its value1 the ,contractor shall be held wholly responsible for the utility1 serviceability and durability of the pavement so constructed2 and he shall enter into a guaranty to the effect as follows3 ,that the pavement will fulfill all the usual and legitimate requirements of a satisfactory roadway pavement upon the street upon which it is to be laid4 ,that the pavement will successfully serve and endure the travel to which the street may be subjected for a period of 444 years next following the date of the certificate of its completion and acceptance1 and shall be in good condition at the end of that period1 ordinary and reasonable wear and tear1 and accidental or other injuries not due to defects in the pavement itself1 excepted4 ,that the ,contractor will1 at his own cost1 keep the said pavement in satisfactory repair during said period of 444 years1 and will leave it in a condition of satisfactory repair at the end of that period4 ,that the ,engineer1 or his successor or successors in office1 shall be the sole and final judge as to whether the conditions of this guaranty shall be1 or shall have been complied with4 ,that in case the pavement shall not1 in the judgment of the ,engineer1 fulfill the terms and conditions of this guaranty at any time during said period of 444 years1 or upon its expiration2 or in case the ,contractor shall fail to make all or any of the repairs that may in the judgment of the ,engineer be or become necessary during said period of 444 years1 within a reasonable period to be determined by the ,engineer1 but not to be less than twenty 7#bj7 days after notice to make such repairs has been given him by the ,engineer1 he 7the ,engineer7 may proceed to make or to have made such repairs1 or to repave the street1 in any manner that he may deem necessary or advisable1 and to charge the cost of such repairs or repavement to the ,contractor1 provided1 that the sum or sums so charged against the ,contractor shall not1 in the aggregate1 be more than the amount paid to the ,contractor for the construction of the pavement4 #abe4 ,bond4--,the ,contractor shall give bond with sureties satisfactory to the ,engineer in a sum not less than the estimated cost of the pavement at the contract prices1 the term of the bond to extend over the entire period of 444 years1 for which the pavement is guaranteed4 #abf4 ,during the said period of 444 years the ,contractor shall1 upon being notified by the ,engineer so to do1 make any repairs to the pavement that may become necessary by reason of cutting into it for the purpose of constructing or repairing pipes1 conduits or other underground structures1 or street railroad tracks1 or by reason of accidental or unusual causes1 or of any causes other than those due1 in the opinion of the ,engineer1 to the failure of the pavement to meet and fulfill the terms of the guaranty stipulated in ,section #abd4 ,and for making such repairs the ,contractor shall be paid the price of 444 per square yard for the repairs actually so made4 ,repairs so made shall be subject to the terms of the guaranty1 stipulated in ,section #abd1 until the expiration of the said term of 444 years after the date of the original certificate of completion and acceptance4 ,in case the ,contractor shall neglect or fail to make such repairs within a period of twenty 7#bj7 days after he shall have received notice to do so1 the ,engineer may proceed to make or to have made such repairs1 and he shall charge to and collect from the ,contractor the cost of the repairs so made4 ,,hydraulic ,,concrete ,,combined ,,curb ,,and ,,gutter#gc #abg4 ,hydraulic concrete combined curb and gutter shall be constructed in accordance with general plan ,no4 444 attached to and made a part of these specifications1 but the rise from the gutter to the top of the curb may be varied so as to facilitate drainage4#gd #abh4 ,excavation4--,all excavation required for the curb and gutter shall be completed and trimmed to the proper lines as shown by the drawing4 ,the drainage trench under the curb and gutter shown on the drawing shall have the top width and general form shown in the drawing but its depth may be varied to secure proper drainage1 as the engineer may direct1 provided that its depth below the base of the concrete shall not be less than nine inches nor more than two feet4 #abi4 ,broken ,stone ,drainage4#ge--;,after the excavation shall have been completed the trench shall be filled up to the level of the base of the concrete with sound1 durable broken stone1 or coarse gravel1 from which the small fragments shall have been removed by screening over a wire screen having openings not less than one inch square4 ,the stone or gravel shall be thoroughly tamped in the trench in layers not more than six 7#f7 inches thick by the use of rammers weighing not less than thirty 7#cj7 pounds and having a face area not exceeding thirty-six 7#cf7 square inches1 and its completed top surface shall conform truly to the designed base of the concrete4 ,these drains shall be connected at suitable intervals with sewers1 drains or other outlets to keep them free from standing water4 ,the trench filling shall be completed at least twenty-five feet in advance of placing the forms for the concrete4 #acj4 ,concrete4#gf--,the concrete shall be made of one 7#a7 part ,portland cement1 one and three-fourths 7#a7 parts of sand and three 7#c7 parts of crushed stone or clean gravel4 ,the ,portland cement shall comply in all respects with the requirements of ,section #bi of these specifications4 ,the sand shall be clean1 sharp silicious sand made up of grains of such size that not more than fifteen per cent4 7#ae7 will pass a number thirty 7#cj7 sieve4 ,it shall not contain more than five per cent4 7#e7 of clay or loam nor more than two per cent4 7#b7 of organic matter or other refuse4 ,the stone shall be sound1 hard1 durable1 and freshly broken1 free from clay1 loam1 organic matter1 or other impurities4 ,trap rock or granite will be preferred1 but limestone1 if hard and sound1 may be used with the approval of the engineer4 ,only those fragments of the crushed stone that pass a screen with openings three-fourths inch square and those that are held on a screen with openings one-fourth inch square shall be used in the concrete4 #aca4 ,mixing and ,placing ,concrete4--,the concrete shall be mixed in accordance with ,section #ce of these specifications4 ,very thorough mixing will be required4 ,the mixed concrete shall be handled so as to prevent as far as practicable any separation or segregation of the stone and mortar4 ,when in place it shall be compacted by tamping and where placed against forms1 forking or other effective means must be used to bring mortar to the surface and to secure complete contact between mortar and forms1 so as to leave a solid1 homogeneous and unbroken surface when the forms are removed4 ,where the concrete may not be laid against forms1 all exposed surfaces must be troweled to a true surface conforming accurately to the lines shown by the plans1 templates and straight-edges being used where necessary4 #acb4 ,weather4--,concrete in combined curb and gutter shall not be laid in freezing weather nor shall frozen materials be used in the work4 ,completed work must be securely protected from frost for at least seven days after it is laid4 ,any concrete curb and gutter that may become frozen within that period shall be wholly removed and replaced with new work4 #acc4 ,expansion ,joints4--,the combined curb and gutter shall be divided into blocks or panels not more than twelve feet long1 by clear1 open expansion joints perpendicular to the face of the curb1 extending entirely and continuously through the whole mass of the concrete4 ,these expansion joints shall be three-eighths inches wide and may be formed either by cutting through the completed curb and gutter with a suitable tool1 or by the use of iron forms or partitions1 but in either case the corners at the ends of the blocks must be made solid and dense and troweled with a suitable tool4 #acd4 ,circular ,corners4--,at the intersections of streets1 circular corners1 having a radius equal1 generally1 to one-fifth of the width of the roadway of the narrower street1 shall be constructed of the same dimensions and quality as on the body of the street1 and the curb and gutter will be extended along the line of the cross street back to the front lot-lines4 ,properly curved circular curb and gutter shall also be constructed at all angles exceeding five degrees in the line of the curbing4 #ace4 ,corner ,protection4--,galvanized steel corner protectors or nose-pieces shall be used to protect the upper and outer corner of the curb at all circular corners and angles in the street4 ,this steel protection may be of any pattern or section procurable in the market and approved by the engineer4 ,it shall be firmly anchored and secured into the concrete4 #acf4 ,finishing4--,after the forms have been removed and before the concrete has set up too hard to be affected by the brush1 the face and top of the curb shall be lightly scrubbed by a suitable wire brush so as to completely remove any glazed surface and to produce a surface of uniform texture and appearance4 ,dry cement or neat cement mortar shall not be used for dressing up exposed surfaces4#gg #acg4 ,forms4--,the forms used may be of dressed lumber or of metal as the contractor may prefer4 ,but they shall have sufficient strength and rigidity to hold the concrete firmly in place1 and to preserve the correct dimensions1 alignment and levels of the curb and gutter4 #ach4 ,protection4--,the completed curb and gutter shall be protected from fracture1 deformation or spalling until the concrete has fully set4 ,the concrete must be kept moist for at least five days after it has been laid4 ,any part of the curb and gutter that shall have become injured before it is accepted or the street is opened for travel shall be taken up and replaced by the contractor4 #aci4 ,payment4--,concrete combined curb and gutter will be paid for by the linear foot in place1 the measurement to be made along the upper and outer corner of the curb4 ,the price per linear foot named in the contract will cover all the excavation or grading required and all the materials and labor1 including all necessary forms1 for constructing the curb and gutter complete4 ,but the crushed stone used for drainage will be paid for by the cubic yard measured in place1 and steel corner protection will be paid for by the linear foot in place1 at the prices named in the contract4 ,,hydraulic ,,concrete ,,sidewalks ,note4--,these specifications conform to the common practice of laying the sidewalk in two courses4 ,in the author's judgment this is neither necessary nor desirable4 ,he believes that it would be better and somewhat cheaper to use a single course of concrete four inches in thickness4 ,he suggests for this concrete the ratios of one cement1 two sand1 and three and one-half stone1 the latter to be crushed to pass a screen with five-eighths inch square openings4 ,tamping will bring a sufficient quantity of mortar to the surface to permit of satisfactory finishing4 ,while the materials for such a single course of four inch concrete would cost somewhat more1 the saving in cost of labor would1 at usual prices of material and labor1 make the single-course construction somewhat cheaper1 while the solid four inches of richer concrete would make the walk much stronger4 ,in fact1 a single course of such concrete three inches thick would be sufficient in a great majority of cases4 ,while the surface might not have the glazed appearance common in the two-course work it would be really better for use--a polished and slippery surface on sidewalks is not desirable4 ,,specifications#gh #adj4 ,the hydraulic concrete sidewalk shall be 444 feet in width and its outer edge shall be 444 feet from the outer face of the street curbing4 ,it shall be constructed with two courses of ,portland cement concrete as hereinafter specified4 #ada4 ,excavation and ,grading4--,the ground to be occupied by the sidewalk shall be excavated or filled to a sub-grade which after being compacted shall be 444 inches#gi below the finished surface of the sidewalk4 ,the sub-grade shall be neatly dressed to a plane surface sloping downward toward the street one-fourth inch in one foot horizontal1 and to such longitudinal gradients as the engineer may prescribe4 ,the completed sub-grade shall project four 7#d7 inches in excavation and eighteen 7#ah7 inches in embankment on each side beyond the edges of the completed sidewalk4 ,after the grading is completed the surface shall be compacted by rolling or ramming4 #adb4 ,drainage ,course4--,upon the sub-grade prepared as specified in ,section #ada a drainage course composed of broken stone1 gravel or boiler-plant cinders1 444 inches#hj in thickness shall be laid4 ,broken stone for this purpose may be of any durable stone crushed to such size that all will pass through a screen with two inch openings4 ,crusher-run material may be used unless it contains an excessive quantity of fine material4 ,gravel for the purpose may be any sound durable gravel all of which will pass through a two inch screen and be retained upon a one-fourth 77 inch screen4 ,if cinders are used they must be good boiler-plant cinders from which the ashes have been screened out4 ,the cinders must be thoroughly drenched with water at least one week before they are placed in the sidewalk4#ha #adc4 ,this drainage material shall be placed on the sub-grade and properly graded4 ,after grading it shall be thoroughly compacted by ramming or rolling1 and its surface shall be brought to a plane parallel to and 444 inches below the designed surface of the sidewalk1 after which the surface inequalities may be leveled up with screenings or small gravel4 ,the bottom of the drainage course shall be connected with the street drains or sewer inlets by three-inch hard drain pipe at such points1 not more than three hundred feet apart1 as will drain all standing water out of the drainage course4 #add4 ,concrete1 ,bottom ,course4--,the bottom course of concrete 444#hb inches in depth1 shall be constructed and placed in accordance with ,sections #bh1 #bi1 #cj1 #ca1 #cb1 #cc1 #cd1 #ce and #cf of these general specifications1 except that the maximum size of the crushed stone shall not exceed one-half the thickness of the bottom course of concrete and the concrete shall be uniformly composed of one part ,portland cement1 three parts sand and six parts of crushed stone4 ,its upper surface shall be brought to a plane parallel to and one inch below the designed sidewalk surface4 #ade4 ,surface or ,finishing ,course4--,the surface or finishing course shall be of concrete1 one inch thick1 composed of one part ,portland cement1 one and one-half parts sand and two and one-half parts of hard1 durable stone1 crushed to such sizes that all will pass through a screen having openings one-half 77 inch square and none will pass through a screen having openings one-eighth 77 inch square4#hc ,this concrete shall be made as specified in ,sections #bh1 #bi1 #cj1 #ca1 #cb1 #cc1 #cd1 #ce and #cf except in the particulars named in the preceding paragraph4 ,care must be taken to make the mixing very thorough4 ,the quantity of water used in this concrete shall be just sufficient to make a moderately wet mixture1 and care shall be taken to make the different batches as nearly as practicable of the same consistency4 ,the surface concrete shall be spread over the bottom-course concrete before the latter has begun to set1#hd properly graded1 well compacted by ramming1 and its upper surface brought to the true designed plane and surface of the sidewalk by the use of straight-edges and troweling1#he after which the surface shall be lightly gone over with a wire broom or brush to slightly roughen the surface4 ,the finished plane of the sidewalk shall have a transverse downward slope toward the street of one-fourth 77 inch to one foot of horizontal width4 ,at no place shall the thickness of the surface-course be less than three-fourths of one inch4 ,the outer top corners of the sidewalk shall be rounded off with a suitable tool to a radius of three-fourths 77 inch4 #adf4 ,forms4--,substantial and suitable forms of wood or iron shall be furnished and used by the contractor to support the concrete until it is hard set1 when they shall be removed at his expense4 #adg4 ,expansion ,joints4--,after the laying of both courses of concrete is completed expansion joints at right angles to the sidewalk1 and not more than four 7#d7 feet apart shall be constructed in the sidewalk in the following manner3 the joint will be located by a line on the surface of the sidewalk and a straight-edged cutting tool one-fourth 77 inch thick will be used to cut entirely through both courses of concrete1 accurately along the line marked out1 entirely across the sidewalk1 after which a ,t-shaped trowel or tool shall be used to smooth and compact the cut surfaces for a depth of one inch1 and to round off the corners of the sidewalk blocks to a radius of one-fourth 77 inch4#hf ,where the ends of the sidewalk abut against the curbing a clear expansion joint one and one-fourth 7#a7 inches wide shall be left between the sidewalk and the curb4 #adh4 ,after the concrete laying is completed it shall be protected from use or injury until the concrete is set hard enough to withstand travel1 and it shall be kept continuously damp for at least five days after the concrete is laid4 #adi4 ,weather4--,concrete in sidewalks shall not be laid in freezing weather nor shall frozen materials be used in the work4 ,completed work must be securely protected from frost for at least seven days after the concrete is laid4 ,any concrete sidewalk that shall become frozen within that period of time shall be wholly taken up and replaced with new work1 at the expense of the contractor4 #aej4 ,regrading4--,directly after the concrete is completed1 the forms removed1 and the work inspected by the engineer1 the space between the outer edge of the sidewalk and the street curb shall be excavated or filled up and dressed to a plane one inch below the top of the sidewalk and the top of the street curb2 and the space on the inner side of the sidewalk shall be graded to a plane one inch below and parallel to the surface of the sidewalk for a distance of two feet back from the edge of the sidewalk and completed with a slope of one and one-half to one to the natural surface of the ground4 ,where this regrading requires filling up the filling material1 for a depth of four inches from the surface1 shall be good1 rich surface soil4 #aea4 ,should any defects due to faulty material or workmanship develop in the sidewalk within one year after the completion of the same the contractor shall repair or reconstruct all such defective places at his expense1 doing the work in accordance with these specifications4 #aeb4 ,measurement and ,payment4--,concrete sidewalk will be measured and paid for by the square foot of completed sidewalk surface1 and the unit price per square foot shall cover the entire cost of the work1 including grading1 drainage work1 all material and labor1 forms1 and the regrading or dressing up after the completion of the concrete work2 except that the drain pipe used will be paid for per linear foot at the price named in the contract which price shall cover the cost of furnishing and putting the pipe in place complete4 ,,part ,,ii ,,instructions ,,to ,,inspectors ,,on ,,street ,,paving ,,work ,,introductory ,,note ,any general code of instructions for inspectors on street paving work must necessarily be little more than tentative or suggestive1 as applied to any one city4 ,that here presented is intended for use in connection with the specifications in ,part ,i of this book4 ,different specifications might make necessary many changes in the instructions that follow4 ,the local or special conditions in any city might also make them inapplicable without material modifications and additions4 ,the author believes that in every city where considerable street pavement work is prosecuted and a number of inspectors employed on such work1 some such code of instructions to inspectors should be formulated and used4 ,even where the inspectors are of high character and fully competent1 the adoption of a system of rules and regulations relating to their work will tend to unify procedure1 prevent misunderstandings and promote good discipline4 ,the preparation of such a code of instructions requires no little time and thought1 especially where there are no precedents to suggest what is needed1 or to be used as rough patterns4 ,it is with the hope that the code here presented may be found useful in this way1 even though it may be not appropriate for adoption in any given city1 that it is offered to municipal engineers4 ,,general ,,remarks ,,about ,,inspection ,,and ,,inspectors ,the necessity of having competent and honest inspectors upon any public work during its construction need not be here argued4 ,it is generally understood and recognized in the case of work carried out by contract4 ,where the contractor is incompetent1 careless or unreliable1 inspection is absolutely necessary if good work is to be secured4 ,even where the contractor thoroughly understands his business and intends to faithfully comply with the specifications and to do all his work in a proper manner1 the inspector cannot safely be dispensed with4 ,the contractor cannot at all times be on the work2 whatever may be his intention and instructions1 foremen and laborers cannot be depended upon to exercise the proper care and judgment1 even where they have no inclination1 motive or interest to do otherwise1 which is not always the case4 ,it seems to be deeply and almost irradicably fixed in the mind of the average foreman on municipal work that he is expected to show his ability and skill by evading or circumventing the strict requirements of the specifications and the watchfulness of the municipal agents1 whatever his employer may say to the contrary4 ,even when fairly careful1 honest and conscientious he may need friendly oversight4 ,he is naturally and properly anxious to save all the money he can for his employer1 whether from a desire to loyally serve that employer's interest1 or to enhance his reputation for doing work cheaply4 ,he may not appreciate the importance of minor requirements of the specifications and may believe they can be ignored without real detriment to the utility of the completed work4 ,like other men he may sometimes be careless or forgetful1 however good his intentions4 ,these human qualities are not confined to foremen on contract work4 ,they are liable if not likely to be found in the foremen on work done for the municipality by the direct1 or day's work system4 ,they may be encouraged by the impression or belief that they will not be held by the municipal authorities to as strict an observance or accountability as they would be if the work were being done by a contractor--which is too often true4 ,the absence of some of the motives of foremen employed by contractors is1 therefore1 not a sufficient reason for dispensing with inspectors on work done by the city direct4 ,it should be trite to say that inspectors should be chosen with some regard to their qualifications for the work they are expected to do4 ,one cannot1 of course1 expect to secure experts for such positions at the rate of compensation usually paid2 but it is reasonable to require that an appointee to such positions shall possess the following qualifications3 ,that he shall be honest1 trustworthy and loyal4 ,that he shall be a man of at least average intelligence and common sense4 ,that he shall have some practical knowledge of or experience in the work he is employed to inspect4 ,that he shall be a man of good personal habits4 ,that he shall be habitually punctual1 industrious1 and alert1 and shall possess a fair share of that quality commonly called 8backbone40 ,it will not1 ,i am sure1 be denied that a very large number of the inspectors found upon municipal public work fall short in one or more of these qualifications4 ,inspectors who habitually expect or accept compensation or gratuities from the contractor violate the first requirement1 and their number is astonishingly large4 ,these are useless1 or worse than useless1 to the municipality4 ,there are not a few contractors who will take advantage of the presence on the work of such inspectors to do things that they would not do if thrown wholly on their own honor and responsibility4 ,contractors can hardly be blamed for expecting some compensation for the money thus exacted or accepted by the inspector from them4 ,the requirement that the appointee shall have some practical knowledge of and experience in the work he is expected to do1 while often disregarded1 is of real importance4 ,good workmanship embraces many small details that are essential1 and inferable from the specifications1 but cannot be stated at length therein1 and the inspector should have a good working knowledge of these4 ,unfortunately1 large numbers of inspectors are employed for personal or political reasons1 or because more competent men are not available4 ,they know little or nothing from practical knowledge and experience about the work they are assigned to inspect4 ,efficient service cannot be expected from such1 even if they possess the other necessary qualifications4 ,the obvious remedy1 where a sufficient number of qualified inspectors cannot be obtained at call1 would be to train up a permanent force by having the promising tyros serve a sufficient apprenticeship under older and more experienced inspectors2 but this is seldom done4 ,inspectors1 whether appointed by the engineer in charge or not1 should be absolutely under his control1 including the power of dismissal without unnecessary formalities4 ,where they are under civil service regulations and can be dismissed only upon charges and after a hearing before some third person1 the obstacles in the way of promptly getting rid of an incompetent or unfaithful inspector are often so great as to be discouraging if not deterrent4 ,he may be clearly below a reasonable standard of honesty or efficiency but it may be very difficult to formulate distinct charges and support them with positive evidence4 ,thus1 one may be morally certain that an inspector is accepting gratuities from a contractor1 but unable to prove it by legal evidence4 ,if in such cases the judgment and integrity of the responsible engineer cannot be trusted1 he is not fit1 himself1 for the position he occupies4 ,the question of how much authority and power shall be given to the inspector is always a troublesome one4 ,if he be too much limited or restricted1 he cannot properly discharge his duties or command the necessary respect from the contractor and his employees2 if he be given too much authority and is disposed to be arbitrary or unreasonable1 the contractor may be unjustly treated4 ,so far as the definite requirements of the specifications are concerned there can usually be no room for going astray1 but in the numberless little details not specifically covered in the specifications1 or where their language and intent is not clear1 differences and disputes may result which require a degree of knowledge and judgment that the inspector may not possess1 and where his decisions might be against the interests of the municipality or unjust to the contractor4 ,in such cases the matter should always be referred to the engineer or his assistant4 ,where inspectors are employed upon work done directly by the municipality the relation between them and the superintendent or foreman should be clearly defined and understood4 ,briefly stated1 this relation should be the same as that between the inspector and the contractor on contract work4 ,,instructions ,,for ,,the ,,guidance ,,of ,,inspectors ,,on ,,street ,,paving ,,and ,,incidental ,,work ,,general #a4 ,the chief duty of the inspector is to see that the work to which he is assigned shall be carried out in full and strict accordance with the plans and specifications therefor1 and with such additional instructions as may from time to time be given by the engineer4 #b4 ,these instructions are intended to supplement but in no case to take the place of the specifications for the work1 which must be fully and strictly complied with1 unless they are changed or modified by the engineer4 #c4 ,wherever the words 8the engineer0 are used in these instructions they refer to the chief engineer in charge of the work for the municipality1 or his authorized deputies or agents4 ,wherever the words 8the contractor0 are used they refer to the person1 or firm1 or corporation under contract to perform the work to which you are assigned1 or his agents or employees engaged upon the work4 #d4 ,you will report to and be under the exclusive direction and control of the engineer4 #e4 ,upon being assigned to any work you will obtain copies of the plans and specifications under which it is to be done1 and will carefully read and acquaint yourself with all their provisions and requirements4 ,if any part of these plans and specifications are not clearly understood by you1 you will ask the engineer for explanations and instructions1 and will be governed thereby4 ,failure to understand or to be familiar with the plans and specifications will in no case be accepted as an excuse for not complying with and enforcing them4 ,you will also obtain1 study and familiarize yourself with all the blank forms1 reports1 etc41 that are to be used by you on the work1 so that they may be correctly utilized2 you will also obtain a proper supply of such apparatus1 tools1 stationery1 etc41 as you will need upon the work4 #f4 ,in inspecting any work done under contract you are to assume that the contractor is bound to carry out in good faith the plans and specifications attached to his contract1 and that he may be1 and must be1 held to a strict compliance with them unless you receive instructions to the contrary from the engineer4 ,you will be held responsible for the enforcement of these plans and specifications so far as they relate to the doing of the work4 #g4 ,in case the contractor or his agents shall neglect or refuse to comply with the plans and specifications or to perform the work in a proper manner1 or in accordance with the instructions of the engineer1 you will direct him to suspend the particular work in fault and will report all the facts promptly to the engineer and await his instructions1 which1 when received1 you will proceed to enforce4 #h4 ,you will be expected to be upon the work at all times when work is in progress1 whether during ordinary working or office hours1 or not4 ,but in case the contractor shall work continuous day and night forces1 or otherwise so conduct the work as to require the presence of an inspector for unusual or unreasonable hours of service1 you will notify the engineer and ask instructions or assistance4 ,if for any reason you are to be unable to be present whenever work is in progress you will promptly notify the engineer in time to enable him to supply a substitute4 #i4 ,all reports and records required of you by the engineer must be promptly made up and forwarded to him at the time and in the manner he may direct4 ,you will promptly acknowledge in person or writing any instructions received from the engineer and in case such instructions are not clearly understood by you1 you will ask for explanation or advice4 ,you will keep a notebook or diary in which all occurrences or matters of interest relating to the work will be recorded each day1 which book will be delivered to the engineer on the completion of the work1 or whenever your connection therewith may end4 ,all diaries1 notebooks and records kept on the work are the property of the city4 #aj4 ,while your first duty is to see that the work is done in accordance with the plans and specifications1 you will1 so far as consistent with this duty1 be considerate of the interests of the contractor and facilitate his work as much as practicable4 ,materials should be inspected promptly upon delivery and in such a manner as not to delay or discommode the contractor more than is necessary4 ,errors1 defects or delinquencies in the work should be detected and called attention to promptly1 so as to avoid tearing up and re-construction as far as practicable4 #aa4 ,orders and instructions should be given to the contractor or his foremen or representatives on the work and not to the laborers1 unless in urgent cases4 #ab4 ,you shall not at any time1 before1 during1 or after the completion of the work1 ask or accept from the contractor or any of his agents or employees1 or from any other person whom you may have reason to believe is acting for the contractor1 any money1 gifts1 gratuities or other considerations of value1 whether as compensation for services rendered him or otherwise4 ,the penalty for violation of this rule will be dismissal from the service followed by such legal prosecution as the engineer may direct4 ,this rule does not apply to the ordinary small courtesies common between gentlemen associated in business4 #ac4 ,it is a condition of your employment that your services shall be loyal to the interests of the municipality1 efficient1 and satisfactory to the engineer1 and that whenever in his opinion your service falls short of this standard he may dismiss you at any time1 without previous notice4 ,,street ,,paving ,,work #ad4 ,sub-foundation4--,the usual procedure in preparing the sub-foundation for a pavement is3 ,the removal of the old pavement if one exists on the street4 ,the setting of new or the resetting of the old curbing4 7,if concrete combined curb and gutter is used it is not constructed until after the rough grading is done47 ,the rough grading of the street4 ,the fine grading of the street4 ,in this work the main things for the inspector to look after are the following3 ,if an old pavement is to be taken up and any part of it is to be reserved for use by the city1 see that the material is not injured in handling and is disposed of as the specifications or the instructions of the engineer require4 #ae4 ,curbing4--,new curb stone should be inspected as soon as practicable after it is delivered on the street so that the contractor may have time to replace any that may be rejected4 ,rejected stones should be plainly marked on their tops with red paint1 and the contractor required to remove them from the street4 ,stones that are defective in dressing should be given some distinctive mark and the attention of the contractor called to them so that the necessary redressing may be done well in advance of the setting1 and reinspected4 ,if the old curb stone is to be redressed and reset1 it should be inspected as soon as possible after it is taken out and all stones that are not suitable for re-use rejected and removed from the work4 ,the redressing of the stones should be looked after carefully4 ,the tendency in this work is toward the use of old stones that do not1 or cannot be made to comply with the specifications1 and toward laxity in the dressing4 ,setting ,curbing4--,in the setting of curbing the points to be looked after are3 ,to see that the trenches are excavated to the full dimensions so as to provide space for the use of the full quantity required of concrete1 gravel or broken stone in which the curb is to be embedded4 ,to see that the stones are set to true grade and alignment4 ,that the concrete1 gravel or crushed stone used is of the proper quality1 the proper quantity used1 and that it is placed and compacted so as to fill the spaces designated under and around the stone4 ,the tendency of the workmen is to treat these details as unimportant and to slight the work4 ,after the curbing is set any spaces between it and the edge of the sidewalk are to be cleaned out1 filled and trimmed with ,portland cement mortar4 #af4 ,rough ,grading4--,if plows and scrapers are used in the rough grading1 see that they are not allowed to penetrate or to disturb the natural soil below the true grade1 and to prevent this it is better to require that the plowing and scraping shall not approach nearer than one or two inches to the true grade4 ,if embankment or filling is necessary1 the filling material must be deposited in regular layers not more than six inches deep and each layer must be well compacted by rolling or ramming before the next layer is applied4 #ag4 ,fine ,grading4--,the fine grading 7with pick or mattock and shovel71 to bring the sub-grade to the true grade and contour required1 should be done with reasonable accuracy and care4 ,allowance must be made for compression under the roller1 so that when completed the surface shall not vary more than half an inch below nor more than a quarter of an inch above the true grade1 in order that room for the full thickness of concrete foundation may be provided1 and no more4 ,humps1 depressions and irregularities of the surface are to be avoided4 ,the fine grading will be completed by thoroughly rolling or tamping the surface to make the soil firm and dense4 ,on some soft or wet1 clayey soils1 excessive rolling may produce a plastic or 8liver-like0 condition and the rolling should be discontinued where such a tendency appears4 #ah4 ,work ,incidental to ,grading4--,where it is a part of the contractor's work to reconstruct or readjust catch basins1 manholes1 covers1 and other structures1 he should be required to keep this work done well in advance of the laying of the concrete foundation4 ,if this work is delayed until after the main body of the concrete is in place1 leaving openings to be filled later1 hurriedly and perhaps carelessly1 it may result in weak patches in the concrete around these structures1 where1 in fact1 the concrete should be strongest4 ,,concrete ,,foundations #ai4 ,the concrete foundation of a pavement is a most important part of the work1 and must not be slighted in any way4 #bj4 ,quality of ,materials4--,the quality of the materials used for making the concrete are fully described in the specifications1 and they must be substantially and uniformly adhered to4 ,the ,portland cement delivered on the street will presumably have been previously inspected and accepted by the engineer1 but any change in the kind1 or brand1 or apparent quality of the cement delivered after the beginning of the work should not be permitted without the approval of the engineer4 ,barrels or bags of cement not plainly marked with the brand1 or name of the manufacturer must be rejected4 ,you will frequently make balls of stiff mortar from the cement and sand used 7#a part cement1 #b parts sand7 and set them aside for observation4 ,if in eight hours these balls do not set up hard the fact should be promptly reported to the engineer4 ,the sand and stone will naturally vary slightly from time to time1 but should not differ materially from the requirements of the specifications or the standards adopted by the engineer4 ,stone or gravel that contains any considerable quantity1 say more than #e1 of foreign matter1 such as soil or refuse1 should be rejected4 ,stone containing an excessive quantity of fine fragments or screenings bunched together in the pile1 should be mixed with the mass of larger stone before it is used1 so as to produce a mass of fairly even composition4 ,stone that is coated with mud1 or that is not sound and hard should be thrown out4 ,sand that is moderately coarse and does not contain more than #g of clay or soil1 and is free from vegetable refuse1 may be used4 #ba4 ,storing ,materials4--,cement stored on the street must be stacked up on dry lumber floors at least four inches from the ground and effectually covered to protect it from rain or snow4 ,packages of cement which1 when turned out for use contain hard lumps should be rejected4 ,sand and stone must be stored on tight lumber floors to prevent their admixture1 when being shoveled up1 with street soil or other impurities4 ,this requirement must be enforced4 #bb4 ,proportioning ,concrete4--,the proportions of cement1 sand and stone or gravel named in the specifications must be strictly adhered to4 ,a barrel of ,portland cement will be considered as four cubic feet and a standard bag of cement as one cubic foot4 ,it is usual for the contractor to measure the sand and stone by wheelbarrow loads4 ,in that case you will measure and determine the capacity1 in cubic feet1 of the convenient or average wheelbarrow load1 and determine the size and number of loads each of sand and stone required for one batch of concrete 7if made by hand7 and thereafter see that the quantities thus determined are used1 and the wheelbarrow loading uniform4 ,to measure the contents of a wheelbarrow load1 use a square box holding one cubic foot4 ,it cannot be accurately measured on the barrow4 ,as a check upon the proportioning of materials1 you should occasionally keep a record of the quantities of cement1 sand and stone used for1 say1 one or two hours1 and mark and measure up the quantity of concrete made with them1 and from this data compute the ratios of the materials used4 7,in ordinary street concrete1 proportioned #a3c3f1 the volume of rammed concrete made will just about equal the volume of the stone used47 ,where the concrete is mixed by a machine with automatic feeding devices1 reliance must not be placed upon the machine for proper proportioning4 ,frequent tests of the materials used and the volume of concrete turned out should be made as described above1 and any necessary corrections made in the feeding devices of the machine4 ,this test should be made daily if practicable4 ,the eye will usually detect any material change in the composition of the concrete1 and whenever such changes are observed the composition ought to be at once checked up by measurement4 #bc4 ,mixing ,concrete4--,see that the specifications are followed4 ,use sufficient water to make what is commonly called a wet concrete but not so wet that free water will drain from the mixed batch before ramming4 ,the test for proper mixing will be that all the fragments of stone are completely covered with mortar4 #bd4 ,placing ,concrete on ,street4--,all concrete must be placed and rammed before it begins to stiffen or set4 ,concrete should be so handled that the mortar will segregate or separate from the stone as little as possible4 ,when in place on the street it should make a mass of uniform consistency and appearance4 ,the concrete should1 as soon as placed on the street1 be graded to a proper thickness and surface1 and then well compacted by ramming4 ,insist on good ramming2 this part of the work is not often properly done4 ,the surface of the concrete should be brought to the true grade by proper grading and tamping4 ,where necessary to raise the surface1 additional concrete1 made of small stone1 may be applied during the tamping4 ,neat mortar should not be used for this purpose4 ,sweeping mortar over the surface with street brooms should not be permitted--it is useful only to cover up defects and to produce an extra smooth surface 7which is not usually desirable74 ,to measure the thickness of the bed of concrete1 lay a straight-edge upon the surface with the end of the straight-edge projecting a foot or two beyond the edge of the concrete1 and measure the space from the lower edge of the straight-edge down to the sub-foundation4 ,care must be taken to finish the surface of the completed concrete at the proper distance below and truly parallel to the grade and contour of the finished pavement4 ,this is more important in the case of sheet asphalt pavements1 since irregularities in the concrete will cause variation in the thickness of the finished asphalt surface1 which will affect the durability of the pavement4 ,the grade stakes for the concrete should therefore be carefully set and worked to1 and humps or depressions between the stakes should be avoided4 #be4 ,in hot1 dry1 weather the concrete must be kept damp by watering it until it is at least five days old1 and horse-travel over it must be prohibited until it has set up hard enough not to be injured thereby4 #bf4 ,old ,paving ,stone ,foundations4--,if a foundation is to be made of old paving stone blocks reset1 the important points to be looked after are1 ,the preparation of the sub-foundation4 ,the sand bed4 ,the setting of the blocks4 ,the grouting of the blocks4 ,the sub-foundation should be prepared1 where necessary1 as stipulated in ,sects4 #af and #ag of these instructions4 ,this part of the work is likely to be carelessly done unless proper work is insisted upon4 ,the sand used as a cushion course must be of good quality and reasonably clean4 ,the use of mixed sand and soil taken from the street excavation should not be permitted4 ,the blocks1 after being cleaned from adhering dirt1 should be set with reasonable care1 well bedded in the sand cushion1 and laid at such an elevation below the completed pavement surface1 that after being well rammed1 the surface will be at the proper elevation below the pavement datum4 ,the grouting of the joints is the most important part of the work4 ,see that the mortar is made and used in accordance with the specifications1 and that the joints are completely filled4 #bg4 ,broken ,stone ,foundations4--,the specifications for broken stone foundations are sufficiently explicit1 and compliance should be insisted upon4 ,thorough rolling is especially important4 ,,sheet ,,asphalt ,,pavements #bh4 ,the manufacture of the mixture for sheet asphalt pavement1 and the laying of it on the street1 involve a number of separate elements or operations4 ,the quality and durability of the pavement will depend largely upon the skill1 intelligence and accuracy with which each and all parts of the work are carried out4 ,the inspector1 both at the mixing plant and on the street1 must give constant and intelligent attention to the work4 #bi4 ,inspecting at ,paving ,plant4--,inspectors at the plant where the asphalt paving mixture is made will be provided with the following apparatus3 #a nest of standard sieves1 ,nos4 #aj1 #cj1 #ej1 #hj1 #ajj and #bjj #b thermometers for sand #a tank thermometer #b standard flow-plates and one dozen cartridges for same #a balance for weighing sand #f dishes1 glass or porcelain1 #d inches in diameter4 #cj4 ,the more important things for the ,plant ,inspector to watch during the manufacture of asphalt paving mixture are3 a4 ,quality and grading of the sand4 b4 ,temperature of heated sand4 c4 ,uniform quality of the refined asphalt and flux4 d4 ,temperature of melted bitumens4 e4 ,uniform consistency of asphaltic cement4 f4 ,correct ratios of sand and asphaltic cement4 g4 ,thorough mixing of materials4 #ca4 ,sand4--,the general quality and grain-size of the sand1 required by the specifications1 must be closely watched and adhered to4 ,it is hardly ever possible to secure a natural sand that will conform strictly to the theoretical composition1 but substantial compliance should be required unless the ,chief ,engineer directs otherwise4 ,after any sand has been approved for a given contract or street1 all the sand thereafter used for that street should conform closely to the standard so approved2 for any material change in the quality of the sand will change the quality of the pavement produced1 unless the proportions of the other materials are changed accordingly4 ,any material change in the sand should therefore be promptly reported to the ,chief ,engineer4 #cb4 ,sand for the sieve tests should be taken from the hot-sand box and allowed to become cold4 ,from the sample thus taken1 weigh out #ej grams4 ,arrange the nest of sieves with the ,no4 #bjj at the bottom followed by ,nos4 #ajj1 ,no4 #hj1 ,no4 #ej1 ,no4 #cj and ,no4 #aj at the top4 ,place the weighed sample upon the ,no4 #aj sieve and thoroughly shake the nest until all the sand that will1 has passed through the various sieves2 then weigh the various portions1 beginning with that which has passed the ,no4 #bjj 7deducting in each case the weight of the dish74 ,the portion remaining on the ,no4 #bjj1 is the quantity passing the ,no4 #ajj1 etc4 ,the sum of all these portions should be #ej grams1 though it will usually be slightly less because of unavoidable waste4 ,in use1 keep the sieves clean and as free as possible from adhering grains by using a bristle brush4 #cc4 ,temperature of the ,sand4--,the temperature of the heated sand should be frequently noted by plunging the thermometer into the mass4 ,it should not fall below #cae ,f4 nor exceed #cge ,f4 ,it is very important to avoid over-hot sand1 because1 in the mixer1 the very thin films of bitumen covering the hot-sand grains are readily and quickly scorched by the excessive heat in the sand4 #cd4 ,refined ,asphalt and ,fluxing ,oil4--,unless otherwise notified by the ,chief ,engineer you will assume that the stock of refined asphalt on hand at the beginning of the work has been inspected and is satisfactory4 ,you will1 however1 note the appearance of the material and the character and marking of the barrels or packages1 and will not permit the use of any new shipments of materials of different appearance or brand without authority from the ,chief ,engineer4 ,the above instructions apply also to the oil used for fluxing4 #ce4 ,ratio of ,asphalt and ,flux4--,you will frequently note and record the weight of asphalt and of flux used in charging the melting tanks4 #cf4 ,temperature in ,melting ,tanks4--,the melting kettles are usually equipped with fixed thermometers1 but their reading should be frequently checked with your detached tank thermometer4 ,you will see that the temperatures in the kettles are kept within the limits named in the specifications4 ,see that the melted asphaltic cement is kept constantly agitated as required by the specifications4 #cg4 ,uniformity of ,asphaltic ,cement4--,it is very important that the asphaltic cement shall be of uniform composition and consistency1 or hardness4 ,when the composition and consistency of the asphaltic cement to be used for the surface-course of any street has been determined upon and approved by the engineer1 you will take out and preserve a sufficiently large quantity to be used thereafter as a standard1 and each subsequent tank of cement1 before it is used1 should be tested by comparing it with this standard in the following manner1 using the flow-plate apparatus3 ,melt and fill two cartridges with the standard cement1 and two with the cement to be tested1 marking them for identification4 ,when cold1 carefully remove with a wetted dull knife any surplus cement from the ends of the cartridges so as to leave them exactly full and the metal ends clean4 ,immerse them in cold water until they are all of the same temperature4 ,then place and fasten these filled cartridges on the grooved plate with their lower ends exactly to the zero line on the plate1 the standard samples alternating with the new4 ,then place the plate1 at an inclination of about #de1 in front of a source of uniformly distributed heat1 as1 for instance1 near a steam boiler or large steam pipe1 or 7when the weather is favorable7 in the sunshine1 facing the sun4 ,leave the plate in this position until the bitumen in the cartridges shall have melted and flowed down the grooves an average of from four to five inches4 ,then measure the lengths of flow of each from the zero line on the plate4 ,if the average flow of the new samples differs more than #e per cent4 from that of the standards1 the new cement should be regarded as unsatisfactory and should be corrected by adding more asphalt or flux1 as may be required4 7,if a penetration apparatus is supplied or is available1 the penetration method may be used instead of this flow-method for determining the consistency of the cements4 ,proper instructions for its use will accompany the apparatus47 #ch4 ,ratio of ,sand and ,cement4--,when the proper ratio of sand and asphaltic cement has been determined for any street you will see that this ratio is carefully adhered to4 ,the correctness of the weighing scales used should be frequently tested4 #ci4 ,mixing4--,when the sand and asphaltic cement are properly mixed the appearance of the mass will be perfectly uniform throughout1 with every grain of sand entirely and evenly coated with cement4 ,the mixing should1 however1 be continued somewhat beyond the attainment of this condition1 so as to insure thoroughness4 ,after the proper result has been arrived at1 either the time in the mixer1 or the number of revolutions of the mixer shaft should be noted and the standard thus determined substantially adhered to thereafter4 ,with the standard mixers commonly used1 the hot sand and the filler 7dust7 should first be put into the mixer and mixed for about fifteen seconds2 then the asphaltic cement added and the mixing continued as long as necessary 7in the usual mixer not less than sixty seconds74 #dj4 ,records4--,you will keep complete records of the results of your observations and tests in a book which will be provided for the purpose1 and will make such reports to the ,engineer as he may direct4 #da4 ,inspection on the ,street4--,the leading things to be kept in mind by the street inspector1 in the laying of asphalt pavement on the street1 are the following3 a4 ,temperature of mixtures when applied to the street4 b4 ,proper preparation of the street surface before material is laid4 c4 ,laying and rolling of the binder-course4 d4 ,laying of the surface-course4 e4 ,rolling the surface-course4 #db4 ,inspector's ,equipment4--,the inspector will be supplied with the following apparatus3 #a armored thermometer reading from #bjj ,f4 to #ejj ,f4 #a graduated spatula4 #a twelve-foot straight-edge4 #a fifty-foot tape line4 #dc4 ,temperature of ,mixture4--,if proper care has been taken at the mixing plant the mixture will not arrive on the street at too high a temperature1 and your principal care will be to see that it is not laid at too low a temperature4 ,the minimum temperature named in the specifications should be adhered to4 ,while the main or interior mass of a wagon load may be well above that temperature1 the top and outer part of the load may be1 particularly in cold weather1 too cold to be safely used4 ,some of this colder portion may usually be sufficiently reheated by mixing it with the hotter material1 if properly handled in unloading2 but any material that is so cold as to be lumpy when unloaded1 or1 more particularly1 when being raked out1 should be discarded4 ,this applies to both surface and binder mixtures4 ,it must not1 however1 be overlooked that the different kinds of asphalts have different appropriate working temperatures1 and for some asphalts the minimum temperature named in the specifications may be too low4 ,the best practical guide is the manner in which the mixture behaves in raking4 ,it must always be so hot that it will1 under the rake1 break up into a uniform1 crumbling or powdery mass4 ,if it does not do this it is 7unless the mixture is excessively rich in bitumen or improperly compounded7 too cold4 #dd4 ,preparation of ,street ,surface4--,before the binder-course is laid1 all loose material1 rubbish1 street dirt and other matter foreign to the concrete surface must be removed and the concrete surface swept1 if necessary1 to properly clean it1 with street brooms4 ,neither binder nor surface mixture shall be laid upon wet surfaces4 ,before the spreading of the surface mixture on the binder the latter must be cleaned of all foreign matter and1 if necessary1 swept4 ,if the binder is covered with mud from wagons or other travel1 the surface must be scrubbed clean4 ,any part of the binder-course that may have become broken or loosened before the surface-course is applied must be taken up and new material laid in its place with the same care as the original4 #de4 ,laying ,binder-course4--,the binder mixture must be carefully spread and raked to such thickness that after being rolled it will present an even1 true surface not varying more than one-fourth inch from the intended finished surface of the binder4 ,the tendency is to lay the binder-course carelessly and to roll it insufficiently4 ,nearly the same care in raking and rolling as for the surface-course1 should be insisted upon4 ,if the binder is not thoroughly compressed before it becomes cold it is likely1 in future hot weather1 to soften and yield under heavy travel and thus to start depressions in the pavement which will increase with time4 #df4 ,laying the ,surface-course4--,the requirements of the specifications should be rigidly enforced in the laying of the surface-course4 ,joints against a cold edge of previously laid surface must be cut back until solid1 fully compressed material of full thickness is reached1 and the raw edge completely but thinly painted with liquid paving cement or pitch4 ,no masses or fragments of cold mixture1 whether of binder or surface1 must be allowed to remain on the surface of the binder in advance of the placing of the surface-course1 to be covered up by the latter4 ,such cold masses will not be compressed by the roller1 but will later1 under a hot sun and heavy travel1 yield and start depressions in the pavement4 ,the raking out requires to be properly and skilfully done4 ,the tines of the rakes must penetrate to the binder1 so that the raked material will be a uniform mass from top to bottom4 #dg4 ,rolling4--,you will insist upon the rollers being placed upon the freshly raked surface just as soon as the material will bear them without being squeezed out or displaced laterally4 ,the tendency is to keep the rollers off too long1 thus permitting the chilling of the surface and preventing its proper compression4 ,do not take the contractor's word as to how soon the rolling may be begun1 but have trials made until you are able yourself to judge4 ,the rolling by the heavy roller should be very thorough3 keep the roller at work constantly until the surface is too cold to be impressed4 ,in operating the roller lengthwise of the street begin at the gutters and work toward the center of the street4 ,cross rolling and diagonal rolling must be insisted upon wherever the width of the street will permit it4 #dh4 ,proper ,thickness and ,surface4--,while the completed surface is still warm enough to permit it1 measure the thickness of the surface-course by forcing the graduated spatula through it to the binder and noting the depth of penetration4 ,also test the trueness of the finished surface with the straight-edge1 and if found defective in either thickness of pavement or trueness of surface1 insist on more careful grading and raking on the further work4 ,try the completed gutters with water to see that they are so truly laid that puddles of water will not stand in them4 #di4 ,asphalt surface must not be laid when rain or snow is falling1 or so long as the street surfaces are wet4 ,surface mixture raked out and caught in a shower before it is well enough rolled to exclude water must be taken up and discarded4 ,unless unavoidable1 neither binder nor surface should be laid when the street surface or the air is below #dj ,f4 ,as a rule1 the lower the temperature the of air the greater is the care necessary to properly lay asphalt pavement4 #ej4 ,measure each day the area of pavement laid and record that1 and the quantity 7number of batches7 of surface mixture used1 and note any lack of uniformity in the area laid per batch4 ,,asphalt ,,block ,,pavement #ea4 ,you may assume1 unless otherwise instructed1 that the ,engineer has inspected and approved the general character of the blocks already delivered for the work1 unless their inferiority be obvious1 but you will be expected to observe them carefully as laid and to reject blocks that vary in dimensions from those permitted by the specifications1 and those that are broken1 disfigured or injured4 ,but during the progress of the work you will note the character of subsequent deliveries and report to the ,engineer any apparent change in the quality of the blocks4 ,the more important points to look after in the laying of the asphalt blocks are3 the quality and grading of the mortar bed in which the blocks are set1 and the care and accuracy of the block setting4 ,the mortar must be of cement and sand in the ratios specified1 and sufficient water used to make a medium stiff mortar2 the use of merely moistened powder must not be permitted2 and any mortar that has begun to set up before the blocks are laid and rammed must be discarded4 #eb4 ,in setting the blocks the principal requisites are3 that they be well bedded in the mortar2 that they be set so that after ramming their tops will be accurately in the pavement datum2 that they be set and pressed as closely together as possible1 levers or mauls being used to force them into close contact1 both at ends and sides4 ,,granite ,,block ,,paving #ec4 ,assuming that the foundation has been properly constructed1 the more important things for the inspector to look after are3 a4 ,the quality and shape of the blocks4 b4 ,the sand cushion4 c4 ,the setting of the blocks4 d4 ,the ramming of the blocks4 e4 ,the filling of the joints4 #ed4 ,the ,blocks4--,assuming that the general quality of the granite has been approved1 you will need only to observe and reject blocks made from soft or weathered or otherwise defective stone4 ,any material divergence of the blocks from the correct form or from the sizes specified as permissible will be readily caught by the eye as they are brought to the street1 and they can then be thrown out4 ,the proper dressing of the blocks is important and should be watched carefully4 ,while you are not expected to examine each individual block1 close observation of the blocks as they are handled and laid will enable you to detect and reject those that are materially defective in shape or dressing2 or excessively wide joints will call attention to these defects as the blocks are set4 #ee4 ,sand ,cushion4--,the sand used for the cushion bed should be moderately coarse and must be fairly clean and pure4 ,the tendency with contractors is to use any dirty sand or sandy loam available on the street4 ,such material1 especially if it becomes filled with water1 will yield under the blocks and will not support them properly4 ,the sand bed should not vary materially in thickness4 ,it should be laid and graded not more than fifty nor less than twenty feet in advance of the setting of the blocks4 #ef4 ,setting of the ,blocks4--,the blocks should be delivered in front of the block setters on the blocks already set4 ,the blocks must be set in straight courses from curb to curb1 the courses running at right angles to the street 7except at street intersections74 ,all the blocks in any one course must be of the same width4 ,each block should be so set that the whole of its bed will be seated upon sand4 ,the usual practice of block setters is to make a bed by drawing the sand into a small ridge upon which the outer edge of the block is rested1 its weight canting it against the course already laid4 ,this usually leaves a cavity under the back edge of the block which neither the subsequent joint filling or ramming closes up1 so that the block may rest permanently on only a part of its bed4 ,the practice is so fixed with block setters that it will require firmness and persistency to prevent it1 but you should insist that it be so modified as to give a solid bearing for each block over its whole base4 ,the blocks must be set solidly against each other so as to make the joints of the least possible width4 ,unless close attention is given to this the joints are likely to greatly exceed the width permitted by the specifications4 ,care should be taken that the blocks are set truly vertical so that their upper face shall be parallel to the plane of the street4 ,in setting the blocks their straightest and truest face should be placed upward so as to make the surface of the pavement as smooth and even as possible4 ,block setters are often careless about this4 ,ordinarily no grade stakes are set for the surface of the pavement and templates are seldom used1 the block setters using only their eyes to make the surface conform to the intended contour of the street4 ,this usually results in the completed street being more or less wavy and irregular1 and in a lack of regular and uniform cross-section in different parts of the street1 often very perceptible to the eye4 ,care should be taken to avoid this as much as possible4 ,straight-edges and templates1 cut to the proper curve for the surface1 should be provided and used4 #eg4 ,ramming the ,blocks4--,this part of the work is likely to be slighted unless carefully watched4 ,the important thing is to have each block equally and sufficiently rammed to bring it to a firm bearing on the sand1 as well as to bring its top to the proper grade4 ,the rammers will be disposed to touch lightly blocks or areas which if thoroughly rammed would be driven below the true surface of the pavement1 and subsequent travel may force these down1 making depressions in the surface4 ,it is a very common practice for the men working the rammers to shirk on this work by allowing the rammers to fall with little more force than that due to their own weight4 ,this should be detected and remedied4 #eh4 ,filling the ,joints4--,the specifications are quite full and clear regarding this part of the work and little further need be said4 ,care is necessary1 whether the joints be filled with gravel and bituminous cement or with grout1 to secure the complete filling of all the joints4 ,if the weather is cold at the time the work is done1 the gravel filling may become so chilled before the bituminous cement is poured that it will not flow to the bottom of the joints4 ,for this reason it is important that the cement be worked at the highest temperature that it will bear without injury4 ,if grout filling is used care is necessary to make the mortar of the right consistency4 ,if too thick it will not flow freely to the bottom of the joint2 if too thin its strength will be materially reduced4 ,experiments should be made to determine the proper consistency1 and when this is found1 the quantity of water used in making the mortar should be determined and thereafter measured out for each batch4 ,the mortar must be kept constantly stirred until used1 otherwise the sand is likely to settle to the bottom4 ,whatever filling is used1 a second and sometimes a third pouring will be necessary to completely fill the joints4 ,,brick ,,pavement #ei4 ,the matters requiring most attention in the construction of brick pavement 7assuming that the foundation is in place7 are the character and quality of the brick1 the sand cushion1 the setting of the brick1 and the filling of the joints between the brick4 #fj4 ,inspecting the ,brick4--,the examination1 testing and acceptance1 in a general way1 of the brick to be used for the work will be made in the engineer's office1 and your duty will be confined in this matter to seeing that the brick delivered and used are in accordance with the standard established and the general requirements of the specifications4 ,you can best inspect the brick as they are being laid or after they have been laid1 and before the surface has been rammed or rolled4 ,presumably the brick-setters will discard most of the unsuitable brick during the progress of their work1 particularly if they are given to understand distinctly the defects that will cause rejection4 ,as the setting is completed1 go carefully over the surface of the pavement and mark plainly all the bricks that are to be removed for defects and see that all such are taken out and replaced with good brick4 ,the principal defects that should be observed are3 soft or underburned bricks2 those that are warped or deformed so that they will not fit closely to their neighbors1 or have warped or ill-shaped tops2 those that are broken or chipped or show injurious cracks1 and those that are perceptibly wider or narrower than their neighbors in the same course4 ,soft or underburned brick may be detected with most certainty by having the contractor wet the surface of the pavement by sprinkling4 ,the soft brick will absorb more water and remain damp longer than the hard brick and can thus be readily detected4 ,this test can be applied1 however1 only to pavements the joints of which are to be filled with grout1 as bituminous filling should not be applied to brick with wet surfaces1 and to wait until they become dry after the wetting would delay the work unwarrantably4 #fa4 ,sand ,cushion4--,see that the sand used is free from foreign matter and pebbles1 as required by the specifications1 and that the sand bed is of uniform thickness1 correctly gaged1 and rolled to the true plane of the pavement1 additional sand being added or surplus removed where necessary to secure this result4 ,see that the cushion is not thereafter disturbed or1 if disturbed1 that it be restored to its original condition4 #fb4 ,setting the ,brick4--,the bricks are to be set as closely together as possible both at sides and ends1 so that the joints will not be wider than permitted by the specifications4 ,where the bricks have lugs or letters on one side1 the lug-sides shall in no case be laid together4 ,the courses must be reasonably straight entirely across the street4 ,see that the bricks in adjoining courses break joint not less than three inches4 ,brick-setters are likely to be careless about this4 ,do not permit bats to be used except where necessary at the ends of courses or to fit the pavement against street railroad rails or around manholes or other structures in the street1 and insist that this filling in shall follow immediately after the brick-setting1 and that close fits shall be made4 #fc4 ,rolling the ,pavement ,surface4--,this should be carefully and uniformly done so as to insure the even surface and contour of the pavement4 ,do not allow the roller to make sharp turns on the freshly laid brick surface as it will disturb and cant the loose brick4 ,the roller should run back onto the fully completed pavement to make any necessary turns or considerable changes of direction4 ,quick starts or stops of the roller on the fresh-laid brick should be avoided for the same reason4 #fd4 ,filling the ,joints4--,whether grout or bituminous filling be used the important thing is to get all the joints completely filled4 ,where bituminous cement is used1 if the work is done in very cool weather the brick is likely to chill the cement before it reaches the bottom of the joints unless the cement be applied as hot as possible without injuring it1 and the pouring be rapidly and carefully done4 ,if grout filling be used1 see that the mortar is made of the proper ratio of sand and cement and that it is of the proper consistency to just flow into the joints1 and that after mixing it is kept stirred until used4 ,repour all joints where necessary to completely fill them4 #fe4 ,gutters and ,expansion ,joints4--,see that the gutters are laid with longitudinal courses of brick and their joints filled with bituminous cement as provided in the specifications4 ,,wood-,,block ,,pavement #ff4 ,foundation4--,the instructions relating to the preparation of the sub-foundation and the concrete foundation already given apply to wood-block pavement4 #fg4 ,inspection of ,blocks4--,however carefully the lumber may have been inspected before its manufacture into blocks1 the subsequent seasoning1 treatment1 handling and exposure to the weather will develop many defects and you will need to observe the delivered blocks closely1 either before or after they are set1 and reject those that do not comply with the specifications4 ,the principal defects that you will be able to detect after the blocks are treated are the following3 ,southern pine blocks made of second-growth or inferior wood1 partly shown by the number of annual growth rings per inch4 ,blocks having a less number of these annual growth rings per inch than is permitted by the specifications should be rejected4 ,the treated blocks1 especially when they are exposed to the weather for some time1 are likely to develop seasoning cracks1 8shakes0 and loose knots1 not observable in the lumber1 and blocks showing these to an injurious extent should be rejected1 though in many cases the defective part may be split off and the remainder of the block used for closers4 ,if the blocks have become very dry and thoroughly seasoned out1 they should be well sprinkled with water about twenty-four hours before they are to be set1 to forestall excessive swelling and 8humping0 when a rain storm comes upon the new pavement4 #fh4 ,mortar ,bed4--,it is the common practice in preparing the mortar for the mortar bed under the blocks to simply dampen the mixed sand and cement so that it may still be spread and handled like damp sand4 ,see that sufficient water is used to make a moderately stiff mortar1 suitable for being worked with a trowel4 ,this mortar should be prepared in sufficiently small quantities at a time to insure that it will not begin to set before the blocks be placed in it and rammed4 #fi4 ,setting the ,blocks4--,the setting of the wooden blocks is a comparatively simple operation and the specifications are sufficiently full and clear for your guidance4 ,see that the blocks are so set that their tops1 after the ramming is completed1 shall be truly in the pavement datum1 without humps or depressions4 #gj4 ,filling the ,joints4--,see that the sand used is perfectly dry1 fine and clean1 and that it is swept about on the pavement until the joints are completely filled4 ,,bituminous ,,concrete ,,pavement #ga4 ,preparation of ,foundation4--,where a bituminous concrete wearing surface is to be placed upon an old pavement or ,macadam road the specifications must be closely followed4 ,a good foundation is as necessary1 if good results are to be attained1 as in the case of other pavements4 ,the dressing down of high points and the filling up of depressions in the old pavement should be carefully done1 so that the bituminous wearing surface shall be of uniform thickness1 and shall be rigidly supported at all points4 #gb4 ,bituminous ,concrete ,surface4--,the instructions given for the manufacture and laying of sheet asphalt pavement should be followed here insofar as they are applicable4 ,,hydraulic ,,concrete ,,roadway ,,pavement #gc4 ,like other structures made of hydraulic concrete1 the utility and durability of concrete roadway pavement depends largely upon the good quality of the materials used and the skill and fidelity with which the work is done4 ,it is especially important that the second1 or surface1 course of the concrete shall be made and placed in strict accordance with the specifications and that a high degree of uniformity shall be secured in the composition1 consistency and workmanship of that part of the work4 #gd4 ,sub-foundation and ,foundation4--,the preparation of the sub-foundation will be the same as for other pavements1 and the first1 or foundation course1 of concrete1 will be constructed as in the case of the concrete foundation for other pavements4 #ge4 ,material for ,surface-course4--,it may be assumed that1 in general1 the materials intended to be used on the work have been inspected and approved by the ,engineer1 but this should not prevent you from calling his attention to any defective or inferior materials that may be delivered on the street when the work is begun1 or thereafter1 and preventing the use of any materials that are not fully up to the requirements of the specifications4 #gf4 ,mixing the ,surface ,course4--,see that the cement sand and stone are proportioned accurately and that the quantity of water used with each batch is measured1 so as to make the concrete of uniform consistency4 ,do not permit any defective batches of concrete to be used in the surface-course--if suitable for the bottom course they may be used in it4 ,care in this respect is particularly necessary with machine-mixed concrete where the machine is not working normally or the men operating it are careless or unskillful4 #gg4 ,placing ,surface ,course ,concrete4--,see that the surface course is placed1 graded and rammed before the bottom course concrete begins to set4 ,this is imperative4 ,also that the concrete is distributed and graded in such a way as will not separate or segregate the mortar from the stone2 that the grading of the surface is so accurate that it will not be necessary later to add additional concrete to that already graded and rammed2 that the ramming is thorough and uniform over the whole surface1 and that the rolling is well done4 #gh4 ,expansion ,joints4--,care should be taken to have the expansion joints made as the specifications require4 ,see that they extend entirely through both courses of concrete2 that the corners are properly compacted and troweled2 that the joints are kept clean until they are filled with the bituminous cement1 and are completely filled with the cement4 #gi4 ,care of ,finished ,work4--,do not permit the completed work to be disturbed by travel over it1 and see that the concrete is kept moist1 until it shall be set up hard1 and that the street is not opened for travel until the engineer so directs4 ,,concrete ,,combined ,,curb ,,and ,,gutter #hj4 ,general4--,the specifications for the construction of ,hydraulic ,concrete ,combined ,curb and ,gutter are quite full and clear and the duty of the inspector will consist mainly in seeing that they are faithfully carried out4 #ha4 ,concrete4--,as in other concrete construction1 the utility of the work depends largely on the care and skill with which the concrete is made and placed4 ,see that the prescribed quality and ratio of materials are used and that the concrete is thoroughly mixed and properly placed in the forms and well tamped4 ,especial care is necessary to secure a continuous and satisfactory exposed surface by forking and working the mortar into contact with the forms1 which must be placed and maintained in true line and surface4 ,illustration3 ,concrete ,combined ,curb and ,gutter #hb4 ,removing ,forms4--,good judgment is required as to the proper time to remove the forms4 ,they must remain until the concrete has set hard enough to be fully self-sustaining1 but before it has set so hard that the wire brush will have no effect on the surface4 #hc4 ,corner ,protection4--,see that the metallic corner or nose piece is correctly placed and that it is solidly anchored by and fully embedded in the body of the concrete4 #hd4 ,patching4--,the practice of patching up cavities or irregularities in the exposed face of the curb and gutter with neat mortar1 or dressing the surface with dry cement1 must not be permitted4 ,if a section of the curb is found1 when the forms are removed1 to be imperfect1 the whole section must be removed and replaced4 ,,hydraulic ,,cement ,,sidewalks #he4 ,general4--,while the work of constructing concrete sidewalk is comparatively simple it is often carelessly and unskillfully done4 ,the things that need most attention by the inspector are the following3 #hf4 ,materials4--,the materials used in the work must be fully up to the quality called for by the specifications4 ,this applies more particularly to the cement and sand4 ,these are not always properly tested by the engineer and you should frequently make samples of stiff mortar 7#a cement1 #b sand7 and set them aside for observation4 ,if they do not1 in summer weather1 become very hard at the end of nine hours1 the fact should be reported to the engineer4 #hg4 ,drainage4--,see that the necessary grading is properly done and that the drainage course is made of suitable material properly compacted4 ,see that drain tiles are properly laid and connected as designed by the engineer4 ,if cinders are used for the drainage course1 see that they are screened to remove ashes and fine material1 and that they are thoroughly drenched with water at least five days before they are placed in the walk4 #hh4 ,two-course ,work4--,if the sidewalk is laid in two courses1 see that the surface-course is put on and tamped before the bottom-course concrete has begun to set4 ,this requirement must be strictly enforced4 #hi4 ,finishing the ,surface4--,dry or pure cement must not be used for trimming up or smoothing off the surface of the walk4 ,after the surface has been properly completed by straight-edge and trowel1 see that the wire broom is used as directed to remove the glaze and to slightly roughen the surface4 ,see that the expansion joints are made as specified1 and that they extend entirely through both courses of concrete4 #ij4 ,see that the walk1 after completion is properly protected from injury and from frost1 and that the concrete is kept moist until it becomes well set4 ----- ,footnote #a3 ,in specifications to be used in any particular city the official name of the city government1 as the ,city ,council1 the ,commissioners of ,public ,works1 etc41 should be used instead of this general designation4 ,footnote #b3 ,such a proviso as this seems proper in justice to both the city engineer and the contractor2 the former should not be held responsible for the acts of his assistants when they transcend the authority conferred upon them1 and the latter should be put upon his guard with reference to requirements which he is not satisfied are sanctioned or approved by the city engineer4 ,footnote #c3 ,it may be objected that this requirement is unusual and unnecessary1 since such practices are recognized as wrong1 and as presumptive of fraud and malpractice on the part both of the contractor and the inspector4 ,it cannot1 however1 be denied that in many cities such means are employed by contractors to unduly influence the action of inspectors and that not infrequently the latter not only accept1 but persistently demand1 valuable considerations from the contractor4 ,silence of the specifications on this point cannot1 of course1 be construed into consent1 but there is no good reason for the silence4 ,there should be left no excuse for misconception of the position of the city or of the engineer upon this point4 ,footnote #d3 ,this section is intended as much for the control and limitation of city officials as of contractors4 ,the practice of carelessly or purposely allowing municipal contracts to be expanded greatly beyond the stated limits or the original intended volume and cost without formal authorization by the proper municipal body in which the power to make contracts is lodged1 is dangerous and wrong and should be prohibited4 ,in one instance coming to the notice of the author a contract originally intended to cover #ej1jjj worth of work was expanded by the department head without any authority from the city council until the final estimate reached the enormous sum of over #djj1jjj4 ,footnote #e3 ,as outlined in the introduction1 these specifications are designed to secure the construction of the pavement in a proper manner1 the city assuming responsibility for the character and utility of the work4 ,the guarantee here proposed is therefore intended to cover only a proper compliance with the specifications1 for which the contractor may properly be held responsible1 and not the sufficiency or utility of the work1 if constructed according to the specifications4 ,the period of guaranty should therefore be short1 not exceeding two years4 ,footnote #f3 ,in the great majority of cases the most satisfactory and1 in the end1 the most economical foundation for a pavement is hydraulic cement concrete4 ,old paving-block foundation1 if constructed as specified in ,sect4 #cf1 will give results equally as satisfactory1 but if a fair market exists for the blocks taken up from the street1 it will usually be found more economical to sell them and construct a concrete foundation for the new pavement4 ,broken stone or gravel foundations may serve the purpose fairly well upon a street of light travel1 but it should never be used on streets of considerable or heavy travel4 ,its lower first cost is the only thing in its favor1 but this will1 in nearly every case1 be more than offset by the better service and greater durability of the pavement1 even on streets of light travel1 if laid upon an adequate hydraulic concrete foundation4 ,proper repairs to pavement surfaces cut into for pipe work1 etc41 are difficult to make and hardly ever satisfactory over broken stone foundation for the reason that the lack of cohesion in the material allows it to loosen or crumble away from under the edge of the pavement surface1 and it is difficult to restore it to its original solidity and strength4 ,the first cost saved by its use is usually not great2 for whenever its use would be permissible at all1 a comparatively thin and lean concrete would give better results1 at a very slight increase in cost4 ,to illustrate3 ,on a suburban street with light travel a concrete foundation four inches in thickness1 the concrete made with ,portland cement in the ratio of #a cement1 #d sand1 and #h stone1 would be stronger and in every way better than a foundation eight inches in depth of broken stone4 ,at the usual prices of materials and labor1 the former may cost about #j4df per sq4 yd41 and the latter about #j4dj per sq4 yd42 but for the latter there would be required cu4 yd4 more sub-foundation excavation1 worth about four cents1 so that the equivalent cost would be #j4dd per sq4 yd4 ,the difference1 two cents per sq4 yd41 is insignificant when compared with the greater value1 better service1 and greater durability of a pavement on the concrete foundation4 ,it is sometimes held that the broken stone foundation provides necessary sub-drainage4 ,but all the standard pavements are1 or soon become1 impermeable to water from the surface1 and seepage from the sub-foundation can be better taken care of by the sub-drainage specified in ,sect4 #bf1 which should usually cost not more than five cents per square yard of the pavement2 and if drainage be required1 these sub-drains should be used even with the broken stone foundation4 ,the practice of laying pavement surfaces1 particularly those of asphalt1 upon a foundation of old stone blocks1 carelessly reset1 with the joints unfilled with mortar1 is all wrong and should never be resorted to4 ,the integrity and durability of an asphalt pavement depends largely upon the strength and rigidity of its foundation2 to lay an asphalt surface1 however good1 over such an old block foundation1 is an inexcusable waste of money4 ,old stone block and cobble-stone pavements1 that have become solidified in place by long travel over them1 make a good foundation for asphalt or other pavements1 provided they can be utilized without taking up or disturbing the old pavement2 but such cases occur so rarely that they have not been considered in these specifications4 ,a thoroughly consolidated old ,mc,adam pavement1 if not worn too thin1 also makes a very satisfactory pavement foundation if it can be used undisturbed1 or by simply trimming off the high points4 ,low places in old pavements1 that are otherwise satisfactory for a foundation1 may be brought to the proper elevation with hydraulic concrete4 8,binder0 material is usually specified for this purpose in foundations for asphalt pavements1 but hydraulic concrete is both better and cheaper4 ,footnote #g3 ,the specifications for ,portland cement here given are practically those adopted by the 8,american ,society for ,testing ,materials40 ,natural ,cement4 ,while these specifications uniformly refer to the use of ,portland cement1 it is not intended to convey the idea that natural cement concrete is not suitable for pavement foundations2 on the contrary1 it may be used with entire confidence1 as the experience in a large number of cities has proven beyond question4 ,whether ,portland or natural cement shall be used is usually a question of relative cost4 ,at the present very low prices of ,portland cement in most cities1 more strength in pavement foundations can usually be obtained per dollar expended for cement1 from ,portland than from natural cement4 ,the specifications for natural cement1 as adopted by the ,american ,society for ,testing ,materials differ from those for ,portland cement in the following particulars3 ,the specific gravity shall not be less than #b4h4 ,fineness4 ,the residue left on a ,no4 #ajj sieve shall not exceed #aj per cent41 and on a ,no4 #bjj sieve shall not exceed #cj per cent4 ,setting4 ,it shall not begin to set in less than ten minutes1 nor set hard in less than thirty minutes2 but shall set hard within three hours4 ,tensile ,strength 7per sq4 in474 ,neat4 #bd hours in moist air #ej to #ajj lbs4 #g days 7#a day in air1 #f days in water7 #ajj to #bjj lbs4 #bh days 7#a day in air1 #bg days in water7 #bjj to #cjj lbs4 #a part cement1 #c parts sand4 #g days4 7#a day in air1 #f days in water7 #be to #ge lbs4 #bh days4 7#a day in air1 #bg days in water7 #ge to #aej lbs4 ,soundness4 ,standard pats kept in air and in water should remain firm and hard and show no signs of cracking or disintegration4 ,footnote #h3 ,the frequent requirement that the fine material shall be screened out1 is not necessary or advisable4 ,experiments and experience have shown conclusively that unless an unusual amount of fine material and 8dust0 be present1 or unless this fine material be allowed to separate and aggregate in masses by itself1 the resulting concrete is improved rather than deteriorated by its presence4 ,where there is an unusual excess of 8dust0 in the crushed stone1 the quantity of sand used in the concrete should be decreased accordingly4 ,footnote #i3 ,many specifications do not require this and in a number of cities where the specifications do require it1 contractors habitually neglect to comply4 ,when stone and sand are deposited directly upon the earth1 it is very difficult to avoid taking up earth and mud with the materials1 particularly when the street is wet and muddy4 ,lumps of soil and dbris unquestionably injure the concrete4 ,the cost of providing a lumber floor is comparatively small1 as the plank may be used over and over again4 ,specifications should1 therefore1 contain this requirement and it should be enforced4 ,footnote #aj3 ,the ratios of the materials may appropriately be varied with the strength and soundness of the sub-foundation1 the amount of travel on the street1 and with the thickness of foundation it is proposed to use4 ,where good materials are used and the work is properly done1 a #a3c3e concrete six inches thick is sufficient for streets of the heaviest travel4 ,for streets of light travel a #a3e3i concrete will usually give entirely satisfactory results4 ,the most economical thickness for a concrete foundation is an important consideration4 ,the strength of concrete may be said to increase1 within usual limits of practice1 with the ratio of cement in it4 ,the strength of concrete beams or slabs increases in the ratio of the square of their depth4 ,to secure a required amount of strength in a pavement foundation1 we may therefore vary the richness of the concrete and the depth of the foundation so as to secure the requisite strength at the least total cost of materials and labor4 ,this will be influenced by the cost of materials and labor in each particular locality4 ,within certain workable limits there is no reason why the same principles of proportioning the strength of a pavement foundation to the work required of it should not be applied as are employed in designing other engineering structures4 ,the practice1 usual in many cities1 of adopting general specifications requiring a standard thickness of foundation and composition of concrete1 and applying these to all streets1 regardless of the quantity and character of travel which the pavement is expected to carry1 is illogical and often very wasteful4 ,if such a standard foundation is sufficient for the streets of heaviest travel1 it is obviously a sheer waste of money to use it on the suburban streets carrying the lightest travel4 ,it is therefore better in preparing standard specifications for pavement in any city to leave blanks for the ratios of the concrete and for the thickness of the foundation1 to be filled in1 in each individual case1 as the judgment of the engineer may dictate4 ,while it is important that the foundation of any pavement shall be adequate1 it is inexcusable to waste money in providing superfluous strength4 ,for the great majority of suburban streets1 carrying but little except the local travel1 a foundation four inches thick made of good ,portland cement concrete in the ratios of #a3d3h will prove entirely satisfactory4 ,hundreds of such streets paved over a foundation of that thickness1 made of natural cement concrete in the ratios of #a3b3d can be cited where the foundation has proved entirely satisfactory4 ,the character and firmness of the sub-foundation must1 of course1 be taken into consideration in designing the foundation4 ,footnote #aa3 ,the routine here described produces better concrete with less expenditure of labor1 than the one often followed of putting all the dry materials on the concrete board before any mixing is begun4 ,the writer has proved this from actual records covering a large quantity of work4 ,footnote #ab3 ,the objections to using mortar for plastering over the concrete are3 that it is more costly than concrete2 that the two materials may1 under certain conditions1 separate and the thin mortar surface break up under travel2 that1 if permitted1 the mortar may be used to cover up defective concrete1 and that in the case of asphalt pavements the pavement surface is more likely to 8shift0 on the smooth surface of the mortar than on the rough surface of the concrete4 ,the practice of going over the fresh concrete with street brooms should not be permitted4 ,the only argument in favor of it is that it may be used to conceal defective patches in the concrete4 ,footnote #ac3 ,see foot-note#f1 p4 #bc4 ,the cost of filling the joints of old block pavement with mortar or grout is considerable4 ,it will hardly ever be less than #bj cents and may exceed #ce cents per square yard1 depending on the volume of joints and the local cost of material and labor4 ,the cost of resetting and ramming the blocks with proper care will usually be from #aj cents to #ab cents per square yard1 so that the cost of the foundation1 exclusive of the value of the blocks1 may vary from #cj cents to #dg cents per square yard4 ,as a good concrete foundation #f inches in depth can be laid for from #gj to #ij cents per square yard1 it is obvious that if the old blocks can be sold for as much as the difference between the cost of the old block and the concrete foundation1 nothing will be saved by using the old block foundation4 ,in at least one city1 asphalt pavement has been extensively laid over old stone block foundation relaid in a very careless manner1 the joints being filled usually with the old sand or loam found in the street4 ,this practice cannot be too strongly condemned4 ,asphalt pavement surfaces resting on such a foundation are necessarily short-lived and unsatisfactory4 ,the practice of opening the street to travel for a period after the blocks are relaid and before the asphalt surface is applied1 helps1 under favorable conditions1 to consolidate the foundation1 but does not remove the objections to it4 ,if heavy rains intervene1 the sub-foundation becomes saturated with water1 and its resistance so reduced that the stone blocks settle out of shape1 particularly in soft spots1 and they are usually hastily raised and reset just before the asphalt surface is applied4 ,the result is an insecure foundation fatal to the durability and usefulness of the pavement4 ,footnote #ad3 ,where there is a possibility that gravel may be used1 the contractor should be asked to name prices for the gravel foundation as well as the stone foundation1 since1 unless this be done1 the change from the one material to the other might be held to be illegal4 ,footnote #ae3 ,there has been much discussion as to the suitableness of these oil asphalts1 called 8residual pitches10 for use in making asphalt pavements4 ,when properly prepared from suitable asphaltic oils1 so as to comply with the specifications here given1 there can be no doubt that good pavements can be made with them4 ,but as they appear on the market1 being usually produced at different localities and refineries from crude oils of differing qualities1 distilled by somewhat differing methods1 and usually at temperatures of from #ijj degrees to #abjj degrees1 they are likely to vary so greatly in quality as to make their use inadvisable without careful technical inspection4 ,unless1 therefore1 the engineer is prepared to make1 or to have such inspection made1 it is hardly wise or safe to permit their use4 ,they stand1 in this respect1 upon a footing different from the better-known natural asphalts obtained from large deposits of practically uniform character and quality1 where the simpler process of refining is less likely to effect injuriously the chemical quality of the material4 ,it may be confidently predicted that any of these 8residual pitches0 which comply with these specifications will1 if properly handled1 make a good pavement4 ,footnote #af3 ,the possibility that some of these compounds or artificial asphalts1 may be suitable for use in pavements is not denied4 ,but in the absence of a fuller knowledge of them than we now have1 and in the light of present experience1 the only safe course is to reject them4 ,footnote #ag3 ,it is not intended here to enter into an extended discussion of the fact that some asphalts are injuriously affected by water1 and the bearing which this fact should have upon the selection of an asphalt for pavement purposes4 ,there can be no doubt that modern treatment and methods of construction have tended to diminish but not wholly to prevent the disintegrating effect of water upon pavements made with such asphalt1 and if the engineer could be certain that his pavements would be constructed by contractors guided by long experience and the best expert advice1 he might perhaps safely disregard this provision4 ,since in practice he can have no such assurance1 the provision is a wise one and it does not involve any serious or material hardship to the contractor4 ,footnote #ah3 ,it is now well recognized that the character and quality of the sand used is one of the most important elements in determining the utility and durability of an asphalt pavement4 ,a satisfactory sand should be insisted on1 even if it involves a very considerable increase in the first cost of the work4 ,while our knowledge of the subject is not complete1 experience seems to indicate pretty clearly that a sand of the quality and size-grading here specified as typical1 may be depended upon to produce a good pavement4 ,footnote #ai3 ,the use of ,portland cement in surface mixtures to be laid on streets of heavy travel1 or those exposed to damp foundations1 is very strongly recommended4 ,on streets of the heaviest travel1 or where the pavement will be exposed to unfavorable conditions of dampness1 particularly if the pulverized stone is not very finely ground1 the ,portland cement may constitute twenty per cent4 of the pulverized material1 or 8dust10 as it is commonly called4 ,ordinarily from five to ten per cent4 may be used to advantage on all streets of moderately heavy travel4 ,footnote #bj3 ,for determining the consistency of individual batches of asphalt paving cement with a standard sample1 the flow-plate method is most convenient and sufficiently accurate4 ,for a description of the latest improved form of this apparatus see ,engineering ,news of ,aug4 #bb1 #aiab1 p4 #cdg4 ,it can only be used1 however1 where the cements to be compared are of the same general composition--the same refined asphalt and tempering agent--as the standard4 ,footnote #ba3 ,the practical value of the exact determination of the ductility of asphalt paving cements is regarded by the author as not well established4 ,it is customary1 however1 in most recent specifications to require it4 ,some asphaltic cements that have been quite successfully used for pavements have not complied with such requirements1 while good coal-tar pitches will greatly exceed them4 ,where this test is used the usual specification requires that a briquette of asphaltic cement having a cross-section of one square centimeter1 at penetration #ej1 shall elongate to the extent of not less than #bj nor more than #he centimeters at #gg ,f4 ,if the asphaltic cement varies from #ej penetration an increase or decrease of at least #b centimeters will be required for each five points above or below #ej penetration 7,dow apparatus to be used74 ,footnote #bb3 ,it should be noted1 in a general way1 that there is quite a difference in the temperature to which different asphalts may be safely subjected4 ,trinidad asphalt1 and the ,california residual pitches1 will not be injured by the higher range of temperatures named in these specifications1 while ,bermudez and some other asphalts should be worked at as nearly as possible to the lower range of temperatures named4 ,the relative amount of loss of the different asphalts when exposed for seven hours to the temperature of #cbe degrees 7,sect4 #dd7 will supply a rough practical guide as to the temperature permissible--the greater the loss1 the closer should the lower range of temperatures be adhered to4 ,footnote #bc3 ,the open base-course1 or 8binder10 composed only of crushed stone1 coated with pitch or asphaltic cement1 extensively and almost exclusively used up to a recent date1 is no longer advocated by the best authorities on asphalt pavements4 ,the aim is now to make the base-course as dense and strong as the surface-course4 ,footnote #bd3 ,the importance of proper and thorough rolling is not usually fully appreciated1 and this part of the work is often shirked by the contractor4 ,not only should the heavy roller be at work as soon as the material will bear it1 but the roller should1 when work is progressing regularly1 be kept at work all the time4 ,it is a safe motto that the final rolling cannot be overdone4 ,footnote #be3 ,there is still a wide difference of opinion as to the advisability of laying the asphalt surface directly against the rail1 many engineers preferring to set one or more courses of paving brick1 or stone paving blocks between the rail and the edge of the asphalt4 ,the writer's experience is to the effect that1 if the work is properly done1 the first-named form of construction is preferable4 ,if the asphalt be laid against a rail so cold that the asphalt material in contact with or near the rail is chilled before it can be compressed1 the work will necessarily be unsatisfactory4 ,as to durability1 wheels following the line of the rail or of the paving blocks will sooner or later form a rut in the asphalt which will require repair--and there is not much difference in the results4 ,the attempts to prevent the formation of ruts by setting blocks alternately as headers and stretchers is not always successful1 even when the work is well done1 and the difficulty of properly compressing the tongues of asphalt between the headers is so great that it is usually not well done4 ,the asphalt settles under travel or is gouged out1 leaving a streak of rough pavement1 and the difficulty and cost of repairs is considerably increased4 ,when paving blocks or bricks are used1 they should be firmly and carefully set in the concrete foundation4 ,probably the most satisfactory construction of this kind consists of two or three lines of the best paving brick set with their length parallel to the rail4 ,it is somewhat easier to get at and repair rail joints with this construction4 ,footnote #bf3 ,the practice of laying asphalt block pavement upon crushed stone1 or a sand foundation1 on streets carrying a considerable travel1 is inadvisable4 ,see foot-note#f1 page #bc4 ,footnote #bg3 ,hard limestone may be used where trap is not procurable except at a prohibitive cost2 but unless the difference in cost is very great the trap will be the most economical in the end4 ,footnote #bh3 ,the pressure commonly specified is #ejjj lbs per4 square inch1 but recent investigations make it doubtful if that pressure is ever attained1 or is1 indeed1 practicable with any presses so far constructed4 ,footnote #bi3 ,asphalt blocks are now very commonly laid upon their sides1 even where they are made as thin as two inches1 on streets carrying very considerable travel4 ,the practice is not to be recommended unless the blocks are at least four inches thick4 ,blocks two inches thick will give good service on private driveways and streets of quite light travel4 ,footnote #cj3 ,granite block pavement is1 as a rule1 used upon1 and appropriate for streets of the heaviest class of travel1 and should1 therefore1 be provided with the best and strongest foundation4 ,it is nearly always poor economy to lay granite blocks upon a broken stone1 gravel1 or sand foundation4 ,footnote #ca3 ,like other stones1 granite from various localities differs widely in strength1 hardness and brittleness4 ,great hardness1 accompanied with comparative brittleness1 is not desirable in granite for paving blocks4 ,such material usually polishes by travel and becomes quite slippery1 and it is likely to become 8turtle-backed10 that is1 the corners are likely to be chipped off or worn off1 making the pavement very rough and uneven4 ,the quality of the granite to be used in any one city is generally determined by the available supply1 and specifications must be drawn with reference thereto4 ,footnote #cb3 ,except on streets of excessively heavy travel there seems to be no good reason for making the blocks more than five inches deep4 ,blocks of this depth are quite sure to become deformed by irregular wear before the pavement will need to be renewed4 ,footnote #cc3 ,the widths of joints here specified as allowable are based upon the assumption that they will be filled with ,portland cement grout as specified in ,sect4 #ge4 ,if this grout filling is used narrower joints are not necessary1 as the grout has sufficient strength to support the corners of the blocks1 and sufficient hardness to resist the wear of travel 7largely protected as it is by the blocks themselves7 and to cause the blocks to wear down quite evenly4 ,in many ,european cities the specifications require much closer joints4 ,the granite there available appears to break out naturally to truer lines and better surfaces than that used in the ,eastern states1 at least1 so that the cost of dressing the blocks abroad is not as great as here4 ,the ,city of ,new ,york has recently adopted specifications for 8,special ,improved0 ,granite ,block pavement intended to approximate the ,liverpool standard4 ,these require that the blocks shall be not less than #f nor more than ten inches long1 not less than #c nor more than #d inches wide and five inches in depth4 8,the blocks are to be rectangular with tops and sides uniform in thickness1 to lay closely1 and with fair and true surface1 free from bunches and so cut or dressed that when laid stone to stone the joints shall not exceed of one inch4 ,the head of the block shall be so cut that it shall not have more than one-quarter of an inch depression from a straight-edge laid in any direction across the head and held parallel to the general surface of the block40 ,the joints are filled with bituminous cement4 ,the above specification is very difficult to meet from the granite available to ,new ,york without excessive and expensive cutting1 and examination of the pavements laid under these specifications shows that the joints greatly exceed the width specified4 ,it is believed that equally good results may be secured by permitting somewhat wider joints filled with grout1 and the cost would be materially reduced4 ,footnote #cd3 ,the most satisfactory arrangement of courses at street intersections is that shown by ,fig4 #ad1 page #bjh1 ,tillson's ,street ,pavements and ,paving ,materials1 #b;d edition4 ,footnote #ce3 ,the practice of filling the joints with gravel to a depth of one inch or more before the blocks are rammed is of doubtful utility4 ,if the blocks are set closely against each other they will be well held in place while the ramming proceeds4 ,in practice it is hardly possible to closely gage the depth of such preliminary gravel filling1 and the top or final filling whether of grout or of gravel and bituminous cement1 is likely to vary greatly in depth1 and the lateral support of the blocks is thus likely to vary in strength and rigidity4 ,footnote #cf3 ,it has been the almost universal custom1 in this country at least1 to fill the joints in granite paving either with gravel alone or with gravel and bituminous cement4 ,but the reasons that have led engineers to prefer grout filling for brick pavements apply with equal force to granite pavement4 ,it makes a stronger and harder filling than the gravel and bituminous cement1 and gives a better support to the edges of the paving blocks1 thus tending to prevent chipping and 8turtle-backing0 in the pavement4 ,it is also a materially cheaper filling than the gravel and bituminous cement4 ,but to provide for the expansion and contraction of the pavement by changes of temperature1 it is desirable that a strip in the gutters1 and an occasional strip across the whole street1 shall be filled with the more yielding material1 as specified4 ,footnote #cg3 ,the object of adding asphalt and ,portland cement is to make the cement stronger and less susceptible to changes of temperature4 ,pure coal-tar pitch is very brittle at low temperatures1 and is liable to flow from the crown of the street to the gutters in hot summer weather4 ,a cement made as here specified is not only much stronger and less brittle in cold weather1 but requires a materially higher temperature to cause it to flow than does pure pitch4 ,footnote #ch3 ,as the wheels of vehicles frequently follow along the lines of the rails1 thus concentrating their effect on a narrow strip near the rails1 and as the continuous joint against the rail makes the pavement weaker there1 the mortar bed1 and the greater care in setting the blocks along and near the rail are advisable4 ,footnote #ci3 ,if the joints are parallel to the direction of travel on the street the wheels of vehicles are more likely to abrade or break off the corners of the stone and form incipient ruts4 ,footnote #dj3 ,these specifications conform in most particulars to those adopted by the 8,association for ,standardizing ,paving ,specifications10 and are substantially the same as those recommended by the 8,national ,paving ,brick ,manufacturers' ,association0 though they differ in some details from each4 ,the latest specifications adopted by the ,association for ,standardizing ,paving ,specifications are very full and satisfactory and are to be highly commended4 ,footnote #da3 ,here again a good concrete foundation is recommended1 as being in the end the most satisfactory and economical4 ,see foot-note#f1 page #bc4 ,footnote #db3 ,the ,association for ,standardizing ,paving ,specifications 7,new ,orleans meeting7 adopted a standard size for paving bricks and blocks as follows3 ,paving brick1 #h inches long1 #b inches wide and #d inches in depth4 ,paving blocks #h inches long1 #c inches wide and #d inches deep4 ,there seems to be no sufficient reason for confining the brick to these dimensions4 ,footnote #dc3 ,the specifications of the ,association for ,standardizing ,paving ,specifications require that all paving brick shall have lugs on one side1 and allow a projection of inch from the face of the brick4 ,the object is to provide a wider joint between the bricks in order to facilitate the filling of the joints4 ,the author does not believe these lugs necessary1 nor that brick without lugs1 but otherwise acceptable1 should be excluded4 ,it is certain that many of the best brick pavements ever constructed have been built of bricks without lugs4 ,if lugs are required they should preferably not project more than one-eighth inch4 ,the same reasons that make narrow joints desirable in other block pavements apply equally to brick pavements4 ,footnote #dd3 ,the ,a4 ,s4 ,p4 ,s4 ,specifications permit a loss of #bb with the block size1 but do not name a permissible loss for 8brick0 size4 ,footnote #de3 ,absorption of less than one-half of one per cent41 usually indicates that a shale brick has been over-burned1 resulting in increased brittleness4 ,footnote #df3 ,the absorption test is falling into disfavor1 particularly with the manufacturers4 ,the author believes that it possesses a distinct value and should be retained4 ,footnote #dg3 ,the object of this is to make a gutter offering less obstruction to the flow of water4 ,footnote #dh3 ,this is the simplest and most effective way to detect soft and underburned brick4 ,footnote #di3 ,if the joints are to be filled with bituminous cement1 substitute for sections #ij and #ia the following3 ,directly after the completion of the rolling and ramming1 all the joints in the brick pavement and between it and the curbing1 manholes or other structures1 shall be filled with a bituminous cement in the following manner3 ,the bituminous cement shall be composed1 by weight1 of one hundred 7#ajj7 parts of straight-run coal-tar pitch commercially known as number four and twenty 7#bj7 parts of refined ,trinidad asphalt melted and thoroughly mixed together at a temperature of about #cej ,f41 to which shall be added twenty 7#bj7 parts of dry ,portland cement1 which shall be thoroughly incorporated with the hot bitumen until a homogeneous mass is produced1 and kept agitated so as to prevent settlement or separation until the cement is used4 ,if another asphalt is used instead of ,trinidad the quantity added to the pitch must be sufficient so that the cement will not flow at a temperature lower than one hundred and twenty-five degrees ,fahrenheit 7#abe ,f474 ,this cement while at a temperature of about #cbe degrees ,f4 shall then be poured from a spouted vessel into all joints and vacancies in the pavement until they are completely filled1 repouring being resorted to if necessary to accomplish the complete filling of the joints4 ,after the joints are thus filled a layer of sand one-half inch thick will be spread over the whole surface of the pavement and allowed to remain until the engineer shall direct its removal4 ,footnote #ej3 ,the bituminous-cement joints are principally for the purpose of providing for the expansion of the pavement in very hot weather4 ,experience seems to have proved that cement grout is1 everything considered1 the best and cheapest filling for the joints in brick pavement4 ,if the filling is properly done1 the edges of the brick are supported and the corners do not chip off4 ,with the expansion joints provided at intervals by the bituminous-filled joints1 the curbs will not be forced out of line1 nor will the pavement be raised from its sand bed by expansion1 causing the rumbling sound sometimes noticed4 ,where grout filling is used there seems to be no necessity for covering the surface of the pavement with sand1 as is usually done1 provided the grout is kept damp4 ,footnote #ea3 ,since immunity from early natural decay is secured by preservative treatment1 the important requisite for wood paving blocks is capacity to withstand the wear and tear of the travel on the street4 ,we have as yet no very satisfactory data as to the ability of the various species of wood to endure the somewhat peculiar and special duty to which paving blocks are subjected4 ,the test which seems to most nearly approach to what is wanted is that of crushing strength1 when the force is applied to the end of the sample1 parallel to its fibers2 but this does not embrace the effect of impact to which paving blocks are subjected under street travel4 ,whether this may be considered a function of the end-crushing strength or not is an open question1 though there seems good reason to believe that it will prove to be so2 and if so1 there is no good reason why woods of substantially equal strength under the end-crushing test should not show about the same endurance under street travel1 independent of the element of natural durability1 which is practically eliminated by preservative treatment4 ,the end-crushing strength per square inch of some of the kinds of timber named as acceptable is about as follows3 ,southern long-leaved yellow pine #fijj lbs4 ,lob-lolly pine #fejj lbs4 ,short-leaved pine #eijj lbs4 ,cuban pine #gijj lbs4 ,norway pine #fgjj lbs4 ,red gum #gajj lbs4 ,it was formerly very customary to specify that only ,southern long-leaved yellow pine might be used for paving blocks1 though this requirement was seldom strictly enforced4 ,the fact is1 that with the exception of the test based upon the number of growth rings per inch1 it requires an expert knowledge1 acquired only by long experience1 to distinguish with certainty the species of ,southern pine from the appearance of the lumber alone4 ,it is now almost impossible to obtain in the market shipments of strictly long-leaved yellow pine1 and while that wood is undoubtedly superior to the other pine timbers for paving blocks it seems useless to specify its exclusive use1 or to propose specifications designed to exclude lumber made from other species of pine4 ,it was doubtless the recognition of this situation that influenced the ,association for ,standardizing ,paving ,specifications1 at its last 7,new ,orleans7 convention to adopt a specification which practically admits everything known in the market as 8,southern yellow pine0 having annual growth rings averaging less than eight to the inch and excluding all timber having less than six rings to the inch4 ,within these limits these specifications practically admit all pine lumber shipped from ,southern mills4 ,the specifications here proposed1 by limiting the number of growth rings to nine per inch1 would not confine the lumber to true long-leaved yellow pine1 but would secure a more mature and solid quality of lumber4 ,it is true1 however1 that both these specifications and those adopted by the ,a4 ,s4 ,p4 ,c4 exclude most 8,cuban pine0 lumber which is very rapid growing1 the growth rings often numbering but three or four to the inch1 though the strength of the wood from this species indicates that it may safely be used for pavement4 ,footnote #eb3 ,the question of the most economical depth for wood paving blocks is as yet unsettled4 ,in ,new ,york ,city1 blocks #c inches in depth are adopted as the standard and are being used on streets of the heaviest travel1 the practice of ,berlin1 ,paris and other foreign cities being thus followed4 ,the arguments in favor of these short blocks are lower first cost1 and that1 with much deeper blocks1 the usual uneven wear of a wood pavement will make it so rough as to require removal before the blocks are worn down so as to be split up and dislodged from their places4 ,while reliable data on these points are wanting1 it seems to the writer very unwise to use such short blocks on streets of heavy travel1 and he would recommend that the minimum length for use on such streets be #d inches1 and he would prefer #e inches4 ,on streets of light travel a length of #c inches should be satisfactory4 ,recent observations on heavy travelled streets in ,new ,york indicate that when long-leaved yellow pine blocks become worn down to a remaining depth of about #b inches they split up into fine slivers and the pavement goes to pieces4 ,footnote #ec3 ,most of the more recent specifications require the use of a heavy oil1 said to be composed of creosote oil with an admixture of refined tar1 on the ground that the tar is necessary as a water-proofing agent to prevent the creosote oil from being dissolved out by water or evaporated into the air4 ,it is claimed that if moisture can thus be excluded from entering the wood1 decay will be prevented1 even in the absence of the antiseptic elements of creosote oil4 ,it is not intended to discuss this matter at length here4 ,we know from long experience that genuine creosote oil is the best preservative of wood so far found2 also that creosoted piles have stood in tidal waters1 alternately exposed to water and air1 for twenty-five years and still retain sufficient creosote oil to resist the ,teredo--a very severe test4 ,why experiment with a comparatively untried material1 particularly when it costs as much as the genuine creosote oil1 is rather more difficult to force into the wood1 and has some admitted objectionable qualities8 ,footnote #ed3 ,it is a common practice of contractors in some cities1 in the laying of both wood-block and asphalt block pavement1 where a mortar bed is called for1 to substitute a bed of mixed sand and cement1 dampened only to such a degree as will make the mass pulverulent like damp sand1 the claim being made that ordinary mortar cannot be spread and gaged properly4 ,this claim is unfounded4 ,the objection to the practice is that the dampened mixture does not contain sufficient water to cause the cement to set1 and with the practically water-tight paving surface1 does not receive1 even in rainy weather1 the necessary amount of water4 ,if the weather be dry1 the small quantity of moisture in the mixture quickly evaporates1 leaving the so-called mortar bed not much better than a layer of sand alone4 ,the writer has found such alleged mortar dry and unset two weeks after the pavement had been completed4 ,if real mortar is not to be used1 a layer of sand might almost as well be substituted at first4 ,footnote #ee3 ,in a number of cities the specifications require the joints in wood-block pavement to be filled with ,portland cement grout4 ,if the blocks are set as closely together as they should be1 the joints will be so narrow that no grout1 thick enough in consistency to be of value1 will enter them1 except for a short distance down from the top1 the remaining depth of the joints remaining unfilled4 ,an examination of any well-laid wood-block pavement soon after it has been attempted to fill the joints with grout will verify this statement4 ,furthermore1 the oil which exudes from the blocks1 acting on the thin films of grout1 seems to deteriorate the mortar and to render it practically inert4 ,on the contrary1 fine dry sand will readily run into and completely fill the joints1 and under travel the joints will soon become impervious to water4 ,the sand filling is therefore regarded as better1 and it costs less than the grout filling4 ,footnote #ef3 ,wherever an old pavement or macadam road can be utilized it makes an excellent foundation for a pavement of this kind1 provided it is not in too dilapidated a condition1 extends from curb to curb1 and its surface conforms near enough to the desired street surface so that the necessary changes and repairs will not be too expensive4 ,where the new pavement is expected to carry quite a heavy travel it is not advisable to use plain crushed stone for filling depressions and leveling up the surface4 ,it is difficult1 even where proper care is used1 to make such patches of broken stone as firm and strong as the adjoining old pavement1 which is a necessary condition to secure satisfactory results2 for if the masses of broken stone yield under travel1 slight depressions will form over them in the bituminous surface1 which will in time become holes requiring repairs4 ,the #a3d3i concrete specified for this work is not very much more expensive than plain broken stone1 it will not shift or break up under travel1 and will in the end prove a better investment4 ,footnote #eg3 ,where a new foundation is required broken stone or macadam is most frequently used for bituminous concrete pavements4 ,unless such foundations are constructed in the same way and with about the same care as is necessary for a macadam road it is liable to prove unsatisfactory4 ,under the very heavy wheel loads that may occasionally pass over the streets1 imperfectly compacted broken stone is likely to shift sufficiently to start incipient ruts which will enlarge and in time necessitate expensive repairs4 ,such conditions are frequently seen on bituminous concrete pavements subjected to heavy travel4 ,these pavements1 like sheet asphalt pavements1 require a foundation that will be absolutely unyielding under travel4 ,for this reason a concrete foundation will generally be found more economical in the long run than a broken stone foundation4 ,the increased first cost per square yard is not very great and this additional money will in most cases prove a good investment4 ,at the usual prices of material and labor a square yard of #d inch concrete should cost about #ej cents1 while a properly constructed broken stone foundation #f inches thick 7which would not nearly equal in strength and rigidity #d inches of concrete7 would cost about #de cents per square yard4 ,considering the much greater durability and lower cost of repairs of the pavement on the concrete foundation1 this small additional cost is not worth consideration4 ,while the specifications are made to cover the three kinds of foundation1 it is assumed that the kind of foundation to be used will be decided in advance1 and that the part of these specifications relating to the others kinds of foundation will1 in actual use be omitted4 ,footnote #eh3 ,a bituminous cement composed largely of coal-tar pitch has heretofore been most used in pavements of this character4 ,it is not denied that very good pavements have been1 and can be built with this material1 but the superiority of the asphaltic cement here specified is so great that it is true economy to use it4 ,the difference in cost at prevailing prices of material will be ten to twelve cents per square yard4 ,the greater durability and serviceability of the pavement made with the asphaltic cement will1 particularly on streets of comparatively heavy travel1 far more than justify this additional cost4 ,footnote #ei3 ,hydraulic concrete pavement is to be recommended only for country roadways and for city streets of very moderate travel4 ,while our experience with this kind of pavement is yet limited there is reason to believe from the nature of the material that it will not prove to be a satisfactory or economical pavement for streets of heavy travel4 ,but in all cities and towns there are many residence streets where the travel is very light1 and yet where a permanent pavement is wanted and warranted4 ,for these1 it is believed that a properly constructed concrete pavement will prove very satisfactory and durable1 and the low cost at which it can be constructed should make it very attractive to city officials and property owners4 ,the author has advocated its use under such conditions for many years 7see ,engineering ,news1 ,july #bast1 #aijd74 ,like other composite pavements its utility and durability will depend largely upon the good quality of the materials used and the skill and thoroughness with which the work is done4 ,the specifications here offered are the result of the observation and experience of the author1 and it is believed that pavements laid in accordance with them will give very satisfactory results4 ,footnote #fj3 ,a number of engineers advocate the construction of concrete pavement in one homogeneous course1 and quite a number of pavements have been constructed in this way4 ,like any other composite pavement1 it is called upon to perform two functions2 to safely sustain the weight of loads passing over it1 and to resist wear and abrasion of its surface4 ,a material and form of construction that meets the first requirement may not meet the second4 ,experience has proved that ordinary #a3c3f concrete makes an entirely satisfactory foundation for any pavement1 but it lacks the hardness and strength to successfully resist the surface abrasion of travel4 ,to secure this quality a richer and harder concrete is called for1 but it is unnecessary that the foundation should be equally hard4 ,to construct the pavement in two courses as here specified would seem to be the logical way1 especially as it decreases the total cost1 and should make a more durable pavement4 ,footnote #fa3 ,some engineers advocate a greater total thickness of the pavement than is here specified 7#f inches74 ,considering that this pavement should never be used on heavy traveled streets1 a total thickness of concrete of six inches will have ample strength to carry the loads to which it will be subjected4 ,if so1 it is a useless waste of money to increase the thickness of the concrete4 ,footnote #fb3 ,the use of limestone for the top course 7unless it is of very superior quality7 is not advisable or economical unless the cost of trap rock is so high as to be prohibitive1 which1 considering its superior durability under the wear of travel1 will not often be the case4 ,footnote #fc3 ,it is advisable to remove the screenings from this surface mixture for two reasons3 first1 to secure greater uniformity of composition4 ,if the screenings are allowed to remain in the aggregate1 there is danger of segregation into patches of different sized aggregate and different ratios of materials1 which it is very important to avoid1 and second1 the small fragments of stone are more likely to be crushed under the concentrated weight of wheels than the larger masses1 and to thus start disintegration4 ,lack of uniformity in the composition and homogeneity in this surface-course concrete is especially to be guarded against1 otherwise the surface of the pavement will wear unevenly and depressions and ruts are likely to result4 ,footnote #fd3 ,the ideal composition of this surface-course concrete is one where the stone forms the largest possible part of the mass consistent with sufficient mortar to fill the voids and thoroughly bind the fragments of stone together4 ,footnote #fe3 ,the importance of securing high quality and great uniformity in the surface course cannot be urged too strongly4 ,footnote #ff3 ,this requirement must be strictly enforced4 ,otherwise there will be danger that the two courses may not properly adhere to each other4 ,it is the writer's experience that if this rule is observed there will be no danger of the two courses separating4 ,footnote #fg3 ,the purpose of this rolling is mainly to evenly compress the mass and thus secure its uniform density4 ,it also produces a truer surface than can usually be secured by ramming alone4 ,footnote #fh3 ,among engineers there is quite a wide difference of opinion as to the proper spacing of expansion joints1 and1 in fact1 as to the necessity or advisability of providing them at all4 ,it has been suggested that it might be better to omit them entirely1 allowing the pavement to form its own expansion joints by cracking along lines where natural forces dictate4 ,such cracks by their irregularity give a bad appearance to the surface1 but observation seems to indicate that the edges of these natural joints wear as well as those made by expansion joints4 ,further observation and experience is needed in the matter4 ,in most concrete it is known that some contraction takes place during the setting of the cement1 regardless of temperature changes1 and cracking is probably due as much to this permanent contraction as to that caused by low temperature4 ,the coefficient of expansion of concrete by heat is variable but so small that expansion joints inch wide every fifty feet along the street should provide for temperature changes4 ,footnote #fi3 ,if the expansion joints are not thus filled with bituminous cement they will become filled and packed with incompressible stone1 sand1 etc41 that will not permit expansion4 ,footnote #gj3 ,the practical value of oiling concrete pavements has not yet been determined by sufficient experience4 ,there is reason1 however1 to believe that the slight coating of bitumen will materially preserve the surface from abrasion and that its benefit will thus be greater than its cost4 ,it will also tend to prevent the very slight dust that might otherwise exist on the pavement4 ,footnote #ga3 ,in this class of pavements the contractor or promoter may properly be required to assume responsibility for the character and utility of the work produced1 and the municipal authorities should assume no part of such responsibility4 ,footnote #gb3 ,upon the general subject of time guarantees of municipal work1 see ,chapter ,,xi1 8,municipal ,public ,works10 by the author4 ,footnote #gc3 ,concrete combined curb and gutter is suitable for use on the great majority of residence streets1 and others where the travel is not excessive1 or where it will not be subjected to specially severe use1 as on business streets where heavy vehicles are likely to be often backed against the curb4 ,if properly constructed it will have sufficient hardness and strength to withstand all ordinary usage2 it makes a better appearance1 particularly on residence streets1 than any other kind of curbing1 is durable1 and is usually less expensive than any other suitable1 equally durable and equally well-finished curbing of natural stone1 since the gutter displaces an equal area of pavement4 ,footnote #gd3 ,the sketch here presented conforms pretty closely to usual practice except in the width of the gutter4 ,it is not uncommon to make the gutter from two to three feet wide4 ,this is not necessary or desirable4 ,a width of #ae to #ah inches forms a sufficient gutter to carry away all drainage except during very heavy rainfalls4 ,where the gutter projects out into the street sufficiently far to be exposed to large numbers of heavily loaded wheels the outer corner is likely to become broken off or unduly abraded4 ,footnote #ge3 ,curbing of all kinds is more likely to be injured by freezing and the heaving of frost under and around it than from any other cause4 ,good drainage is the best protection against such injury4 ,it is important that these drains shall be connected with sewers1 drains or other outlets1 so that water will not stand in them4 ,footnote #gf3 ,the most notable departure of these specifications from usual practice is the use of a solid body of rich1 homogeneous concrete for the whole section of the structure1 thus avoiding the use of two courses and qualities of concrete--the core concrete and the facing4 ,the most common cause of failure of concrete curbs and gutters is the separation1 more or less1 of the facing from the core concrete4 ,without doubt this can be prevented by the use of proper materials1 careful work1 and the strict observance of the rule that the facing course must be applied before the core concrete has begun to set4 ,but it is difficult to always secure these favorable conditions4 ,computation will show that the difference in cost of materials1 between the usual two-course construction and a single body of rich concrete throughout1 is not very great1 while the saving in cost of labor is so considerable as to make the actual difference in cost of the two types very small4 ,there can be no doubt that the simpler construction and the consequent greater certainty of securing a durable and satisfactory job is greatly in favor of the construction here recommended4 ,footnote #gg3 ,the appearance of 8hair cracks0 on the surface of rich concrete1 finished by troweling1 and the blotched appearance of the surface of concrete curbing1 are usually caused by improper finishing4 ,the glazed surface produced by troweling1 particularly where pure1 dry cement or neat mortar is applied is almost sure to develop hair cracks1 and the varying texture of the surface is likely to absorb water unevenly and thus produce1 in time1 the unevenly colored or blotched surface so often seen4 ,footnote #gh3 ,the utility and durability of hydraulic concrete sidewalks depends largely on the quality of materials and workmanship employed in the work4 ,too frequently1 specifications for this work are not sufficiently full1 or not prepared with the requisite care1 or the work is not properly supervised or inspected while in progress4 ,the aggregate importance and cost of this sidewalk work in our cities warrants more care and attention than it generally receives4 ,footnote #gi3 ,determined by the thickness of the drainage course adopted4 ,footnote #hj3 ,it is customary in many cities to require that the drainage course under the concrete shall have a depth of twelve or more inches4 ,this deep-drainage is designed to prevent the heaving of the sidewalk by freezing4 ,experience seems to prove that this is not necessary1 particularly if tile drains are provided to carry off the water from the drainage course1 as specified4 ,comparatively dry material1 even earth1 does not heave with freezing2 on the other hand1 if the material and the trench in which it is placed is wholly or partly filled with water1 heaving is liable to occur in severe freezing weather1 whatever the depth of the drainage course4 ,experience has proven1 however1 that four inches of drainage material is sufficient if the water is drained out of it1 while if allowed to stand saturated with water1 deeper drainage will give little if any better results4 ,where the soil is sandy or the natural drainage is otherwise good1 no drainage course is necessary4 ,footnote #ha3 ,except in the matter of low first cost cinders are not desirable for the drainage course4 ,in time1 this material is likely to slack1 or decompose1 and shrink in volume more or less and to allow the sidewalk to settle4 ,the hollow sound one often notices when walking over a sidewalk and the cracks that frequently appear1 are usually caused by the irregular settlement of the drainage course4 ,the object of wetting down the cinders several days before they are used is to cause as much as possible of this slacking to take place before the cinders are used in the drainage course4 ,footnote #hb3 ,there is a good deal of diversity of practice in the thickness of the concrete to be used4 ,for all ordinary sidewalks three inches of bottom course and one inch of surface-course are ample1 and in many cases the thickness of the surface course has been reduced to one-half inch with satisfactory results4 ,three-fourths inch of surface-course1 if fairly uniform in thickness and of good quality1 will generally be ample for ordinary sidewalks4 ,footnote #hc3 ,it is customary to make the surface-course concrete much richer than this1 but it is not necessary if the materials are good and the work well done4 ,footnote #hd3 ,this requirement is very important and should be strictly enforced1 otherwise there is danger that by the action of water1 frost1 and time1 the two courses may separate and the surface-course break up--a condition not infrequently observed4 ,footnote #he3 ,the troweling not only helps to secure a true surface1 but tends to produce a dense surface on the concrete2 but it is not desirable that this surface shall be smooth and glassy1 hence the slight roughening of the surface with a wire brush4 ,footnote #hf3 ,care must be taken to make and leave these expansion joints open to their full width entirely through the concrete4 ,the practice of forming these expansion joints by partitions of iron plate1 against which the blocks of sidewalk are built is not advised1 for the reason that they are likely to prevent the thorough compression of the concrete surface against or near the plates4 ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 ,silently corrected obvious typographical errors and variations in spelling4 #b4 ,retained archaic1 non-standard1 and uncertain spellings as printed4 #c4 ,re-indexed footnotes using numbers and collected together at the end of the last chapter4 #d4 ,enclosed italics font in underscores4 #e4 ,enclosed bold font in equals4 #f4 ,denoted subscripts by an underscore before a series of subscripted characters enclosed in curly braces1 e4g4 ,h#b,o4