137 



All liars ralk'd Inr on the drawings arc- squaru and (if the lolldwing net sections; 



^" bars, net section 0.14 stiuare inch 



3/^" bars, net section 0.25 sciuare inch 



5^" bars, net section 0.39 square inch 



^1^ " bars, net section 0.56 square inch 



3^" bars, net section 0.77 square inch 



1 " bars, net section 1.00 square inch 



l 14" bars, net section 1.56 square inch 



All bars shall have a satisfactory mechanical bond appro\'ed by the Engineer. 



Round mechanical bond bars may be substituted, provided they ha\e the above net 



sections. Twisted steel bars will not be accepted as having a satisfactory bond. Where 



reinforcing steel is called for galvanized, it shall be uniformly covered with a spelter 



coating of two and one-half ounces of spelter per square foot of surface area. 



The contractor shall provide detail drawings showing his schedule for bending 



and splicing reinforcement. Three copies shall be submitted to the F.ngineer, one of 



which will lie returned to the Contractor after being approved. 



8. As phallic Coalitii!,. The asphalt used for the paint coat shall be homogeneous 



and free from water. The loss on heating, according to the method of the American 



Society of Testing Materials (Serial Designation I) 6-20), shall be not more than ^ 



per cent. After such healing the penetration of the residue shall be not less than 50 



per cent of the original sample. The penetration of the original sample shall tall 



between 90 and 110, using A. S. T. M methods for penetration (Serial Designation 



D 5-21). The softening point shall be lietween 100 and 90° F. using the hook and cube 



method. (A. S. T. M., D 61-20.) 



SECTION H 



Pkofortions 



1. Unit of i\Icasiiremenl. The unit of measure shall be the cubic foot. One sack of 

 Portland cement weighing ninety-four (94) poimds shall be considered as one cubic foot. 



2. Method of Measuring. Each of the constituent materials shall be measured 

 separately by \olume. The devices for measuring shall be sufficiently accurate to 

 insure a uniform mix and shall be subject to approval of the Engineer. The water 

 tank shall be so arranged that the water can be measured and regulated definitely and 

 the de\ice used shall be subject to approval by the Engineer. 



3. Proportions. The classification of concrete used in different parts of the struc- 

 ture will be designated by the proportions of cement to the total fine and coarse 

 aggregate. The quantity of water and the proportion of fine to coarse aggregate will 

 be determined by the Engineer from tests on the grading of aggregate and the re- 

 quirements of the construction. In general the quantity of water will be as small as 

 the tamping hereinafter specified will work into a homogeneous plastic mass. The 

 quantity of fine aggregate will be as small as will adequately fill the voids of the coarse 

 aggregate and will not exceed one-third of the total aggregate. The Contractor shall 

 measure and proportion the cement, water and aggregate in accordance with the 

 general classification designated in the plans and the detailed proportions determined 



by the Engineer. 



SECTION C 



M.\XIPUL.ATION 



1. Mi.xing. All concrete shall be mixed b\' machine of a type approved by the 

 Engineer. The arrangement of hoppers, water tank and measuring devices shall be 

 such that proportioning can be readih' controlled by the Engineer or his repr£S£mtative. 



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