OA-3. OIL ASPHALT FOR CONSTRUCTION. 



The oil asphalt shall be homogeneous, free from water, and GeneraL 

 shall not foam when heated to 175° C. (347° F.). 

 It shall meet the following requirements: diemfcai'^^prov)* 



1. Specific gravity 25V25° C. (77V77° F.)_not less than 1.010 erties. 



2. Flash point not less than 175° C. (347° F.) 



3. Melting point 40° C. (104° F.) to 60° C. (140° F.) 



4. Penetration at 25° C. (77° F.), 100 g., 5 see 80 to 90 



5. Loss at 163° C. (325° F.) 5 hours not more than 1.0% 



a. Penetration of residue at 25° C. (77° F.). 100 g., 

 5 sec not less than 50 



6. Total bitumen (soluble in carbon disulphide), 



not less than 99.5% 

 a. Organic matter insoluble not more than 0.2% 



Note. — Material for any one contract shall not vary more than 0.020 

 in specific gravity nor more than 10° C. in melting point within the test 

 limits above specified. 



Tests of the physical and chemical properties of the oil asphalt Methods of test- 

 shall be made in accordance with the following methods : "^' 



1. Specific gravity, U. S. Department of Agriculture Bulletin 



314, p. 5. 



2. Flash point (open cup), U. S. Department of Agriculture 



Bulletin 814, p. 17. 



3. Melting point, A. S. T. M. Tentative Standard D-8d-16 T, 



Proceedings A. S. T. M. 1916, p. 549. 



4. Penetration, A. S. T. M. Standard Test D 5-16. 



5. Volatilization test, U. S. Department of Agriculture Bulletin 



314, p. 19, using 50 gram sample, 



6. Total bitumen, XJ. S. Department of Agriculture Bulletin 



314, p. 25. 



This specification provides for a material to be used in the 

 construction of bituminous macadam in the southern United 

 States or for one size stone bituminous concrete in the northern 

 United States. It is intended to cover satisfactory grades of oil 

 asphalts prepared from Mexican, California, Texas, and other 

 petroleums. 



In bituminous macadam construction it should be applied in 

 the manner outlined under Specification OA-2. 



One size stone bituminous concrete contemplates a mixture of 

 the asphalt with a crusher product passing a l|-inch screen and 

 retained upon a half-inch screen. The asphalt should be heated 

 to a temperature of from 275° F. to 325° F. and the crushed stone 

 to a temperature of from 150° F. to 250° F. before mixing. The 

 mixture should contain from 5 per cent to 7 per cent bitumen. 

 The hot mixture should be deposited in a uniform layer over a 



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