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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: Physical and 
„ , „ „ , „ chemical prop- 
1. Specific gravity 25°/25° C. (77°/77° 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 sec 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 : ing * 
1. Specific gravity, U. S. Department of Agriculture Bulletin 
314, p e 5. 
2. Flash point (open cup), U. S. Department of Agriculture 
Bulletin 314, p. 17. 
3. Melting point, A. S. T. M. Tentative Standard D-38-16 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, U. 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 lf-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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