OA-4. OIL ASPHALT FOR CONSTRUCTION. 



The oil asphalt shall be homogeneous, free from water, xnd General, 

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

 It shall meet the following requirements: Physical and 



1. Specific gravity 25°/25° C. (77°/77° F.), chemical prop. 



^ erties. 

 not less than 1.010 



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 70 to 80 



5. Loss at 163° O. (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 45 



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 314, p. 17. 



3. Melting point, A. S. T. M. Tentative Standard D 36-16 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 Bulle- 



tin 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 con- 

 struction of one size stone bituminous concrete in the southern 

 United States or of graded coarse aggregate bituminous concrete 

 in the northern United States. It is intended to cover satisfac- 

 tory grades of oil asphalts prepared from Mexican, California, 

 Texas, and other petroleums. 



In one size stone bituminous concrete construction it should be 

 used in the manner outlined under Specification OA-3. 



Graded coarse aggregate bituminous concrete contemplates a 

 mixture of the oil asphalt with crushed stone or a mixture of 

 crushed stone and sand well graded in size from particles approxi- 

 mately one-half the thickness of the wearing course to dust. The 

 asphalt should be heated to a temperature of from 275° F., to 



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