OA-5. OIL ASPHALT FOR CONSTRUCTION, 



The oil asphalt shall be homogeneous, free from water, and shall General. 

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

 It shall meet the following requirements: Physical and 



1. Specific gravity 25V25° C. (77V77° F.)-not less than 1.010 ert^sf*^ ^'°^" 



2. Flash point not less than 175° O. (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 60 to 70 



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 40 



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 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 con- 

 struction of graded coarse aggregate bituminous concrete in the 

 southern United States or for graded fine aggregate bituminous 

 concrete in the northern United States. It Is intended to cover 

 satisfactory grades of oil asphalts prepared from Mexican, Cali- 

 fornia, Texas, and other petroleums. 



In graded coarse aggregate bituminous concrete construction it 

 should be used in the manner outlined under Specification OA-4. 



Graded fine aggregate bituminous concrete contemplates a mix- 

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

 stone and sand well graded in size from particles that will pass a 

 one-half-inch laboratory screen to dust such as the " Topeka " type 

 of pavement with its modifications. The asphalt should be heated 



55478°— 18— Bull. 691 3 17 



