OA-6. 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 



1. Specific gravity 25°/25° C. (77°/77° F.), Ss!''^ ^'"*" 



not less than 1.020 



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 50 to 60 



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 30 



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 Argiculture 



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 Bul- 



letin 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 fine aggregate bituminous concrete in the 

 southern United States or for sheet asphalt constructioii in the 

 northern United States. It may also be used as a seal coat on tar 

 macadam or tar concrete roads. It is intended to cover satisfac- 

 tory grades of oil asphalt prepared from Mexican, California, 

 Texas, and other petroleums. 



In fine aggregate bituminous concrete construction it should 

 be used in the manner outlined under specification OA-5. 



Sheet asphalt construction contemplates a mixture of the oil 

 asphalt with properly graded sand and a mineral filler. The 

 asphalt and sand should be heated separately to a temperature 

 of from 275° F. to 325° F. The filler should be added to the 



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