NA-2. FLUXED BERMUDEZ ASPHALT FOR CONSTRUCTION. 



The fluxed native asphalt shall be homogeneous, free from GeneraL 

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

 It shall meet the following requirements : chemical prop- 



1. Specific gravity 25°/25° C. (77°/77° F.) 1.030 to 1.050 ertles. 



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



3. Melting point 40° C. (104° F.) to 50° C. (122° F.) 



4. Penetration at 25° C. (77° F.), 100 g., 5 sec 90 to 120 



5. Loss at 163° C. (325° F.), 5 hours not more than 3.0% 



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 95.0% 



&. Inorganic matter insoluble 1.5% to 2.5% 



Tests of the physical and chemical properties of the fluxed Methods of test- 

 ing, 

 native asphalt 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. 



Proc. 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 bituminous macadam in the middle belt of the United 

 States. It is intended to cover satisfactory grades of products 

 prepared by fluxing Bermudez asphalt. 



It should be applied at a temperature of from 300° F. to 350° F., 

 to the upper or wearing course of compacted broken stone at 

 the rate of from 11 to 1| gallons per square yard. The applica- 

 tion may be made by means of pouring pots or by a pressure dis- 

 tributor so designed that it will not produce ruts during appli- 

 cation. The above quantities are based on a wearing course 3 

 inches in thickness before rolling, composed of a product which 

 will at least pass a 3-inch laboratory screen and be retained on a 

 1-inch laboratory screen. The exact range in size should be 

 governed by the kind and quality of rock used. The application 



55478°— 18— Bull. 691 4 25 



