NA-3. 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: 



1. Specific gravity, 25°/25° C. (77°/77° F.) 1.050 to 1.070 physical and 



2. Flash point not less than 175° C. (347° F.) ^^l^l"''^ »'»»■ 



3. Melting point 40° C. (104° F.) to 50° C. (122° 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 3.0% 



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 95.0% 



6. Inorganic matter insoluble 1.5% to 3.0% 



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

 native asphalt shall be made in accordance with the following *"»• 

 tnethods : 



1. Speciflc gravity, U. S. Department of Agi'iculture 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 southern United States, 

 or for one size stone bituminous concrete in the northern United 

 States. It is intended to cover satisfactory grades of products 

 prepared by fluxing Bermudez asphalt. 



In bituminous macadam construction it should be applied in the 

 manner outlined iinder Speciflcation NA-2. 



One size stone bituminous concrete contemplates a mixture of 

 the fluxed asphalt with a crusher product passing a li-inch screen 

 and retained upon a one-half inch screen. The bituminous mate- 

 rial 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% to 7% 

 bitumen and will vary mthin these limits with the exact grading 

 of the aggregate. The hot mixture should be deposited in a uni- 



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