NA-5. 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: Physical and 



1. Specific gravity 25°/25° C. (77°/77° F.) 1.050 to 1.070 erti"'!''' ^''"''' 



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



3. Melting point 45° C. (113° F.) to 55° C. (131° 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 3.0% 



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 94.5%. 



b. Inorganic matter insoluble 2.0% to 3.5% 



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. IMelting 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 graded coarse aggregate bituminous concrete in the 

 southern United States or of graded fine aggregate bituminous con- 

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

 factory grades of products prepared by fluxing Bermudez asphalt. 



In graded coarse aggregate bituminous concrete construction it 

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



Graded fine aggregate bituminous concrete contemplates a mix- 

 ture of the fiuxed 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 bitumi- 

 nous material should be heated to a temperature of from 275° F. 

 to 325° F. and the mineral aggregate to a temperature of from 



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