NA-4. FLUXED BERMUDEZ ASPHALT FOR CONSTRUCTION. 
The fluxed native asphalt shall be homogenous, free from water. General, 
and shall not foam when heated to 175° C. (347° F.) 
It shall meet the following requirements: Physical and 
' „ „ . „ chemical prop- 
1. Specific gravity 25°/25° C. (77°/77° F.) 1.050 to 1.070 erties. 
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 70 to 80 
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 35 
6. Total bitumen (soluble in carbon disulphide), 
not less than 95.0% 
&. 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 cut), U. S. Department of Agriculture 
Bulletin 314, p. 17. 
3. Melting point, A. S. T. M. Tentative Standard D36 16T., 
Proc. A. S. T. M. 1916, p. 549. 
4. Penetration, A. S. T. M. Standard Test D5-16. 
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 one size stone bituminous concrete in the southern 
United States or of graded coarse aggregate bituminous concrete 
in the northern United States. It is intended to cover satisfac- 
tory grades of products prepared by fluxing Bermudex asphalt. 
In one size stone bituminous concrete construction it should 
be used in the manner outlined under Specification NA-3. 
Graded coarse aggregate bituminous concrete contemplates a 
mixture of the fluxed asphalt with crushed stone or a mixture 
of crushed stone and sand, well graded in size, from particles 
approximately one-half the thickness of the wearing course to dust. 
The bituminous material should be heated to a temperature of 
from 275° F. to 325° F., and the mineral aggregate to a temper- 
ature of from 250° F. to 300° F. before mixing. The mixture 
should contain from 6 per cent to 8 per cent bitumen and will 
vary within these limits with the character of the rock and the 
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