NA-8. FLUXED TRINIDAD 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. (7T°/77° F.) 1.200 to 1.250 jjgjjf al prop " 
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 50 to 60 
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 25 
6. Total bitumen (soluble in carbon disulphide), 
not less than 68.0% 
b. Inorganic matter insoluble 20.0% to 30.0% 
Tests of the physical and chemical properties of the fluxed Methods of test- 
native asphalt shall be made in accordance with the following ln s« 
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 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 for sheet 
asphalt construction in the northern United States. It is in- 
tended to cover satisfactory grades of products prepared by flux- 
ing Trinidad asphalt. 
Sheet asphalt construction contemplates a mixture of the fluxed 
asphalt with properly graded sand and a mineral filler. The 
asphalt and sand should be heated separately to a temperture of 
from 275° F. to 325° F. The filler should be added to the hot sand 
and followed by the asphalt. The mixture should contain from 
9 per cent to 12 per cent bitumen and will vary within these 
limits with the exact grading of the aggregate. After thorough 
mixing the hot mixture should be deposited in a uniform layer on 
a binder course which has been previously laid over a concrete 
base. It should be laid to such depth that it will yield a uniform 
layer 1| or 2 inches in thickness as may be required after thor- 
ough rolling. 
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