18 BULLETIN" 586, U. S. DEPARTMENT OF AGRICULTURE. 
Table 18. — Analyses of asphalts. 
Experiment. 
Bitumi- 
nous gravel 
concrete. 
Clay 
asphalt. 
Specific gravity 25°/25° C 
Melting point °C 
Penetration at 25° C, 100 grams, 5 sec 
Loss, 5 hours, 163° C, 20 grants percent 
Penetration of residue, as above 
Per cent of total bitumen insoluble in 86° B naphtha 
Fixed carbon per cent 
Soluble in CS 2 (total bitumen) do. . 
Organic matter, insoluble do . . 
Inorganic matter, insoluble do. . 
Total do . . 
1.041 
54.5 
64 
.28 
42 
1.035 
55 
101 
.42 
57 
27.09 
18.88 
17.03 
99.45 
.16 
.39 
99.86 
.10 
.04 
100.00 
100.00 
Table 19. — Tests of bituminous concrete {plant samples). 
Sample 
having 
maximum 
bitumen. 
Sample 
having 
minimum 
bitumen. 
Sample 
having 
maximum 
coarse 
aggregate. 
Sample 
having 
minimum 
coarse 
aggregate. 
Average 
of 61 
samples. 
Per cent. 
8.5 
48.4 
38.5 
4.6 
Per cent. 
5.2 
59.0 
34.3 
1.5 
Per cent. 
5.4 
68.3 
23.3 
3.0 
Per cent. 
7.0 
34.1 
55.2 
3.7 
Per cent. 
6.5 
Aggregate retained on i-mch screen 
Passing \ inch screen and retained on 200- 
54.5 
35.8 
3.2 
Total 
100.0 
100.0 
100.0 
100.0 
100.0 
Table 20. — Tests of bituminous concrete (road samples). 
Sample 
having 
maximum 
bitumen. 
Sample 
having 
minimum 
bitumen. 
Sample 
having 
maximum 
coarse 
aggregate. 
Sample 
having 
minimnm 
coarse 
aggregate. 
Average 
of 42 
samples. 
Per cent. 
8.8 
52.9 
35.8 
2.5 
Per cent. 
4.0 
62.8 
31.3 
1.9 
Per cent. 
5.1 
66.8 
25.7 
2.4 
Per cent. 
8.5 
46.5 
41.6 
3.4 
Percent. 
6.4 
Aggregate retained on J-inch screen 
Passing i-mch screen and retained on 200- 
54.5 
36.1 
3.0 
Total 
100.0 
100.0 
100.0 
100.0 
100.0 
Table 21. — Mechanical analysis of earth. 
Per cent. 
Passing ^-inch screen, retained on 10-mesh sieve 0.4 
Passing 10-mesh sieve, retained on 20-mesh sieve 1.0 
Passing 20-mesh sieve, retained on 30-mesh sieve 2.0 
Passing 30-mesh sieve, retained on 40-mesh sieve 3.0 
Passing 40-mesh sieve, retained on 50-mesh sieve 3.0 
Passing 50-mesh sieve, retained on 80-mesh sieve 4.8 
Passing 80-mesh sieve, retained on 100-mesh sieve 2.2 
Passing 100-mesh sieve, retained on 200-mesh sieve 4.6 
Passing 200-mesh sieve 79. 
100.0 
