DUST PREVENTION AND ROAD PRESERVATION, 1915. 
39 
After the surface covering of sand was spread, the, shoulders and 
ditches were reshaped and the road was opened to traffic. A few 
days later the asphalt began to bleed freely, and the local road official 
in charge covered the road surface with a heavy additional layer of 
sand to absorb the exudation. 
The road was built on April 9 and 10, 1915, and was inspected 
December 10, 1915. The surface had received practically no atten- 
tion since the time of its completion. Along the center fine or crown 
of the 9-foot surface the horses had worn a path from 1 to 2 inches 
deep and about 14 inches wide, and two corresponding wheel ruts 
extended the full length of the section. The path and ruts are largely 
in a mass of loose sand, slightly impregnated with bituminous material 
from 1 to 1| inches deep which overlies a firm, hard course of bitu- 
minized sand. It is evident that the bituminous material used in 
the fourth layer was of too viscous a nature to assimilate the sand, 
or was insufficient in quantity to bind the heavy layer of sand which 
was spread to absorb the bleeding. Outside of the central traveled 
portion the surface is less broken. 
The surface requires reshaping and a light application of material 
A to bituminize the loose sand thoroughly. The road will then be 
scarred and rutted by traffic for several months, after which it should 
be reshaped with a grader occasionally until it is finally compacted. 
Table 41.— Analyses of bituminous materials used in experiment at Jupiter, Fla., 1915, 
Material. 
A. 
Residual 
asphaltic 
petroleum. 
B. 
Fluxed 
native 
asphalt. 
Specific gravity, 25°/25° C 
Melting point, ° C 
Viscosity, Engler, 50 CC. at 100° C. specific 
Float test at 50° C. (time) 
Penetration at 25° C 100 grams, 5 seconds 
Loss at 163° C. 5 hours, 20 grams, per cent 
Float test of residue at 50° C. (time) 
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), per cent. 
Organic matter insoluble, per cent 
Inorganic matter insoluble, per cent 
Total, per cent . 
1.01 
63.! 
2' 5' 
1.82 
3' 34" 
21.22 
12.61 
99. 
.12 
100. 00 
59 
5.43 
18 
23.61 
12.02 
95.48 
1.77 
2.75 
100.00 
COST DATA. 
This experiment was of too small extent for the cost data to be of 
material value. The asphalt was donated, and the total labor cost 
was only about $12.41, including the grading. This is at the rate of 
about 8.2 cents per square yard, exclusive of the bituminous material. 
