DUST PREVENTION AND ROAD PRESERVATION, 1916, 
27 
Table 31.- 
-Contractor's 
cost 
of surface treating . 
experiments 
Mount Vernon experimental road, by 
Experiment No. 1. 
Experiment No. 2. 
Experiment No. 3. 
Item. 
Quantity. 
Cost. 
Cost 
per 
square 
yard. 
Quantity. 
Cost. 
Cost 
per 
square 
yard. 
Quantity. 
Cost. 
Cost 
per 
square 
yard. 
$28.00 
7.00 
52.80 
Cents. 
0.669 
.167 
1.261 
$39.20 
18.00 
108.00 
88.00 
65.20 
461.28 
183.37 
Cents. 
0.359 
.165 
.989 
.806 
.598 
4.226 
1.680 
$90.40 
20.00 
128.80 
Cents. 
2.159 
penses. 
Sweeping road 
Distributing 
oil or tar. 
4,187 square 
yards. 
2 ,048 gallons.. 
10,915 square 
yards. 
5 ,766 gallons.. 
5, 766 gallons.. 
139 cubic 
yards. 
/5,766 gallons,) 
\ at 8 cents. / 
139 cubic 
yards. 
4,187 square 
yards. 
3,557 gallons.. 
.478 
3.076 
Spreading 
gravel. 
Oil or tar 
Gravel 
54 cubic yards 
/2,048 gallons,) 
\ at 8i cents./ 
54 cubic yards 
14.00 
174.08 
71.23 
.334 
4.157 
1.701 
78 cubic yards 
(1,482 gallons, 
J at 8 J cents. 
12,075 gallons, 
I at 8i cents. 
78 cubic yards 
34.00 
125.97 
176.38 
102.90 
.812 
3.009 
4.212 
2.457 
Total... 
347.11 
8.289 
963.05 
8.823 
678. 45 
16. 203 
SUMMARY OF EXPERIMENTS ON GUM SPRING-MOUNT VERNON ROAD, FAIRFAX 
GOUNTY, VA. 
The following report describes the condition of the above experi- 
ments when inspected on January 11, 1917: 
Experiment No. 1. — Coal-Tar Preparation. 
The surface is breaking rapidly and becoming mealy, particularly 
up the grade at the beginning of the experiment. There is no well- 
formed mat; deterioration during the 10 days preceding inspection 
was noticeably rapid. 
Experiment No. 2. — Residual Asphaltic Petroleum. 
The surface has a very uniform mat for short distances, alternating 
with areas which have become badly rutted. The rutting has occurred 
both in cut and in fill, and in at least two places the red clay subgrade 
has worked through the gravel. 
Experiment No. 3. — Coal-Tar Preparation and Coal Tar Repined. 
This experiment shows a fairly intact surface, with a rather well- 
formed mat. It has only two or three small areas with any ruts 
whatever, and is not badly rutted anywhere. 
EXPERIMENTS WITH PIPE CULVERTS OF CORRUGATED METAL ON THE 
TEXAS POST ROAD IN COMAL AND HAYS COUNTIES, TEX. 
GALVANIZED AND UNGALVANIZED PIPE MADE OF VARIOUS KINDS OF IRON AND STEEL. 
These experiments are for the purpose of comparing the behavior 
of different kinds of iron and steel when used in corrugated pipe cul- 
verts under the conditions prevailing in Comal and Hays Counties, 
Tex. All of the culverts were placed in the spring and summer of 1 9 1 5 
and were in perfect condition when placed. They are reported on 
at this time in order to describe their condition when inspected in 
March, 1917. 
