DUST PREVENTION AND ROAD PRESERVATION, 1916. 61 
Table 65. — Materials and cost data for surface re-treatment, Chevy Chase, Md., in 1016. 
Item. 
Experi- 
ment No. 
8, refined 
water-gas 
tar prep- 
aration. 
Experi- 
ment No. 
9 ? asphal- 
tic petro- 
leum. 
Experi- 
ment No. 
10, asphal- 
tic petro- 
leum. 
square yards . . 
1,477 
•0. 149 
761 
0.289 
.0138 
1,013 
Quantity of material per square yard: 
Bituminous material 
gallons.. 
cubic vards. . 
0.299 
.0114 
Sand 
do 
.0115 
Cost per square yard (cents): 
1.85 
3.47 
3.53 
3.59 
2.91 
Sand 
2.95 
.13 
.41 
.55 
.25 
.41 
.03 
.54 
.19 
.26 
.74 
.30 
.49 
.23 
.36 
1.02 
Total 
6.55 
8.76 
8.93 
Table 66. — Surface maintenance costs of 1911 experiments at Chevy Chase, Md. 
December SI, 1916. 
to 
Area. 
Maintenance cost of experiments. 
Total cost per square yard. 
Experiment No. 
Total for 
experi- 
ments to 
Dec. 31, 
1915. 
1916 
Total. 
Con- 
struction. 
Main- 
tenance. 
Total. 
1 
Sq. yds. 
1,581 
705 
1,555 
1,555 
1,447 
1,555 
131 
848 
1,477 
761 
1,013 
377 
$128.45 
16.14 
14.71 
46.77 
305. 50 
35.62 
6.58 
93.71 
130. 80 
148. 22 
437.84 
0.00 
$4.23 
4.55 
5.92 
10.32 
7.75 
8.85 
J 2.90 
117.05 
77.97 
131. 16 
5.88 
$132. 68 
20.69 
20.63 
57.09 
313. 25 
44.47 
103. 19 
247. 85 
226. 19 
569. 00 
5.88 
Cents. 
46.18 
64.42 
64.69 
57.18 
58.27 
68.22 
f 59.96 
\ 54.80 
39.59 
42.01 
44.31 
81.51 
Cents. 
8.39 
2.93 
1.33 
3.67 
21.65 
2.86 
} 10.54 
16.78 
29.72 
56.17 
1.56 
Cents. 
54.57 
2 
67.35 
3 
66.02 
4 
60.85 
79.92 
6 
71.08 
7a 
7b 
66.03 
8 
56.38 
9 
71.73 
10 
100.48 
11 
83.07 
Section No 11 — Native asphalt emulsion, macadam surfacing. — 
This section never has been re-treated and it has required no patching 
until the past season, when a few slight breaks were repaired. The 
mat was breaking rapidly and at date of inspection there were 
numerous places where the aggregate was exposed and four or five 
places where raveling was imminent, with moisture coming through 
about 60 per cent of the surface. It was probable that considerable 
patching and a reseal would be required in the spring. 
Maintenance during 1916 — In addition to the general re-treatments, 
as above described, the patrol system of maintenance was continued 
during the year. Table 66 presents the total cost of all maintenance, 
including the re-treatments shown in Table 65 
