64 
BULLETIN 407, U. S. DEPARTMENT OF AGRICULTURE. 
the half along the gutter was muddy and showed a tendency to 
disintegrate. A line of potholes existed along the middle. Much 
patching will be required as soon as weather permits. In a few 
places the road metal is raveling and the winter calks on the horses' 
shoes have cut entirely through the mat on the east side of the road. 
It appears from a few breaks just forming at the time of inspection 
that it is this cutting of the mat which starts the numerous pot- 
holes. The cost of this re-treatment is shown in Table 64. 
Table 64. — Materials and cost data for surface re-treatments. 
| 
Quantity of 
material per 
Cost per square yard (cents). 
Bituminous material. 
to 
is 
square yard. 
6 
3 
2^, 
3 "ST 
03 
a 
CO 
3 — 
oi 
J 
u 
a 
03 • 
to -s 
g 
fc 
3 , 
-■= 
OT3 
a -3 
to 
60 is 
2 
.2 
03 
<D 
III 
03 
03 
PI 
03 
i 
03 
"'Ha 
£60 
t 
ft 
"3 
m 
< 
cq 
C5 
CO 
pq 
O 
m 
o 
<! 
<l 
02 
Eh 
9 
Asphaltic petroleum, cold 
761 
1,013 
0.197 
.172 
(') 
0) 
0.016 
.016 
2.6 
2.4 
I 1 ) 
C 1 ) 
3.6 
3.6 
0.1 
.2 
0.4 
.6 
0.4 
.5 
0.4 
.5 
7.5 
in 
do 
7.8 
i Not ascertained. 
MAINTENANCE DURING 1915. 
In addition to the general re-treatments above described, the patrol 
system of maintenance was continued during the year. Table 65 
presents the total cost of this maintenance and the re-treatments, 
together with the total cost of each experiment to December 31, 1915. 
Table 65. — Costs of construction and of surface mainteannce to December 81, 1915, of 
1911 experiments at Chevy Chase, Md. 
Experiment No. 
Date 
com- 
pleted. 
l: 
1911. 
Oct. 31 
2 
...do 
3 
Nov. 18 
4 
Nov. 8 
5 
Dec. 2 
6 
Nov. 23 
7a 
Dec. 5 
7b 
...do 
8 
1912. 
Aug. 24 
9 
10 
Nov. 22 
11 
Dec. 16 
Area. 
Sq. 
1,581 
705 
1,555 
1,555 
1,447 
1,555 
131 
848 
1,477 
761 
1,013 
377 
Maintenance cost of experiment. 
To 1913, 
SO. 00 
.00 
.00 
4.05 
262. 57 
3.47 
1.43 
67.88 
80.64 
39.65 
19.05 
.00 
19141 
S91.48 
.00 
.00 
2.54 
.90 
.00 
.45 
1.33 
.00 
44.86 
286. 62 
.00 
1915 
S36. 97 
16.14 
14.71 
40.18 
42.03 
32.15 
4.70 
24.50 
50.16 
63.71 
132. 17 
.00 
Total. 
S128. 45 
16.14 
14.71 
46.77 
305. 50 
35.62 
6.58 
93.71 
130. 80 
148. 22 
437.84 
.00 
Construction per square 
yard (cents). 
Con- 
struc- 
tion. 
46.18 
64.42 
64.69 
57.18 
58.27 
68.22 
59.96 
54.80 
2 39. 59 
42.01 
44.31 
81.51 
Mainte- 
nance. 
8.12 
2.29 
.95 
3.00 
21.11 
2.29 
5.02 
11.05 
8.86 
19.48 
43.22 
.00 
Total. 
54.30 
66.71 
65.64 
60.18 
79.38 
70.51 
64.98 
65.85 
48.45 
61.49 
87.53 
81.51 
i Differences between these quantities and those appearing in Table 25, page 34, U. S. Dept. Agr. Bul- 
letin 257, are due to a distribution of "General expenses," not made in the earlier table. 
2 The construction costs here shown for sections 8, 9, and 10 are uniformly 32.58 cents higher than those 
appearing in the original table of costs on page 9 of Circular No. 99. The amount represents the cost of the 
2-inch top course of water-bound macadam, and it is added here in order to make the costs of the wearing 
courses of these sections comparable with the costs of penetration and mixed surfaces on other sections. 
