20 
BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
Table 24 — Summary of material and labor costs. 
Item. 
Quantity in working unit. 
Total cost. 
Cost 
per work 
unit. 
Foundation: 
39,377.4 square yards 
S7.50 
2,244.28 
Cents. 
0.019 
5.699 
Total 
5.718 
50,160 linear feet 
125.00 
3, 168. 05 
Shoulders: 
.25 
6.31 
Total 
6.56 
38,442.6 square yards 
7,095.40 
11,970.31 
Surface: 
18.45 
Labor 
31.13 
Total 
49.58 
223.75 
429. 56 
Surface: 
23.92 
45.95 
Total 
69.87 
7,000.00 
1,230.10 
33,493.95 
The above cost data are based on the following unit prices of 
labor : 
Foremen per day of 8 hours.. S4. 00 
Rollermen and skilled laborers do 4. 00 
Laborers per day. . 1. 60-2. 40 
Trucks per hour . . 1. 00 
Teams per day. . 4. 50 
SUMMARY OF EXPERIMENTS ON ALEXANDRIA-ACCOTINK ROAD. 
The following describes the condition of the above experiments 
when inspected on January 11, 1917. 
Experiment No. 1. — Bituminous Gravel Concrete. 
The surface of this experiment is practically in perfect condition. 
Difficulty has been found already with the rutting of the right-hand 
shoulder going down steep grades, but at the time of inspection there 
was no indication that the edge of the surfacing had begun to shear. 
Experiment No. 2. — Earth Oil Asphalt. 
This section never had an opportunity to dry out thoroughly, since 
freezing weather came on the day following its completion. During 
thaws it was kept in shape for some time with a road grader and small 
tandem roller, but at the time of inspection was rather badly rutted 
and broken through to the gravel foundation in two places. 
EXPERIMENTS ON THE GUM SPRING-MOUNT VERNON ROAD, FAIRFAX 
COUNTY, VA. 
BITUMINOUS SURFACE TREATMENT ON A NEW GRAVEL ROAD. 
The Mount Vernon Road extends from Gum Spring, in a southerly 
direction, 2.05 miles to the Mount Vernon estate, and is wholly in 
