36 BULLETIN Wl, U. S. DEPARTMENT OF AGRICULTURE. 
States Department of Agriculture, located about 3 miles north of 
Miami. The roadway is 1,725 feet long and is 12 feet and 16 feet in 
width. The traffic to which it is subjected is light, and originates on 
the grounds of the experimental gardens. 
The site is a new location, which was cleared, grubbed, and graded 
immediately before the surfacing was undertaken. After leaving the 
Miami-Lemon City Road, the first 600 feet was a deep sand bed, 
while the remainder was a succession of ridges of coralline rock, with 
sand beds intervening. The coralline ridges were excavated, and a 
uniform sand subgrade was prepared. 
The surfacing materials used were coralline rock and a heavy 
asphaltic oil. The properties of the rock as it occurs near Miami are 
noted in U. S. Department of Agriculture Bulletin No. 105. The sub- 
grade, which was 6 inches thick, loose, was built of coralline fieldstone 
gathered on or near the site of the project, sledged on the subgrade 
and thoroughly rolled. 
The rock for the wearing course was taken from a county pit about 
1 mile from the road. The fine material resulting from blasting was 
eliminated by screening the rock over one-fourth inch stationary 
screens. The wearing course was 3 inches thick, loose, and was rolled 
once over with an 8-ton macadam roller before the bituminous ma- 
terial was applied. The cross section of the road shows a crown 
slightly less than one-half inch per foot. 
The properties of the bituminous material are stated in Table 39. 
This material was delivered in barrels, heated in 1-barrel kettles, 
and applied by means of hand-pouring pots. From 1 to 3 hours 
after it had been poured the bituminous material was covered with 
about one-half inch of sand which had been taken from the roadside 
and screened to remove twigs, roots, etc. The sanded surface was 
then rolled until all visible movement of the surface particles ceased, 
after which the road was opened to traffic. 
The cost of the various processes involved in the construction of 
this section are given in Table 40. The cost data are based on labor 
and material as follows : 
Superintendent, per day $4. 00 
Foreman, per day 3. 00 
Teams, per day 5. 00 
Labor, per day 1-50 
Roller, per day 6. 00 
Bitumen, per gallon 134 
