38 BULLETIN 407, U. S. DEPARTMENT OF AGRICULTURE. 
This pavement was completed in May, 1915. When inspected in 
December, 1915, it showed no evidence of failure or appreciable 
wear. The normal amount of traffic to which the road will be sub- 
jected is not yet developed, and another year will be required to test 
the wearing qualities of this pavement. 
EXPERIMENTS AT JUPITER, PALM BEACH COUNTY, FLA. 
OIL-ASPHALT-SAND. 
The purpose of this experiment was to demonstrate a simple and 
inexpensive method of treating the deep sand roads of Florida which 
are subjected to light traffic. The demonstration section is on West 
Lateral Road, 1.8 miles north of Jupiter, Fla. The bitumenized 
portion is 152 feet long and 9 feet wide, skirted on both sides by 
untreated sand shoulders 5^ feet wide. 
The mineral aggregate used was the native sand found in and along 
the roadway, in which was incorporated asphaltic materials, the prop- 
erties of which are given in Table 41. The sandbed was prepared 
for treatment by removing with hand rakes all twigs, sod, and similar 
undesirable matter from a width 10 feet on each side of the center 
line of the road. The sand in this area was then smoothed down to 
a uniform grade, while the cross section was shaped to a total crown 
of about 5 inches over the 20-foot width. 
The bituminous material was heated in 1-barrel kettles and was 
spread by means of hand-pouring pots in a series of applications, 
according to what is commonly known as the layer method. Four 
such applications were made. Each was covered with a layer of 
sand after the bituminous material had been partly absorbed. The 
sand for this purpose was obtained from the shoulders. Each layer 
of sand was thoroughly rolled with a 3-ton horse roller before the 
succeeding application of bitumen was made. The quantity of bitu- 
minous material and the thickness of the sand cushions in the various 
layers are stated below: 
(1) One-third gallon of bitumen A per square yard, over which 
was spread one-half inch of sand; (2) two-thirds gallon of bituminous 
material A per square yard which was covered with 1 inch of sand; (3) 
two-thirds gallon of bituminous material A per square yard, followed 
by a layer of 1 inch of sand; (4) one-third gallon of a combination of 
equal parts of A and B per square yard, to which was applied enough 
sand to absorb the bituminous material. 
The resulting cushion of bitumenized sand is approximately 3 
inches thick. The original plan involved the use of three layers only, 
but because of the damp condition of the sand on which the first 
application of oil was made, the hot asphalt foamed freely and the 
quantity poured was reduced by one-half. It was necessary, there- 
fore, to add another thin layer to give the desired depth. 
