DUST PREVENTION AND ROAD PRESERVATION, 1915. 
41 
The cost of constructing this section was disproportionately high 
andean not bef airly compared with that of producing the other sections 
of the series. Neither is it a just criterion of the cost of building a 
sand-asphalt pavement. Hence the cost data are not given. 
Table 42. 
■Mechanical analyses of sands used in experiment No. 
Fla. 
West Palm Beach, 
No.l. 
No. 2. 
Mixed. 
Retained on 10-mesh sieve 
Per cent. 
0.0 
.3 
4.2 
23.9 
31.2 
36.9 
2.4 
1.0 
.1 
Per cent. 
0.1 
' .4 
1.2 
3.5 
5.2 
36.9 
21.5 
29.5 
1.6 
Per cent. 
1 
Retained on 20-mesh sieve 
.2 
Retained on 30-mesh sieve 
2.3 
Retained on 40-mesh sieve 
11.4 
16. i 
36.4 
15.4 
Retained on 200-mesh sieve 
17.2 
Passing 200-mesh sieve 
.6 
Total 
100.0 
100.0 
100.0 
COST DATA. 
This pavement was inspected in December, 1915. It had grown 
slightly wavy under traffic, but had not failed in any other respect. 
No difference in behavior or surface appearance was noticeable in 
the three subdivisions of the section. 
EXPERIMENTS AT OCALA, FLA. 
OIL-LIMESTONE, SAND-ASPHALT. 
Among the road materials locally available in Marion County are 
sand-clay, a fairly well-graded sand, and easily crumbled oolitic 
limestone, which hardens somewhat on exposure to the air. It is 
apparently similar in character to but much softer than the coralline 
rock used in the Miami and West Palm Beach experiments. In 
1915 an object-lesson road was constructed of sand-clay near Ocala, 
and on completion of this it was decided to construct experimental 
sections adjacent to the sand-clay road, utilizing the limestone and 
sand with bituminous materials. The series was installed in the 
spring of 1915 on the Ocala-Blichton road, about 3 J miles west of 
Ocala. Limestone for the oil-limestone experiment was obtained 
from a deposit which outcropped about 1 mile from the road. It 
was quarried with the use of dynamite and heavy sledges and in this 
way was easily broken to the desired size. For the surface course 
of the oil-limestone experiment the limestone was screened at the 
quarry over a ^-inch screen, yielding approximately 50 per cent 
retained on a J-inch screen and passing a 3-inch screen. A suitable 
quality of sand for the sand-asphalt experiment was located about 
two-fifths of a mile from the road. 
The equipment consisted of 2 sirup-heating kettles of 200 and 
80 gallons capacity, which were set in a stone furnace and heated 
