42 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
WASHINGTON, D. C., 1915. 
BITUMINOUS CONCRETE. 
These experiments, constructed on the wing drives at either end of 
the main building of the United States Department of Agriculture, 
were described in Department Bulletin No. 407. At the time of 
inspection the surfaces were in excellent condition. They had had 
no repairs and required none. The only noticeable difference between 
the two experiments was the darker appearance and slightly closer 
texture of the surface constructed according to the District of Colum- 
bia specifications. 
BUENA VISTA, FLA., 1915. 
RESIDUAL ASPHALTIC PETROLEUM-CORALLINE ROCK. 
This experiment was intended to serve as a check on section 6 
of the Biscayne Drive experiments begun at Miami in 1913. The 
original report of the Buena Vista experiment appeared in Bulletin 
407, U. S. Department of Agriculture. The following report is 
based on an inspection made December 22, 1916. 
The traffic on this road has been very light and at the time of the 
inspection there was no evidence of wear on any portion. The 
surface showed some evidence of deterioration, however, from other 
causes. The following points were noted particularly: 
(1) Uneven bleeding, due either to lack of uniformity in the 
original distribution of the bituminous material or to segregation 
of the different-sized particles of the aggregate. As a consequence, 
the surface presented a mottled appearance, and where sand had 
been added to the ‘‘fat’”’ spots a surface mat had been formed, 
but because of the nature of the bituminous material this mat had 
not become bonded down firmly as a part of the road, but was 
easily loosened and scattered. 
(2) A trench had been excavated across the road to receive a 
pipe leading to a pump house on the side of the road. After the 
trench was backfilled the road surface was tamped back in place and 
treated with oil of the kind used in the original construction. The 
surface over the trench was about three-fourths of an inch high, 
but otherwise satisfactory. 
(3) About 50 feet of the south shoulder, near the pump house, 
was low and the surface showed a greater tendency to ravel here 
than on other portions of the road. ; 
JUPITER, PALM BEACH COUNTY, FLA., 1915. 
OIL-ASPHALT-SAND. 
The original report of this experiment appeared in Bulletin No. 
407, U.S. Department of Agriculture. The following report is based 
on an inspection made December 21, 1916. At that time the road 
