DUST PREVENTION AND ROAD PRESERVATION, 1914, 25 
Section No. 1 (REFINED WATER-GAS TaR PREPARATION). 
The first 100 feet of this section from the south end presented a 
markedly different appearance than the remainder, owing to the use 
on this portion of the section of bituminous materials of apparently 
different character for the 1914 treatment. The bituminous material 
used on this 100 feet was that remaining from the original treatment, 
and yielded a fine-grained, smooth appearance of a yellowish-gray 
color. The remainder of the section was treated with material 
obtained during the summer of 1914, and the treatment, which had 
at the time of inspection a reddish-brown color, had largely worn 
off in well-defined areas, showing the smooth mosaic surface of the 
original treatment. The section was smooth and had a true crown 
and uniform cross section. 
Section No. 2 (AspHattic PETROLEUM). 
This section, although it. had a good crown, had developed several 
small pot-holes, which were rapidly becoming deeper, and along 
the south edge toward the east end of the section the drainage from 
the embankment adjoining the road had evidently been instrumental 
“in causing deterioration of the surface mat. A surface treatment 
will be required the coming season. 
Section No. 3 (RESIDUAL PETROLEUM). 
The surface treatment applied on this section during the summer 
of 1914, like the previous treatment, has shown a tendency to become 
muddy in wet weather and to shove gradually toward the side of 
the road. At the time of inspection the mat in the traveled way 
was largely worn off. Several small pot-holes were scattered over 
the road, and adjoining the Thirteenth Street intersection and 
toward Twelfth Street there were several large worn depressions 
which would require extensive patching. In general the road had 
a smooth regular crown and a smooth mealy surface. 
Section No. 4 (AspHattic PETROLEUM). 
This section had a smooth, hard surface free from waves and an 
especially good crown. Along the middle of the road there was 
evidence of slight and uniform wear over large areas, and the under- 
lying macadam was beginning to show. 
SUPPLEMENTARY REPORT OF EXPERIMENTS AT CHEVY CHASE, MD. 
1912. 
BITUMINOUS CONCRETE, CEMENT CONCRETE, OIL-CEMENT CONCRETE, VITRIFIED 
BRICK, BITUMINOUS SURFACE TREATMENTS ON CONCRETE. 
The original report of these experiments was published in Cir- 
cular No. 99 of the Office of Public Roads and U.S. Department of 
Agriculture Bulletin No. 105. The following report covers the con- 
dition of the experiments when inspected on March 14, 1915. 
