DUST PREVENTION AND ROAD PRESERVATION, 1914. 25 



Section No. 1 (Refined Watee-Gas Tab 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 materia] 

 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 (Asphaltic 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 dram age from 

 the embankment adjoining the road had evidently been instrumental 

 in causing deterioration of the surface mat. A surface treatment 

 will be required the corning 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 (Asphaltic 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 largo 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 

 liltICK, I5ITUMINOUS SURFACE TREATMENTS ON CONCRETE. 



The original report, of these experiments was published in Cir- 

 eularNo. 99 of theOfficeof Public Roads and U. S. Department of 

 Agriculture Bulletin No. I0.">. The following report covers the con- 

 dition of the experiments when in ipected <>n March 14, 1915. 



