DUST PEEVENTIO]Sr AND EOAD PEESERVATION, 1915. 57 



At the time of the inspection made on February 25, 1916, the con- 

 dition was substantially as follows : 



Section 1, which was not re-treated during the past season, appeared 

 in no need of re-treatment. 



Section 2 had become rough and uneven, owmg both to settlement 

 imder traflEic in extremely wet weather and to disintegration of the 

 surface. One large hole had developed on the south side at a point 

 where traffic entering from Fourteenth Street fads to turn closely 

 enough to the north corner and in consequence shears away the south 

 edge for several feet. This section has also a number of potholes and 

 spots where the mat was entirely worn away. Extensive repairs will 

 be necessary as soon as the weather permits. 



Section 3 suffered as usual on account of seepage from the terrace 

 that hes along the south side of the section. An effort was made to 

 drain this section and a small part of section 2, but suflElcient funds 

 were not available to complete the work. 



Section 4 has remained in excellent condition. Only one small 

 area at the south end has required any attention. The break at this 

 point was due to the impact of traffic passing from the asphalt drive- 

 way tc the surface treatment. 



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 begun in Circular No. 

 99 of the Office of Public Roads and completed in U. S. Department 

 of Agriculture Bulletin No. 105. Report of inspection made on 

 March 14, 1915, was published in Department Bulletin No. 257. The 

 following report covers the condition of experiments on February 

 28, 1916. 



Experiment No. 1. — Bituminous Concrete, Topeka Specification. 



The general appearance of the experiment is the same as at the last 

 inspection. Imperfections then noted still exist in addition to those 

 noted here. There is one bad break at the north side of the turn into 

 Bradley Lane. Both surface and concrete gutter are broken and 

 indicate some unusual blow. The depression noticed about midway of 

 the section near the curb has increased in size and depth. A second 

 cup-hole 200 feet north of Bradley Lane, near the east side of the 

 road, and a third one, 60 feet from the north end of the limestone 

 section, were noted. In the last 60 feet of this section, 10 or 12 slight 

 imperfections appear. On the trap section a noticeably increasing 

 waviness occurs along the gutter for a width of 2 to 2^ feet. 



