DUST PREVENTION AND ROAD PRESERVATION, 1914. 23 
brittle, especially along the sides of the road, although the treatment 
still remained generally intact. Section No. 2 had developed several 
holes of considerable area, but otherwise the surface was in excellent 
condition. Section No. 3 had several small holes, and the surface 
mat was largely worn off. The surface of section No. 4 was smooth 
and regular, but the large stones of the macadam were generally 
showing. The only repair necessary in this section was a water-bound 
patch approximately 6 square yards in area on the northwest side of 
the curve leading toward Twelfth Street, where there is practically 
no traffic. 
In addition to this large patch, others of water-bound macadam 
were placed in sections 2 and 38. The total area of such patches was 
about 11 square yards. | 
The sections were then swept with hand brooms and given a sur- 
face treatment of the same type of bituminous material as that 
originally used, and covered with a fine torpedo sand. Some bitu- 
minous material had remained from the previous treatment, as fol- 
lows: 130 gallons of residual petroleum for section No. 3, which was 
sufficient to treat the entire section, and 50 gallons of water-gas tar 
preparation, which was used on the south end of section No. 1. 
Application of the bituminous material was accomplished by allow- 
ing it to run from the bungs of the barrels or drums directly upon the 
road and distributing it with push brooms. It was covered imme- 
diately with sand. 
Analyses of additional materials purchased for this work are given 
in the following tables: 
TABLE 15.— Mechanical analysis of sand used in surface treatment at Washington, D. C., 
1914. 
iermedvon.t-mchisereen! 24. ss2 0125.2. ood Jo aie ene see sae per cent.. 11.8 
Passing $-inch' screen, retained on 10-mesh sieve...:......2---2-.------ dort 1687 
Passing 10-mesh sieve, retained on 20-mesh sieve...........-------22--- Co Koynsgoenner 41 7/80) 
Passing 20-mesh sieve, retained on 30-mesh sieve........./.---.-.--..- dons ON 
Passing 30-mesh sieve, retained on 40-mesh sieve.........-..---------- Chases LD 
Passing 40-mesh sieve, retained on 50-mesh sieve.....-.....----------- dons e.9 1029 
Passing 50-mesh sieve, retained on 80-mesh sieve...........2...-...... CO. 245 Ay 
Passing 80-mesh sieve, retained on 100-mesh sieve..........----------- dO ve Sey 
Passing 100-mesh sieve, retained on 200-mesh sieve........-..--- sae areas COPS 
Pacsmes200-mesh sieves Aske Ul aera Ue OA Ao: Asa aa ee» dOnt or3 
Matas ee ese tess ise eae tese cere aera: CU Poet eae do. 100. 0 
Tape 16.—Analysis of water-gas tar preparation used on section No. 1. 
Nweciuertaviingoo alo, Oinere series. ee Sea levi cede eae OSL 1. 091 
NaRcosttiy, wh nolers LODE NC. atio0r C2 specie 045 2 ahve fe 2\ Jo dsl cee Bae wel 18.4 
cere ah Ollerre eae eee er dis cee nie eee gy Ee, UL eo per cent: 2) - 2: 22 
