DUST PEEVEN-TION AND ROAD PRESERVATION, 1914. 31 



Section* No. 8 (Refined Water-Gas Tar Preparation — Surface Treatment). 



The surface presents a very uneven appearance, owing apparently 

 to the motion of the surface mat under traffic. A few small chuck 

 holes have formed where raveling seems imminent, although in general 

 the surface is very well bound. The section will probably require 

 some repair and a surface treatment during the coming spring. 



Section No. 9 (Asphaltic Petroleum — Surface Treatment). 



Toward the close of the season of 1914 this section began to give 

 evidence of considerable wear. As in previous seasons, deterioration 

 became more marked in the third of the road nearest the gutter and 

 was most evident over the south half of the section, where an ex- 

 ceedingly heavy rain had interrupted the progress of the previous 

 surface treatment. Two badly raveled places, each about half a 

 square yard in area, and a few smaller depressions were patched by 

 the penetration method with new lj-inch limestone and a heavy oil- 

 asphalt, rolled with a 10-ton roller, and finished by the application 

 of a seal coat of the same bituminous material. Several humps were 

 removed by cutting them flush with the surface by means of a mattock. 



Immediately after these repairs had been made, on October 17 and 

 19, a surface treatment was applied over the entire section, using the 

 same trade product as in the two previous treatments, and a fine 

 torpedo sand. The surface was first thoroughly swept with fiber 

 hand brooms, and the oil applied by allowing it to run from the bungs 

 of the barrels and distributing it with push brooms. The oil was 

 immediately covered with sand and the road opened to traffic. The 

 bituminous material cost 8 cents per gallon, and the sand cost $2.12 

 per cubic yard on the work. 



Table 22 gives an analysis of the bituminous material, and the cost 

 of surface treatment is given in Table 24. 



Table 22. — Analysis of asphaltic petroleum 1 used in surface treatment of section No. 9. 



Specific gravity, 25°/25° C . 0. 964 



Flash point °0. . 40 



Burning point °C 85 



Specific viscosity, Engler, 25° 0., 50c. c 113.3 



Loas, 5 hours at 103° C, 20 grams per cent. . 26. 46 



Floal test of residue 2 at 32° C. (time) 3' 46" 



Float test of residueatSO 0. (time) l'2i" 



p. i' 'i;ta','0 of total bitumen insoluble in 86° B. naphtha 7.43 



Fixed carbon per cent. . 5.04 



Soluble in c*, (total bitumen) do 99.92 



aic matter Insoluble do. . . . .06 



anic iii.ii ter Insoluble do 02 



Total do.... 100.00 



rly viscous, sticky fluid. J Very viscous, sticky fluid; glossy. 



