DUST PREVENTION AND ROAD PRESERVATION, 1914. 



33 



still remaining. The oil was almost immediately covered with gravel, 

 and finally the entire section was rolled lightly with an 8-ton tandem 

 roller. After several days' traffic a subsequent light application 

 of sand was found necessary to absorb the bituminous material that 

 came to the surface. The material and cost data for the surface 

 treatment is given in Table 24. 



At the time of inspection the section had passed through a long 

 spell of unfavorable weather, and its appearance demonstrated that 

 the treatment was applied too late in the season. Numerous small 

 but deep cup-holes had formed, extending into the water-bound 

 macadam, and in general the entire surface had become very muddy. 

 Considerable patching will be necessary at an early date. 



Section No. 11 (Native Asphalt Emulsion — Macadam Resurfacing). 



The section has had no treatment since it was resurfaced, and dur-* 

 ing the past year it has worn very uniformly, so that at the time of 

 inspection the large stones were generally exposed over the entire 

 surface. There are a few long waves and in a few places the large 

 stones have apparently broken under traffic, but otherwise the surface 

 is in excellent condition. 



MAINTENANCE DURING THE YEAR 1914. 



In addition to the general re-treatment above described, the patrol 

 system of maintenance was continued during the year. Table 25 

 presents the total cost of this maintenance and the re-treatments, 

 together with the total cost of each experiment to December 31, 1914. 



A traffic census is taken every 13 days for a 24-hour period. A 

 tabulation of the maximum and average of each class of traffic for 

 the period between March 1, 1914, and March 1, 1915, is given in 

 Table 20. The east side of the road carries outgoing traffic and the 

 west side incoming traffic. 



Table 24. — Materials and cost data for surface treatment in 1914 of sections 1, 9, and 10 ! 

 at Chevy Chase, Md., 1911 project. 





Bituminous mate- 

 rial. 



1 



3 



.3 '■ 

 || 



*o 



2 



E 



-; 



Quantity or mate- 

 rial per square 

 yard. 



Cost por square yard (cents) . 



Sec- 

 tion 



No. 



9 3L 



2 - £ 



.3 ^ c 



3 



3 . 



gi 



o 



3 



3^ 



v. 



o a 



3 53 

 5 3 



« 



o 

 3 



3 

 ^T"3 



E 







3 



3 • 



_■ «3 

 I 



0Q 



f! 



CD 



5 



3 s . 

 Si a 



ass 

 < 



P.CJ « 



P.CO&J 



.9 

 a 



o 



"3 



O 





1,681 



761 



1,013 



0.316 



0.007 



.0020 



2. 0HK 



1 . 672 

 :i. 807 



1 . 688 

 2. 828 







10.701 

 .436 

 .648 



0. 625 





5.042 



9 



/'■ petroleum 



do 



. ■» ft 



.011 



1.811 



. 1 1 ■ < 



6. 366 

 ,889 



. 134 

 .671 



6 009 



i 709 

 8. ill 



■ [nchidi .. co it oi Bweeplng. 



