26 



BTJLLETIiSr 10*77, U. S. DEPARTMEISTT OF AGEICULTURE. 



surface treatment. The thickness of the coating is generally from 

 one-fourth to three-eighths inch. Bituminous surface treatments 

 have been used to some extent, principally because it was thought 

 that they served to protect the concrete pavement by cushioning the 



2-6 cenhers 



DETAIL OF V SHAPED GUTTER 



C = CROWN OF PAVEMENT 



^ / "Pad/ as 



1-8 



2 rods J" 6 "lon^ 2-6 Centers 



DETAIL OF CURB 



■•T.-'v-'-: 



2 rods 3-6 lon^ 

 2'~ 6" centers 



DETAIL OF CURVED GUTTER 



Fig. 6. — Typical details of gutter and curb. 



impact of traffic and preventing the abrasion of the surface. Their 

 use is now being generally discontinued. It is found that a bitu- 

 minous surface approximately one-fourth inch thick has little, if 

 any, cushioning value and consequently does not lessen the impact 



