26 
BULLETIN 1077, U. S. DEPARTMENT OF AGRICULTURE. 
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 
DETAIL OF V SHAPED GUTTER 
C = CROWN OF PAVEMENT 
i! 
* / "Rad/us 
/'-8 
// 
. ' 7 : . • • • v 
. -. r : 
■ < • :"■ 
7 •. 
r; „ 
v j rods 3'- 6' 'long 2 L 6 Centers 
DETALU OF CURB 
t ... 
2 rods 3-6 long 
2'- 6' 'centers 
DETAIL OF CURVED GUTTER 
Fig. G. — 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 
