DRAINAGE METHODS' FOR COUNTY ROADS. 23 



after it is placed as can be clone witliout marring the surface, and keeping tlie 

 canvas wet constantly. After about 24 hours the canvas may be removed and 

 replaced with an earth covering about 2 inches thick. This earth covering 

 should be kept moist by periodic sprinkling during the two weeks it remains on 

 the pavement. 



BRICK GUTTERS. 



Brick glitters may be constructed, in a manner similar to that 

 described for cobble gutters, or they may be made as a part of the 

 road surface, as in the case of the second type of concrete gutter 

 described. They are used seldom on country roads except in con- 

 nection with brick pavements, and need not be especially discussed 

 here, as the method of constructing the gutters should not be essen- 

 tially different from that prescribed for the pavement. 



,n BRICK GUTTER 



Slopejjl' 



^r^^^/^/^---|L^R^^^^5^^J 



D=^ Cross-section is segment of a circle. 



Use vitrified brick. 



Sand bedding about 2" thick. 



Foundation of gravel or broken stone. 



Fig. 7. 

 COST OF GUTTERS. 



The cost of constructing gutters varies to a very great extent and 

 depends principally on the design of the gutter, the construction 

 methods employed, and the availability of materials. The amount 

 of work to be done may also, of course, have an important influence 

 on the unit cost, because this feature determines, in a great measure, 

 the manner in which a force of laborers should be organized for 

 carrying on the work. If the special conditions affecting any par- 

 ticular case are properly considered the following data should af- 

 ford a fairly reliable basis for preparing cost estimates for the three 

 types of gutters discussed above. 



First, consider a cobble gutter of the cross section shown in figure 4, the 

 foundation to be of crvished stone or gravel and the joints to be filled with 

 Portland-cement grout. 



Materials required for 100 linear feet : 



Foundation, 0.20 cubic yard crushed stone or gravel. 



Sand bedding, 0.07 cubic yard sand. 



Cobble paving, 0.15 to 0.20 cubic yard cobblestones. 



Grout, 05 to 0.08 barrel of cement, 0.20 to 0.30 cubic foot of sand. 



Second, consider a concrete gutter of the circular section shown in figure 5, 



