DRAINAGE METHODS FOR COUNTY ROADS. 79 
cobbles shall be firmly bedded in the bedding sand and shall fit snugly, one 
against the other. They shall be set with their longest dimensions length- 
wise of the gutter and shall be so arranged as to break joints roughly. As the 
setting proceeds each cobble shall be rammed with a hand rammer weighing 
not less than about 20 to 30 pounds until it no longer yields under the rammer, 
and any irregularities that may be caused by ramming shall be corrected by 
taking up and resetting the affected portion. When the cobbles have been set 
and rammed as above described the gutter shall have the required cross section 
and shall present a uniform appearance. Where the gutter is to be grout filled 
care shall be exercised in setting and ramming the cobbles to see that the 
bedding sand is not forced up into the joints above the center of the cobbles. 
SAND FILLER. 
Where the plans provide for the joints of the cobble gutter to be filled with 
sand the sand used for this purpose shall conform to the specification for bed- 
ding sand and the filling of the joints shall proceed along with the setting and 
ramming of the cobbles. The sand shall be spread and swept over the surface 
of the gutter in sufficient quantity to leave a decided surplus on the surface 
after the joints have been completely filled. While the sand is being spread 
the entire surface of the gutter shall be repeatedly rammed so as to jar the 
sand thoroughly into the joints. After the joints are filled the gutter 
shall be true to the grade and cross section shown on the plans, and all of the 
cobbles contained in the paving shall be well bedded and so firmly held in 
place. 
GROUT FILLER. 
Where the plans provide for the joints of the cobble gutter to be filled with 
Portland-cement grout the grout used for this purpose shall be prepared by 
mixing together, by volume, 1 part of Portland cement, 2 parts of sand, and 
sufficient water to produce a consistency about equal to that of ordinary cream. 
The sand and cement shall first be thoroughly mixed dry, and the water shall 
then be admixed. After the grout is mixed it shall be kept constantly agitated 
until it has all been taken from the containing vessel and used in the joints. 
At the time the grout is applied the joints shall be entirely free from sand or 
other foreign material which extends above the center of the cobbles. The 
grout shall be repeatedly applied and swept back and forth over the surface 
of the gutter with a suitable broom or squeegee until the joints are filled 
flush and the surface of the gutter presents a smooth uniform appearance. 
After the grouting is completed as above described the gutter shall be pro- 
tected for at least two weeks until the grout hardens. In case drying weather 
prevails during this period the gutter shall be kept covered with earth or some 
other suitable material and shall be kept moist by occasional sprinkling with 
water. 
CONCRETE GUTTERS. 
Concrete gutters shall conform to the cross-section drawing shown on the 
plans for such gutters and shall be true in all respects to the line and grade 
as staked out by the engineer. 
Along the line of the gutter as staked out by the engineer a trench shall be 
excavated to the full width of the gutter, with allowance for necessary forms, 
and to such depth,, grade, and cross section that when the gutter is constructed, 
