VITRIFIED BRICK AS MATERIAL FOR COUNTRY ROADS. 15 
TRUING THE SURFACE. 
After the pavement has been laid and all defective brick have been 
replaced to the satisfaction of the engineer, the next step is to sweep 
the surface clean and smooth out all inequalities by means of ramming 
or rolling. The rolling should be done with a power roller weighing 
from 3 to 5 tons, and the pavement should ordinarily be rolled in both 
the longitudinal and transverse directions. The longitudinal rolling 
should be done first and should begin at the curbs and progress toward 
the crown. The roller should pass at least twice over every part of 
the pavement in both transverse and longitudinal directions. In 
order to neutralize any tendency which the brick may have to careen 
under the roller, the number of forward trips over any part of the pave- 
ment, if more than two trips are required, should equal the number of 
trips backward over the same part. 
In places where it is impracticable to use the roller for truing the 
surface, such, for example, as along the curbs or concrete gutters 
or around manholes, the brick should be brought to a true surface by 
means of ramming. For this purpose a wooden rammer loaded with 
lead and weighing from SO to 100 pounds may be used. The blows of 
the rammer should not fall directly upon the brick, but should be 
transmitted through a 2-inch board laid parallel to the curb. 
After the pavement has been trued up, as described above, it should 
be inspected again for broken or otherwise damaged brick, and also 
for those which have settled excessively, owing to some lack of uni- 
formity in the sand cushion. All defects should be corrected and the 
areas distributed in making the corrections should be brought to a 
true surface by tamping. 
FILLING THE JOINTS. 
In order to keep the brick in proper position and protect the edges 
from chipping, it is necessary to fill the joints with some suitable mate- 
rial before the road is opened to traffic. The materials which have 
in the past been most commonly used for this purpose are sand, va- 
rious bituminous preparations, and a grout made of equal parts of 
Portland cement and fine sand mixed with water. 
Sand is the least expensive of these materials, but there are several 
very serious objections to its use as a joint filler: (1) It does not pro- 
tect the edges of the brick; (2) it is easily disturbed in cleaning the 
pavement and is likely to be washed out by ram on steep grades; (3) 
it does not entirely prevent water from penetrating through to the 
foundation; and (4) it does not bond the individual brick together, 
and so enable them to present a concerted resistance to traffic. 
The bituminous fillers vary considerably in quality and efficiency, 
but all are more or less unsatisfactory. One of the principal objec- 
tions to their use is based on their tendency to run out of the joints 
into the gutters during warm weather and to crack and spall out 
