BRICK EOADS. 19 



nary cream and for the second application it should be somewhat 

 thicker. Mechanical mixers have also been satisfactorily used 

 for mixing and spreading the grout, and where the amount of work 

 to be done is sufficient to warrant such an initial outlay, they are 

 usually economical. 



The pavement should be cleaned and thoroughly sprinkled as a 

 preliminarj^ to making the first application of grout, and it should 

 be kept moist by gentle sprinkling while this application is being 

 made. The grout should be swept into the joints immediately after 

 it is removed from the boxes and spread upon the pavement. For 

 this purpose a coarse rattan or fiber push broom should be used in 

 "the first application and a squeegee in the second application. The 

 squeegee is usually made by clamping a piece of four-ply rubber 

 belting or some other similar material, about 6 by 20 inches in size, 

 between two pieces of board and attaching a suitable handle. The 

 grout in the boxes should be continually stirred until the last of it 

 is removed, otherwise a separation of the sand and cement will 

 almost certainly occur. 



The first application should proceed sufficiently far in advance 

 of the second for the grout of the first application to settle, but not 

 to take its initial set before the second application is made. Usually 

 both applications are made by the same crew of laborers. They 

 simply turn back after having covered the allowable distance with 

 the first application and, mixing the grout in the same boxes, bring 

 up the second application. The second application of grout should 

 completely fill the joints flush with the top of the brick. 



PROTECTING THE PAVEMENT. 



After the joints are filled as described above and the grout has 

 taken its initial set, the entire surface should be covered to a depth 

 of approximately 1 inch with sand or fine earth. This is done to 

 protect the pavement from the weather and to keep it in a moist 

 condition while the grout is hardening. If necessarj^, in order to 

 keep the covering moist, it should be occasionally sprinkled for 

 several days after it is spread. 



The covering should be permitted to remain on the surface for 

 at least 10 claj^s, and during this period the pavement should be kept 

 entirely closed to traffic. If the weather is unfavorable, the length 

 of time during which traffic is kept off the road should be increased. 



EXPANSION CUSHIONS. 



It has been customary in the past to provide both longitudinal and 

 transverse, bituminous expansion cushions in grout-filled brick pave- 

 ments, but recent practice has demonstrated that the transverse 



