20 BULLETIN" 246, U. S. DEPARTMENT OF AGRICULTURE. 



cents. These figures mean very little, unless the kiln is located con- 

 veniently near where the brick are to be used, for freight charges not 

 infrequently amount to more than the cost of the brick. 



A force consisting of one paver and five laborers should place on an 

 average about 220 square yards of brick per 10-hour day; while 

 supervision, rolling, and incidental expenses are ordinarily equivalent 

 to the cost of hiring about three and one-half additional laborers. 



If C = cost of cement per barrel, S = cost of sand per cubic yard, 



A = cost of coarse aggregate per cubic yard, B = cost of paving 



bricks per 1,000, and L = cost of labor per hour, with all materials 



considered delivered on the work and all costs expressed in cents, then 



the probable cost of constructing a brick pavement, including the 



subgrade, a 6-inch concrete foundation, and suitable curbs, may be 



estimated by substituting in the formula : 



i 



Cost per square yard = 1.90 L + .213 C + .138 S + .157 A + .040 B. 



The cost as estimated from this formula should usually be in- 

 creased by about 10 per cent to allow for wear on tools and machin- 

 ery and to guard against unforeseen contingencies. If it is desired 

 to use a different thickness of foundation, it is safe to assume that 

 each inch subtracted or added to the thickness of the foundation will 

 make a corresponding difference of from 8 to 12 cents in the cost per 

 square yard. 



MAINTENANCE OF BRICK PAVEMENTS. 



If brick pavements are properly constructed at the start, the work 

 of maintaining them is very slight. Under the closest inspection, 

 however, some inferior material is likely to become incorporated 

 either in the foundation or in the surface, and it is therefore very 

 important that a brick pavement be very carefully watched for the 

 first few years of its life to see that no unevenness develops either 

 because of defective brick having been used in the surface or because 

 of insufficient support from the foundation at any point. Whenever 

 any unevenness develops, it should be immediately rectified. Other- 

 wise the pavement will become irregularly worn in the vicinity of the 

 defects, and expensive repairs will eventually be necessary. 



Not infrequently weak spots develop in broken stone or gravel 

 foundations, owing to surface water finding its way through joints 

 in the pavement which have not been properly filled with grout. 

 Careful observation of the joints should therefore constitute a part 

 of the early maintenance work, and any defective joints discovered 

 should be immediately remedied. Where the foundation is con- 

 structed of concrete, however, slight defects in the joints seldom 

 result in anv very serious damage. 



