BKICK ROADS, 13 



concrete composed of 1 part of Portland cement, 3 parts of sand, and 

 from 5 to 7 parts of broken stone or screened gravel. 



The sand should be clean and well graded in size, and the stone or 

 gravel should conform to the usual requirements for coarse aggregate 

 to be used in concrete construction. 



Brick pavements have in some cases been constructed with the sub- 

 grade as a foundation, and where the materials composing the 

 subgrade possess considerable supporting power under all weather 

 conditions to which the road is subjected, this method may prove 

 fairly satisfactory. Perhaps the most notable examples of brick roads 

 constructed in this way are to be found in the peninsular section of 

 Florida, where the soil is composed essentially of sand and where 

 there is no danger of upheaval due to frost action. At best, this 

 method of construction could hardly prove satisfactory for any ordi- 

 nary soil conditions above the thirty-fifth parallel of latitude, and even 

 below that latitude it should necessarily be confined to localities 

 where the soil is composed of sand, gravel, or some other material 



W 



^ftf-y I (li sand bedding. Joints filled with Portland cement gKout. 



6 



Slope 1:12. 



6 concrete foundation. c*- 



Crown ^ to I. 

 Slope of shoulders at least I tol2. 



Fig. 4. — Typical section for a brick road. 



which does not lose its stability when wet. Sand is the only material 

 of this kind which is at all widely distributed. The precautions most 

 necesary to observe in preparing sand foundations may be briefly 

 described as follows: 



(1) The road should be so graded and drained as absolutely to 

 prevent the foundation from becoming saturated with either storm or 

 ground water after the brick are laid. 



(2) The entire roadway should be thoroughly saturated with water 

 while it is being compacted, and a roller weighing not less than 10 

 tons should be used for compacting. Dry sand can not usually be 

 compacted by rolling. 



(3) Adequate stone or concrete curbs should always be provided. 

 At present wooden boards are being used in lieu of curbs for many 

 of the Florida roads, and in some cases this substitution can perhaps 

 be justified by the immediate necessity for improving a large mileage 

 of roads without suddenly increasing taxation to an unwarranted 

 burden. On the other hand it seems very doubtful if any community 



