THE IREIGATION AGE. 



181 



COUNTRY ROADS OF CONCRETE 



INEXPENSIVE IN FIRST COST AND 

 MAINTENANCE. 



No single factor plays such an important part 

 in the social and business life of a community as the 

 quality of its roads. Aside from the pleasure and 

 convenience of travel, possible at all times over 

 permanent roads, there is the financial 

 phase which directly concerns the cost 

 not only of farm produce but of city prod- 

 ucts as well. Consequently everybody 

 . wants good roads. In the matter of pay- 

 ing for permanent highways, a generally 

 satisfactory agreement seems to have 

 been reached in the proposed distribution 

 of the cost between the nation, the state, 

 the county and the users of the road in 

 question. As a result, within a few years 

 this country will take its rightful leading 

 position among the nations of the world 

 in the number of miles of permanent 

 roads. 



Changed Conditions Require Permanent 

 Material. 



In a way it is fortunate that the 

 United States has been rather slow in 

 the matter of road-making. The roads 

 can now be built of lasting materials such as 

 will withstand the wear of motor traffic, 

 which is fast ruining Europe's century-old 

 roadways. Lasting road materials are 

 everywhere present in the form of sand 

 and gravel from pits and stream beds and 

 crushed rock from stone quarries. Combined with 

 Portland cement into concrete, they form an inex- 

 pensive and permanent road surface which success- 

 fully resists the usually destructive action of auto- 

 mobiles. 



Inexpensive Local Materials Often Usable. 



The first consideration in the building of 

 crete roads is a careful study of local deposits of 

 sand, gravel and rock (called the aggregate) to see 

 whether they are suitable for concrete. Sand must 

 be clean and hard and must grade uniformly in size 

 of grain from j4-inch down. The same applies to 

 gravel and crushed rock except that the largest 

 particles commonly allowable are 1^4 inches in 



Repair-Proof Road of Concrete Always Usable. 



Dirt Roads and Worn-Out Macadam Often Impassable. 



diameter. If local materials are usable, a consider- 

 able saving will be effected, as only cement will 

 need be freighted. A brand of Portland cement 

 .-hould be chosen which is guaranteed to meet the 

 specifications of the United States Government or 



those of the American Society for Testing 



Materials. 



Mixing the Concrete and Building the 

 Road. 



It is much faster and cheaper to mix 

 the concrete with a machine than by 

 hand. Depending on the grading of the 

 aggregate, the concrete is usually propor- 

 tioned 1 bag of Portland cement to 2 cubic 

 feet of sand and 4 cubic feet of screened 

 gravel or crushed rock, or 1 of cement to 

 2 of sand and 3 of gravel or rock. During 

 the grading and draining of the road the 

 aggregate is hauled and piled at conven- 

 ient points. The concrete is mixed mushy 

 wet, is deposited to the thickness of 6 

 inches upon the firm old road-bed and is 

 brought to grade and shape by means of 

 a templet. In order to shed the water to 

 the side-drains the surface of the con- 

 crete is given a rise or crown in the cen- 

 ter of one one-hundredth (1/100) to one 

 seventy-fifth (1/75) the width of the road- 

 wav. The surface is finished with a 



