PORTLAND CEMENT CONCRETE PAVEMENTS. 27 



Dimensions of pavements, length of haul for materials, and cost of cement and 

 amount used per square yard. 



Project No. 1 : 



Area of pavement laid : square yards — 5,000 



Thickness of pavement inches — 6 



Width of pavement feet — 45 



Length of haul for materials mile — I 



Cost of cement per barrel dollars — 1. 0G 



Amount of cement used per square yard barrel— . 29 



This is a one-course pavement for which the coarse aggregate was gravel 

 mixed with a small amount of Joliet crushed stone. The conditions under 

 which the pavement was constructed appear to have been favorable. The cost 

 is low. 



Project No. 2 : 



Area of pavement laid square yards 7,111 



Thickness of pavement inches 6 2 



Width of pavement feet — 16 



Length of haul for materials miles — 1 2 



Cost of cement per barrel dollar . 98 



Amount of cement used per square yard barrel— . 33 



This is a one-course pavement. The sand and crushed stone were both 

 obtained free and the only charges were for freight. A newly filled sewer 

 trench made it necessary to cross-reinforce a small part of the pavement 

 with 2-inch square twisted bars, 6 feet long and 12 inches center to center. 

 The cost of this section, exclusive of grading, was only $0.7336 per square yard. 

 This low cost was largely due to the free sand and crushed stone. 



Project No. 3 : 



Area of pavement laid square yards 5, 59-1 



Thickness of pavement inches 7 



Width of pavement feet IS 



Length of haul for materials mile I 



Cost of cement per barrel dollars 1. 025 



Amount of cement used per square yard barrel . 29 



This is a one-course pavement, and the coarse aggregate consisted of gravel. 

 Armored expansion joints were used. The thickness varies from S inches at 

 the center to 6 inches at the side. Congestion of traffic caused some expense 

 and delay. The cost, however, is only moderate. 



MAINTENANCE. 



The shoulders, slopes, and drainage structures of concrete roads 

 require the same kind of maintenance as other types of improved 

 roads and will, therefore, not be given special attention here. The 

 maintenance of the pavement consists, for the most part, in repairing 

 cup holes, cracks, contraction joints, and perhaps the renewal of an 

 occasional defective area. 



Cup holes are spots in the surface of the pavement which break 

 down imder traffic and which may result from any one of a number 

 of causes. The most frequent cause for such defects is the presence 



