PORTLAND CEMENT CONCRETE PAVEMENTS. 25 



600 feet of rubber hose, with couplings $120 



20 wheelbarrows 100 



1 concrete mixer, with skip and distributing device 2, 000 



Strike board, tamper, mortar hoes, sledges, etc 100 



Total 6, 875 



Ordinarily the method of paying for the work should enable the 

 contractor to meet most of his bills for labor and materials after the 

 first one or two estimates, so that the total amount of capital required 

 for carrying on the work need not greatly exceed the cost of the 

 equipment. For the average small project, where no very elaborate 

 equipment is required to handle the materials, it seems that a total 

 working capital of about $10,000 should be sufficient. 



COST. OF CONCRETE PAVEMENTS. 



The cost of concrete pavements is almost wholly dependent on 

 local conditions, and the conditions are seldom exactly the same, 

 even for two projects in the same locality. It is therefore evident 

 that a tabulation of cost figures for projects which have already 

 been completed would be of little service in estimating the cost of 

 new work, unless the conditions which affected the cost of the com- 

 pleted work could be fully compared with those under which the 

 proposed work is to be done. Furthermore, some of the conditions 

 which affect the cost of work are extremely uncertain. Among these 

 are the weather, the efficiency of labor, and what is commonly called 

 the element of luck. These may all influence the cost of a project to 

 a considerable extent, but their influence can seldom be expressed in 

 definite figures. 



The most satisfactory method of arriving at the probable cost of a 

 proposed pavement is first to ascertain by careful measurements and 

 computations the quantities of the materials to be used and the va- 

 rious kinds of work to be done. An itemized estimate based on these 

 quantities and the unit costs which prevail in the community for such 

 materials and work may then be made. To this estimate should or- 

 dinarily be added a reasonable amount to cover unforeseen con- 

 tingencies, and, also, if the work is to be done by contract, a fair 

 profit for the contractor. From 15 to 20 per cent of the estimated 

 cost is usually considered sufficient to cover these items. 



In order to appreciate the importance of considering the different 

 items separately in preparing an estimate of cost, it is necessary only 

 to consider briefly the great amount of variation in unit costs. 



The grading is usually paid for by the cubic yard of excavation, 

 and the cost varies not only with the quantity but is greatly influenced 

 by the character of the soil. In light, easily loosened soils grading 

 may usually be done at from 25 to 40 cents per cubic yard. In hard 

 earth containing more or less loose rock the cost per cubic yard gen- 



