54 BULLETIN 1077, U. S. DEPARTMEISTT OF AGRICULTURE. 



The magnitude of the work should be a guide in purchasing equip- 

 ment. One 2-sack mixer would be as much out of place on a 10- 

 mile contract as an 8-sack mixer would be on a 1-mile contract. Con- 

 sidering the two extremes of too little equipment and too much 

 equipment, the tendencj' of contractors, especially those just enter- 

 ing this class of work, is toward too much equipment. The success 

 of a contractor upon the completion of any work should be meas- 

 ured by the amount of money the work has produced, not by the 

 amount of equipment he has on hand. The aim of the contractor, 

 therefore, should be to finish the work in the specified time and use 

 the smallest amount of equipment with which operations can be car- 

 ried on economically. 



The capacity of each piece of equipment purchased should bear 

 its proper relation to the capacity of the combined equipment in or- 

 der that all parts may be nicely balanced. A large mixer with a 

 small unloading plant or poor transportation facilities would be a 

 poorlj^ balanced equipment on which the contractor would not re- 

 ceive proper returns in efficiency for his expenditure. 



The following list, based upon 1920 prices, will give some idea 

 of the cost of the various kinds of equipment used in building con- 

 crete pavements: 



Locomotive cranes with clamshells each__ $15, 000. 00 to $20, 000. 00 



Automotive cranes with clamshells clo__- 6, 500. 00 to 12, 000. 00 



Derrick cranes witli clamshells (lo_— 4, 500. 00 to 6, 500. 00 



Mixers — 4-sack capacity do 6, 500. 00 to 9,000.00 



Road rollers — macadam type do 3, 500. 00 to 4, 800. 00 



Industrial locomotives : 



Gasoline do— 2, 500. 00 to 4, 500. 00 



Steam do___ 5,000.00 to 8,000.00 



Industrial railway cars do 75. 00 to 90.00 



Industrial railway track, 24-inch gauge per mile 4, 500. 00 to 5, 800. 00 



Industrial batch boxes each 35. 00 to 70. 00 



Concrete finishing machines do 1, 600. 00 to 2, 000. 00 



Steel forms per lineal foot . .50 to . 60 



Subgrade planer each__ 400. 00 to 500.00 



Water pmup do 600. 00 to 1, 000. 00 



2-inch wrought-iron pipe per lineal foot — . 22 to . 25 



Tractors, caterpillar, 5-tou each__ 5, 500. 00 to 6, 500. 00 



Trucks. 3-ton capacity, with dump bodies do 3, 000. 00 to 5, 000. 00 



The equipment necessary for doing the rough grading and build- 

 ing culverts in connection with concrete pavement work is not 

 essentially different from that required for other types of pavements 

 and needs no particular discussion here. 



The total expenditure for equipment for preparing the subgrade 

 mixing and placing and finishing the concrete depends on the rate 

 at which it is proposed to carry on the work. Based on 1920 prices 

 for equipment, a wheelbarrow outfit, consisting of a four-sack mixer, 



