Massive base mat pours or high-rise projects may include pump placements of thousands of cubic yards of concrete. These record-setting projects sometimes obscure the fact that pumps are used on many small- to medium-sized pours as well.
PUMPS MOUNTED ON TRAILERS
Trailer-mounted pumps can be used on smaller jobs to move concrete through placement lines with diameters anywhere from 2 to 5 inches. Smaller trailer pumps are used advantageously to place concrete for patios, swimming pools, sidewalks and similar projects in residential neighborhoods. One disadvantage of trailer pumps is the time required to set up the line system. And if high production rates in cubic yards per hour are required, the smaller pumps may not have enough capacity.
TRUCK-MOUNTED PUMPS WITH PLACING BOOMS
Using a truck-mounted concrete pump with placing boom, a pump operator can drive to the jobsite and be ready to pump soon after he arrives. Very little breakout and setup time is needed. He can boom up and out, quickly delivering concrete to most hard-to-reach spots. Pumping booms have vertical reaches of 60 feet and up and line diameters of 3, 4 or 5 inches. The reach of boom pumps can be further extended by attaching the boom to a pipeline system set up at the jobsite.
For any concrete pump, the maximum attainable output in cubic yards per hour will decrease as line resistance increases. Factors that increase line resistance include: longer lengths of horizontal line; line that rises vertically; smaller line diameters; changes in line diameters (reducers); bends in the line. Slump and other concrete properties also affect line resistance.
The basic requirements for a fast-moving, smooth-running pump pour are a level site for the pump, with room to get ready mix trucks in and out; timely delivery of a pumpable concrete; and enough people on the placing and finishing crews to handle the concrete.