Guide to concrete pumps
Pumping is an efficient way of placing concrete. It avoids overhandling, saves time, and increases productivity.
Sometimes, using a pump is the only means of getting concrete into areas inaccessible to a ready-mix vehicle. In other cases, the efficiency of concrete pumping makes it the preferred solution.
How to configure a concrete pumping operation
The most efficient configuration of a concrete pumping system is essential to optimise the operation.
This entails determining the right line pressure to deliver the concrete at a specified flow rate through the particular diameter and length of the pipeline.
Pump lines with a larger diameter need less pumping pressure but can require more labour and bracing and blocking. The maximum size of the aggregate should be no more than a third of the line diameter.
Longer pump lines – including the length of hose at the end of the pipeline – mean the concrete will encounter more friction. This resistance can be reduced by using steel pipelines with smooth walls.
Other considerations affecting pump line pressure include:
- Vertical and horizontal distances. It takes more pressure to pump concrete over greater distances. In these cases, using two pumps and two lines may be the best solution, with one pump feeding into the second.
- Reducing sections. Reductions in pipe diameter will increase resistance. If reductions can’t be avoided, longer reducers will cause less resistance.
- Bends in the pipeline. Minimising bends in the pump line will reduce the resistance caused by changes in direction.
Lubrication for pumpable concrete mixes
Concrete pumps need a lubricating layer of sand, cement and water to separate the concrete from the walls of the pump line.
This allows a pumpable concrete mix to flow easily through the bends of the pump line, and pump primers can prevent many potential problems associated with pumping concrete.
Some mixes are unsuitable for pumping. They either won’t pump at all or clog the pump lines.
Boom pumps and line pumps
Concrete boom pumps are typically used for pours over greater vertical or horizontal distances. They can also be manoeuvred around the pour site more easily than line pumps.
Different sizes of boom pumps are available to handle a wide range of concrete pouring work, including:
- Multi-storey constructions.
- Car parks.
- House slabs.
Concrete line pumps mounted on trailers provide a more affordable solution than boom pumps for smaller concrete pouring jobs and on sites where there’s insufficient room for a boom pump.
Typical line pump applications include:
- Footings and Steps
- Cavity walls.