Concrete Mix Design

The concrete mix design must be correctly proportioned so that the concrete will flow easily and uniformly through the pipe. The pipeline diameter should be 3-1/2 to 4 times greater than the maximum aggregate size for pumped concrete. This helps ensure that the pipeline will not become clogged. Another factor in mix design is the slump of the pumped concrete. A higher slump will cause concrete to flow more readily, making the concrete easier to pump.

However, an excessively high slump can cause the concrete to separate, resulting in plugs in the pump or line.

What makes concrete Pumpable? Pumpable concrete can be pushed under pressure through a pipeline , the concrete is separated from the pipeline wall by a lubricating layer of water, cement, and sand (mortar). A concrete mix must be such that the concrete can pass through reducers in the pipeline system, and can go around bends in the line. In order to obtain this type of pump ability, the mix must be dense, cohesive, and have sufficient mortar. (Mortar required depends on the line size, efficiency of concrete pump, and pressure available for pumping concrete).