In pumping operation, the force exerted by pumps must overcome the friction between
concrete and the pumping pipes, the weight of concrete and the pressure head when placing
concrete above the pumps. In fact, as only water is pumpable, it is the water in the concrete
that transfers the pressure.
The main problems associated with pumping are the effect of segregation and bleeding. To
rectify these adverse effects, the proportion of cement is increased to enhance the cohesion
in order to reduce segregation and bleeding. On the other hand, a proper selection of
aggregate grading helps to improve the pumpability of concrete.
