Answer :
During the pumping operation the pump exerted pressure must overcome any friction between
the pumping pipes and the concrete, also the weight of the concrete and the pressure headwhen the concrete is placed above the pumps. Since only water is pump able, all the pressure
generated is by the water that is present in the concrete. The major problem due to pumping are
segregation effects and bleeding. In order to rectify and reduce these effects, generally the
proportion of the cement is increased in order to increase the cohesion , which leads to the
reduction of segregation and bleeding. Also if a proper selection of the aggregate grading can
vastly improve the concrete pump ability.