Segregation of granular materials in a pulsating pumping regime

The segregation of particles in a granular material is a well known effect of high importance in many industries. Concentrated suspensions like concrete are strongly influenced by the behavior of the coarse aggregates. In these suspensions, the segregation also occurs, especially during the transport of the material through pipes. Typically, concrete is pumped by using double piston pumps leading to a pulsating pumping regime in contrast to a linear (continuous) pumping. This paper shows the behavior of particles during the pulsating pumping regime and the migration in the tube axis. Discrete element simulations of dry, bidisperse materials were carried out to show the influence of material parameters and the segregation behavior. Detailed understanding of the dry material behavior is of great importance for the interpretation of characteristic phenomena, which can be also found in concentrated suspensions, like the formation of a lubrication layer during the concrete pumping.