A DEM hard-core soft-shell model for the simulation of concrete flow

A new DEM model for the simulation of concrete flow is presented. Fresh concrete is described as an assembly of composite particles made of spherical hard grains representing coarse aggregates surrounded by concentric spherical layers representing mortar. Two kinds of simulations are carried out: rheological simulations performed in a Couette geometry and slump test simulations. Rheological simulations show that the rheological behaviour of simulated concretes can be approximated with the Bingham model. The force model used allows for a direct relation between rheological characteristics of the mortar and rheological characteristics of the simulated concrete. Slump test simulations show that the model is able to describe the shape of concrete during the flow. The yield stresses and viscosities of numerical concretes are then calculated from the slump values and slump times with equations of the literature.