SIMULATING FRESH CONCRETE BEHAVIOUR - ESTABLISHING A LINK BETWEEN THE BINGHAM MODEL AND PARAMETERS OF A DEM-BASED NUMERICAL MODEL

The rheological behaviour of fresh concrete can be described reasonably well by the Bingham model, whose parameters can be used directly in numerical simulations by means of the Single Fluid approach. In many instances, however, it is advantageous to use the Distinct Element Method (DEM) instead of the Single Fluid approach. The difficulty is that yield stress and plastic viscosity, the parameters of models based on DEM, are not rheological constants and they cannot be obtained directly from experiments. Hence, the aim of the ongoing research project is to establish a link between the theological properties of fresh concrete and the parameters of a DEM-based model. In this paper, an algorithm is presented to derive the model parameters connected to yield stress according to the Bingham model. For this an analytical prediction of stress-distribution at the beginning of the slump-flow test is used as reference for the corresponding numerical analysis. For the sake of verification, the analytical and numerical predictions of the final shape of the concrete cake are compared.