This paper proposes a numerical approach based on the Distinct Element Method (DEM) as a means of fresh concrete simulation during its different working processes. A rheological model for concrete in a fresh state was developed and implemented in a DEM code. An extensive study followed to investigate the effect of various model parameters on the results of the numerical simulation of the slump test. The calculation results were discussed with regard to the correct choice of values for the model parameters as required for a realistic description of specific material behaviour.