Simulating macroscopic behavior of self-compacting mixtures with DEM

Development of proper rheological models and suitable numerical methods are necessary for a thorough understanding of the basic flow properties of fresh mortar or concrete. Main challenge for models is to find a quantitative correlation between the model parameters and the properties and proportions of the mix ingredients. This paper presents a modeling approach for the rheological behavior of fresh self-compacting mixtures using a Discrete Element Method (DEM). The employed method is based on a conceptual idea where the grain-paste-grain interactions are explicitly described as an interactive two-phase paste-bridge system. Each mixture is considered to be an assembly of mutually interacting “grain-paste-grain” systems which can be characterized according to the mix composition with help of the “excess paste theory”. Macroscopic slump flow predictions are evaluated by laboratory tests. Simulations and experimental test results show good agreement.