A new DEM-based method to predict packing density of coarse aggregates considering their grading and shapes

The grading and shape of aggregates have significant effects on the performance of fresh and hardened concrete. Aggregate blends with maximum packing density (PD) require lower amounts of paste to fulfill voids between aggregates and as a result, they are less expensive and have less durability problems. Different methods have been presented by researchers and codes to determine PD of aggregates considering grading; however, there are a few methods that consider the shapes of aggregates. In the current research, using computer simulation software based on discrete element method (DEM), a new method was developed to predict PD of coarse aggregates with regard to grading and shape of aggregates. In this method, all aggregates are modeled as sphere but, as for the shape of aggregates, a friction coefficient, μ is determined for each aggregate. Effectiveness of this method has been substantiated by different computer modeling and laboratory experiments.