Mesoscale fracture modeling of four-phase concrete using a dem-enhanced structure generation method

The two-dimensional mesoscale concrete model consists of aggregates, mortar, interfacial transition zones, and pores, of which each component is not negligible. This paper proposes a new approach to generate four -phase concrete models by assigning the geometries of small pores to fine aggregates, redistributing all aggregates via the DEM packing method with periodic boundary, and removing some aggregates based on specified pore area intervals and porosity. The size and geometry of aggregates and pores are random. Additionally, this work adopts the rigid block discrete element method to simulate the fracture behavior of these concrete models. Each rigid block is transformed from a finite element mesh, and there are no voids between them, which is more realistic than classical ball -based discrete elements. The effects of aggregate volume fraction, porosity, and pore size are also discussed. This work offers a more practical and effective approach to analyzing the impact of these factors on concrete.