Effects of aggregate fragmentation, free water and strain rate on fracture in compressive concrete with a coupled DEM-CFD approach

The impact of aggregate fragmentation, free water, and strain rate content on the dynamic behavior of concrete under the uniaxial compression state at the mesoscale was examined in this study.Extensive two-dimensional (2D) dynamic investigations were conducted to examine the impact of aggregate fragmentation and strain rate on concrete's dynamic strength and fracture patterns.The behavior of fully and partially fluid-saturated concrete was simulated using a mesoscopic pore-scale hydro-mechanical model based on a unique fully coupled DEM/CFD approach wherein a DEM-based breakage model was used.Concrete was simulated as a four-phase material consisting of aggregate, mortar, ITZs, and macropores.The concrete mesostructure was obtained from laboratory micro-CT tests.Collections of small spherical particles were used to imitate aggregate breakage of different sizes and shapes by enabling intra-granular fracturing between them.The dynamic compressive strength increased with the strain rate, fluid saturation, and aggregate fragmentation.