Impact of aggregate shape on drying shrinkage cracking in concrete: a three-dimensional hydro-mechanical peridynamic model

The crack evolution in concrete under drying conditions is significantly influenced by the shape of aggregates.This study presents a fully coupled three-dimensional hydro-mechanical peridynamic (PD) meso-scale model for partially saturated porous media to simulate crack formation in cementitious materials during drying shrinkage.Simulations were conducted on concrete samples with different aggregate shapes, including regular polyhedron (e.g., hexahedron, octahedron, dodecahedron, and icosahedron) and spheres.Results indicated that aggregates with lower sphericity led to higher stress concentrations and an increased formation of fine internal cracks.In contrast, aggregates with higher sphericity, such as spheres, produced a more uniform damage distribution, with fewer surface cracks.Damage analysis demonstrated that the sphericity of aggregates influenced early surface damage and denser crack networks, while higher sphericity in aggregates reduced the overall volume of internal cracks.The evolution of internal cracks over time underscored the sensitivity of the concrete matrix's mechanical response to aggregate morphology.This fully coupled hydro-mechanical PD model enhances our understanding of fracture behavior in concrete under drying conditions and underscores the critical role of aggregate shape in crack development.The insights gained from this study support optimized aggregate selection and improved structural design strategies to minimize drying shrinkage damage, contributing to the durability of concrete structures.