Influence of Crack Orientation of ASR Expansion Under Restraint Condition on Compressive Behavior Evaluated by Mesoscale Discrete Model

The influence of crack orientation in concrete due to the alkali–silica reaction (ASR) under restraint conditions on the change in compressive behavior is numerically evaluated. In the analysis, aggregates and mortar are modeled separately using a 3D rigid-body spring model. The mechanism of generating expansion pressure inside aggregates is described using the expansion model. ASR expansion under various restraint directions is simulated to reproduce the crack orientation due to ASR and then uniaxial compressive loading is performed. It is observed that crack orientation is parallel to the restraint direction and also affected the compressive behavior. Expansion cracks perpendicular to the loading axis caused a large reduction in compressive strength and elastic modulus. Furthermore, the stress distribution in a cross section during loading indicates that cracks parallel to the loading axis do not strongly affect compressive stress transfer, whereas perpendicular cracks prevent compressive stress transfer.