Evolution of Pore Structure and Meso-Damage Simulation of Aeolian Sand Self-Compacting Concrete Under Freeze–Thaw Cycles

Currently, existing studies primarily perform damage simulations based on random aggregate mesoscale models of concrete. In contrast, research on freeze–thaw numerical simulations based on realistic concrete mesostructural models remains relatively scarce. In this study, based on X-ray computed tomography (CT) scanning technology, the influence of freeze–thaw action on the pore structure evolution law of aeolian sand self-compacting concrete (ASSCC) was analyzed. Mesoscale characteristics of the mortar, aggregates, and pores were extracted using image processing software, and a realistic mesostructural model of ASSCC was subsequently established. Furthermore, numerical simulations of the freeze–thaw cycle process were conducted using the finite element software ABAQUS. The results indicated that during the initial freeze–thaw stage, the formation of small new pores predominated within the concrete. As the freezing and thawing cycles progressed, these pores gradually interconnected and coalesced into larger irregular pores, which eventually led to the development of penetrating cracks that resulted in structural failure of the ASSCC. The mesostructural model derived from CT data effectively simulated the failure patterns and mechanical performance of ASSCC under both uniaxial compression and freeze–thaw conditions. This provides an effective means for predicting the mechanical properties of concrete under freeze–thaw cycling conditions.