Micromechanical Modeling of Cement-Treated Base Materials Considering Recycled Crushed Aggregate Morphology from Construction and Demolition Waste Using Three-Dimensional Discrete Element Method

This study established a three-dimensional discrete element method (3D DEM) of cementtreated base materials (CTBM), considering the morphology of recycled crushed aggregates (RCAs) derived from construction and demolition waste. Coarse RCA morphology was obtained using X-ray computed tomography and integrated into the DEM model. The linear contact model and linear parallel bond model were selected and key microparameters were determined. The developed 3D DEM model was verified through the actual indirect tensile test of CTBM. Micromechanical analysis, encompassing contact force and displacement fields of particles, was subsequently evaluated based on the virtual uniaxial compression test. The findings revealed that particles near the loading plate exhibited relatively higher contact force, gradually decreasing with distance from the loading position. Regarding the displacement field, the particles closer to the edge of the cross-section and the loading plate on the longitudinal section experienced greater displacement, whereas those in the middle of the specimen and farther from the loading plate had smaller displacements. Furthermore, it was observed that increasing the cement content effectively enhanced the internal contact force and the ability of CTBM to resist uniaxial deformation.