Micromechanical behavior of cement-treated base materials incorporating recycled crushed aggregates arising from C&D waste powder based on DEM

A numerical simulation of the uniaxial compression test (UCT) was conducted based on the discrete element method (DEM), to investigate the mechanical properties of CTBM incorporating recycled crushed aggregates (RCAs) arising from construction waste powder. The components of CTBM were generated via the randomization method to obtain a 2D DEM model. Then, the Linearcbond Model and Linearpbond Model were selected, and the effects of the main micro-parameters of contact models on the stress-strain curves of CTBM were clarified. The final micro-parameters were determined through the trial and error method and inversion analysis. Moreover, the micromechanical results presented that the contact forces between particles during the whole loading process increased continuously until damage occurred. And the contacts between particles failed at the middle and later loading stages, especially the tension contacts. The contact number of the Linearcbond Model reduced significantly, while that of the Linearpbond Model only decreased by 2.6%. Furthermore, the upper and lower particles moved to the mid-span of the specimens, and the particles in the middle moved to both sides when loading. The displacement on both sides was larger due to the failure of the specimen in the middle and later loading periods. The presented 2D DEM has the potential to display the mechanical characteristics of CTBM. It also provides theoretical guidance for the wide application of RCAs due to their great economic and environmental benefits.