Crushing behavior of recycled waste materials: Experimental analysis and DEM simulation

Abstract Sustainable usage of construction and demolition (C&D) wastes in pavement and railway structures has attracted attention globally. However, the high probability of C&D particle breakage can impact the performance of the material and calls for careful investigation and assessment. This study aims to investigate the particle shape effect on the breakage behavior of C&D aggregates under one-dimensional compression testing using the discrete element method (DEM). Crushable particles with realistic particle shapes were modeled by agglomerates of bonded sub-particles based on 3D laser scanning technique. The DEM model was calibrated and validated with a series of single-particle crushing experiments. Results of single crushing tests indicated that the particle shape had a considerable effect on the crushing strength of the tested materials. Comparable macro-mechanical results were observed between the DEM simulation of the one-dimensional compression test and the laboratory experiment. The results revealed that the proposed model is able to accurately capture the macro and micro-mechanical responses of the tested samples. The percentage of broken bonds, number of agglomerates and volumetric size distribution of recycled concrete aggregate (RCA) materials during compression is shown to be significantly affected by the particle shapes. A hyperbolic equation is furthermore proposed to capture the correlation between the dissipated energy and the volumetric breakage index.