Discrete element modeling of cemented recycled concrete aggregates under unconfined and k0 loading conditions

Abstract

Abstract Construction and demolition (C&D) wastes are being extensively utilized in pavement and railway construction projects. Chemical stabilization with binders such as cement enhances the physical and strength properties of C&D materials. In this study, a numerical model has been developed to simulate the macro- and micro-mechanical properties of lightly cement stabilized recycled concrete aggregates (RCA) under unconfined compression and k0 loading-unloading condition. The model considers the unique nature of RCA materials in terms of particle size distribution and void ratio. The cement chains were utilized to simulate the cementation product and can be altered to model samples with various cement contents and curing conditions. Results indicated that the proposed model performed well in estimating the stress-strain behavior of cemented RCA sample under unconfined compression test as well as estimating the changes in the sample’s void ratio during one-dimensional compression test (k0 loading condition). The results of the micro-scale analyses indicated that during uniaxial loading the contact forces did not change direction significantly, while the magnitude of the forces transmitted through the sample increased markedly. The parametric analysis results furthermore demonstrated that the cement contact bond parameters strongly affected the performance of the numerical model.