Reuse of waste rubber in pervious concrete: Experiment and DEM simulation

The reuse of waste rubber has a profound impact on environmental protection and resource recy-cling. To evaluate the feasibility of adding waste rubber into pervious concrete, the effects of rub-ber content and particle size on the mechanical properties of pervious concrete are investigated through experiments and discrete element method (DEM) simulation. The compressive failure mode of pervious concrete gradually transits from tensile failure to shear failure with the increase of rubber content, showing a decrease in compressive strength, and the larger the particle size is, the stronger the attenuation effect on the strength is. Rubber particles play a role in isolating coarse aggregates from the cement matrix and form a weak bond with the matrix, showing a weak bridging effect in stress transmission at the left and right ends of the crack, so that the split-ting tensile strength of pervious concrete significantly decreases with the increase of rubber con-tent, and the weakening effect of coarse rubber on the splitting tensile strength is stronger than that of fine rubber. Due to the low strength of rubber itself and weak bonding with cement ma-trix, pervious concrete with high rubber content breaks in advance at the bottom of the midspan, resulting in the decline of flexural capacity, and it decreases more obviously with the increase of rubber size. Although the direct tensile strength of pervious concrete gradually decreases with the increase of rubber content, the addition of rubber improves the plasticity of pervious con-crete. Moreover, the plastic reinforcement effect of pervious concrete is the strongest when the rubber content reaches approximately 10%, and this toughening effect increases with the de-crease of rubber size. On the basis of experimental research, a universal DEM model considering rubber content and particle size is established, which can well predict the mechanical perfor-mance of rubberized pervious concrete in terms of strength, failure mode, elastic modulus and ul-timate strain.