Mesoscale analysis of rubber particle effect on young’s modulus and creep behaviour of crumb rubber concrete

This paper presents a mesoscale model to investigate the rubber particle effect on the mechanical properties of crumb rubber concrete (CRC). Taking Young’s modulus as an example, the short-term and long-term compressive behaviour of CRC with varying rubber percentages, shapes, and sizes were simulated. As the first step of the simulation, the Walraven equation was used to convert the 3D distribution of coarse aggregate and rubber particles in an actual specimen to a 2D distribution in a plane state. Then four differently shaped coarse aggregates and rubber particles including circular, elliptical, circle-derived polygonal, and ellipse-derived polygonal aggregate were generated. Based on an overlap judgement algorithm, Python programs were compiled to create a three-phase mortar-coarse aggregate-rubber CRC model and a two-phase concrete-rubber CRC model. All results from both models with varying particle shapes are within the range of experimental values. When the rubber content of CRC samples was 18%, the maximum deviation between the two-phase model and the three-phase CRC model was only 1.4%. Numerical results verified that incorporating rubber particles in concrete reduced material rigidity. The rubber percentage was the main influencing factor on the reduction rate of Young’s modulus of CRC, while the influence from varying crumb rubber particle shapes and sizes was ignorable. For practical applications, a prediction formula for Young’s modulus of CRC was provided. The proposed mesoscale model was also applied to the creep behaviour analysis of CRC, showing that the addition of crumb rubber particles had little effect on the creep coefficient of rubber concrete. The numerical results agreed well with the experimental study.