Numerical assessment of reinforced concrete members incorporating recycled rubber materials

This paper is concerned with the inelastic behaviour of reinforced concrete beam-column members incorporating rubber from recycled tyres. Detailed three-dimensional nonlinear numerical simulations and parametric assessments are carried out using finite element analysis in conjunction with concrete damage plasticity models. Validations of the adopted nonlinear finite element procedures are carried out against experimental results from a series of tests involving conventional and rubberised concrete flexural members and varying levels of axial load. The influence of key parameters, such as the concrete strength, rubber content, reinforcement ratio and level of axial load, on the performance of such members, is then examined in detail. Based on the results, analytical models are proposed for predicting the strength interaction as well as the ductility characteristics of rubberised reinforced concrete members. The findings permit the development of design expressions for determining the ultimate rotation capacity of members, using a rotation ductility parameter, or through a suggested plastic hinge assessment procedure. The proposed expressions are shown to offer reliable estimates of strength and ductility of reinforced rubberised concrete members, which are suitable for practical application and implementation in codified guidance.