Pre-and post-peak stress-strain response of recycled aggregate concrete: Experimental and numerical investigation

Use of recycled concrete aggregates (RCA) in structural concrete necessitates the understanding of complete stress-strain response of recycled aggregate concrete (RAC). An experimental and numerical investigation, was therefore, carried out to study and simulate the complete, pre-and post-peak, stress-strain response of RAC under uniaxial compression and is presented in this paper. Concrete cylinders cast with natural aggregates and RCA were tested under uniaxial compression and splitting tension to determine the compressive and splitting tensile strength along with the elastic modulus and Poisson's ratio. Experimental stress-strain curves were also produced. Cylinders were cast with different replacement percentages of RCA i.e., 0%, 30%, 50%, 70% and 100% and water-to-cement ratios of 0.43, 0.5 and 0.6. An equation for the estimation of uniaxial compressive strength of RAC has been proposed. Predicted compressive strengths compare well with the experimentally observed strengths. Experimentally measured elastic modulus and Poisson's ratio along with estimated compressive strengths were used in the elasto-damage constitutive model, proposed previously by the authors, to compare the stress-strain curves predicted by the model with the experimental stress-strain curves for uniaxial state of stress. Overall comparison of predicted stress-strain curves was found to be in good agreement with the experimentally exhibited stress-strain curves.