Elasto-Damage constitutive modelling of recycled aggregate concrete

In this paper, Elasto-Damage model previously proposed by Khan and Zahra for natural aggregates concrete is reformulated to capture the behavior of recycle aggregate concrete (RAC) subjected to uniaxial compressive stress state. The compressive stress-strain relationship was investigated through existing published data for different recycled coarse aggregate (RCA) with replacement percentages of 0%, 30%, 50%, 70% and 100%. Use of recycled aggregate concrete has been advocated widely to be one of the solution for the global issue of depletion of natural resources while fulfilling the needs of material and structural performance required in reinforced-concrete structures. The adoption of RAC in construction industry requires development of appropriate constitutive models that can be implemented in software based on finite element method to predict the reliable results. The proposed model uses four parameters; a, b and r which helps to predict the different behavior of concrete in tension and compression while the fourth parameter critical energy release rate (Rc) controls the damage growth rate. These parameters are defined as a function of concrete compressive strength (fc') and its initial elastic modulus (Eo). The model is validated through existing test results for uniaxial compressive state of stress and it was concluded that it predicts better post cracking and post peak-behaviour of RAC as compared to the commercially available models for the conventional concrete.