Stress–Strain Relationship Model of Recycled Concrete Based on Strength and Replacement Rate of Recycled Coarse Aggregate

AbstractThe use of recycled coarse aggregate (RCA) can reduce the consumption of natural coarse aggregate (NCA) and preserve the natural environment. The accurate calculation of the compressive stress-strain relationship of recycled aggregate concrete (RAC) is very important in designing the recycled concrete structure. In this paper, experiments on compressive stress-strain based on five strength grades and six replacement rates of RCA from 0 to 60% were designed. The prism specimens of a height-to-width ratio of 3 were used to conduct the experiments under uniaxial compression load. The complete stress-strain curves were obtained by the experiments, and the ascending and descending branches of the experimental stress-strain curves are discussed separately. Based on the experimental results and by introducing the shape parameter β of the stress-strain curve, a theoretical model of the stress-strain relationship considering the strength and replacement rate of recycled coarse aggregate was established. Through comparison and analysis, the stress-strain curve of RAC obtained by the suggested model has good fitting accuracy.