Cyclic stress-strain relation of recycled aggregate concrete under confining pressure

This paper focuses on investigating the cyclic stress-strain relation of recycled aggregate concrete (RAC) subjected to triaxial compression. Five sets of RAC specimens with various recycled coarse aggregate (RCA) contents were prepared and tested under four levels of confining pressures. Two loading regimes, i.e. monotonic and cyclic loading, were both considered to investigate the mechanical behavior of the RAC under confining pressure. The outcomes indicate that both the RCA content and the confining pressure have impacts on mechanical performance and stress-strain curves of the RAC, while the latter appears more prominent. Additionally, compressive meridian curves of the RAC subjected to triaxial compression are established utilizing well-known failure criterions originally developed for the normal concrete (NC). Furthermore, the plastic-damage constitutive relation is established for the RAC considering the influences of confining pressure and RCA content, which is further verified by the experimental results in this paper and other studies. It demonstrates that the proposed constitutive relation is competent in predicting the stress-strain behavior of RAC under confining pressure.