Abstract:
This study experimentally investigated the mechanical behavior of carbon fiber reinforced polymer (CFRP) confined recycled aggregate concrete (RAC) under cyclic loading. In total, 72 CFRP-confined circular RAC specimens were tested under monotonic and cyclic axial compression, with a focus on the various loading rates and recycled aggregate (RA) replacement ratios. Test results indicate that the reinforcing effect of CFRP confinement on the ultimate condition of the concrete with 100wt%RA replacement ratio is most pronounced. However, this enhancement diminishes as the loading rate increases. In comparison to a loading rate of 3 mm/min, for two layers of CFRP-confined concrete with 100wt%RA replacement ratio, the enhancement ratio in ultimate strength is reduced by 16.2%, and the enhancement ratio in ultimate strain is reduced by 22.6% at a loading rate of 18 mm/min. Furthermore, under cyclic axial compression loading, both the unloading stiffness and reloading stiffness exhibit a negative correlation with the RA replacement ratio and loading rate. Nevertheless, the loading rate increase weakens the RA ratio's influence. Based on a regression analysis of the experimental data, a new cyclic stress-strain model for CFRP-confined recycled aggregate concrete incorporating the coupled effects of loading rate and RA replacement ratio is proposed. The proposed model exhibits excellent agreement with the experimental curves in this paper and the collected stress-strain curves from the opening literature.