Effect of carbonated recycled coarse aggregate on the dynamic compressive behavior of recycled aggregate concrete

Adopting accelerated carbonation technique is one of ways to improve the properties of recycled coarse aggregate (RCA). In this study, the uni-axial dynamic compressive behavior of recycled aggregate concrete (RAC) and RAC with carbonated RCA (CRAC) was experimentally investigated when the strain rates were between 10−5/s and 10−1/s. The strain-rate sensitivities of RAC and CRAC were evaluated from the effect of strain rate on stress-strain curve, peak stress, peak strain, ultimate strain, elastic modulus, energy absorption capacity and failure pattern. The results showed that the uni-axial compressive stress-strain curves given in the Chinese code agreed well with the experimental results. As the strain rate was increased, the peak stress, elastic modulus and energy absorption capacity showed an increasing trend for both RAC and CRAC. The peak stress and elastic modulus of CRAC were higher than that of RAC. The strain-rate sensitivity of peak stress and elastic modulus of CRAC was less obvious than that of RAC, which may be explained from Stefan effect and strain-rate sensitivity of crack propagation resistance.