Influence of axial loading and carbonation age on the carbonation resistance of recycled aggregate concrete

This paper presents the results of research on the carbonation resistance of recycled aggregate concrete (RAC) and natural aggregate concrete (NAC) under loading. The correlation between axial stress/carbonation age and the carbonation depth was analyzed. Based on theoretical analysis and experiment results, a model to predict the carbonation depth of RAC under axial stress was established. The carbonation depths of NAC and RAC under the same experimental parameters were compared and results were discussed. The experimental results show that the carbonation depth of RAC first decreases and then increases with an increase in axial compressive-stress ratio, and consistently increases with a growing of axial tensile-stress ratio. The experimental data also demonstrate that the carbonation depth increases with the carbonation age, and that the carbonation resistance of RAC is lower than that of NAC under the same experimental conditions.