A study of carbonation resistance when recycled coarse aggregates were used to make new concrete was conducted.Effects of water-binder ratios(m_w/m_b),cement content,the kinds of mineral admixture,the quality of recycled coarse aggregates,recycled coarse aggregate replacement rate for natural coarse aggregates and loading levels on the carbonation behavior of recycled concrete were evaluated by accelerated carbonation experiments.The results show that carbonation behavior of recycled concrete is not only determined by the quality of new mortar but also by the quality and quantity of recycled coarse aggregates,the addition of mineral admixture replacing cement partially seems to accelerate carbonation;its loading levels may have a significant impact on the propagation of the carbonation.