Exploring effects of initial water content of recycled aggregate and additional water consumption on the permeability resistance of concrete to chlorine salt

Abstract

Recycled aggregate concrete (RAC) technology is conducive to resource conservation and environmental protection, but the high-water absorption of recycled aggregate makes it difficult to control the durability of RAC. In this study, the combined effects of initial moisture and additional moisture of recycled coarse aggregate (RCA) on the resistance to chloride ion penetration of concrete were investigated. The results show that, when the initial humidity of RCA is lower than 0.25 and the additional water consumption is low, RAC shows a rapid decay of dynamic elastic modulus. In contrast, when the sum of initial water content and additional water content is greater than 80%, the higher the initial water content, the better the compactness and impermeability of concrete. At the same time, the initial water and additional water of RCA have a great impact on the quality of RAC and the depth of damage layer. When the initial water content of RCA is high, the corrosion resistance of RAC decreases with the increase of the additional water. After comprehensive consideration, it is recommended to use RCA with 50% initial water and less than 40% additional water to obtain good durability.