The effect of curing conditions on the compressive strength of recycled aggregate concrete

This work assesses the influence of different curing conditions on the compressive strength of recycled aggregate concrete. Two different qualities of recycled aggregate were used to make concrete with 0.65 water/cement rate. The recycled aggregates were added with their natural moisture and they replaced different percentages of the coarse aggregate (0%, 20%, 50% and 100%). The concrete specimens were exposed to two different environments (standard curing and open-air curing) for 28 days. The results showed that the 7-days strength increases with the percentage of replacement, being this behavior more evident for the standard curing environment. The 28-days compressive strengths of concretes with recycled aggregates were found similar to the ones obtained with natural aggregate when the standard curing environment was considered. However, the recycled aggregate concrete specimens lost up to the 20% of their compressive strength when they were cured in open-air conditions. This made evident the effect of the curing conditions on the resistance of recycled aggregate concrete. (C) 2013 Elsevier Ltd. All rights reserved.