Effect of epoxy resin surface-modified techniques on recycled coarse aggregate and recycled aggregate concrete

The absorption of water by recycled coarse aggregates (RCAs) is significantly greater than that by natural coarse aggregates (NCAs), which affects the mechanical properties of recycled aggregate concrete (RAC). To mitigate this issue and enhance the mechanical strength of RCAs, a water-based epoxy resin was utilized to wrap an RCA, resulting in modified RCA (MRCA). Subsequently, MRCA and unmodified RCA (URCA) were mixed in various proportions and substituted for NCA in concrete, followed by performance evaluation. The experimental results showed that the MRCA absorbed 36.5% less water than did the RCA, and the compressive and tensile strengths of modified RAC (MRAC) were 11.3% and 4.2% greater than those of nature aggregate concrete (NAC) and 8.2% and 2.9% more than those of unmodified recycled aggregate concrete (URAC), respectively. This finding provides a strategy and possibility for the preparation of concrete using recycled aggregates.