Effect of the recycled materials replacement rate from highway solid waste on concrete performance
This study investigates the influence of replacement rate for recycled coarse aggregate (RCA) and recycled fine aggregate (RFA) on the concrete performance in highway reconstruction and expansion projects, and provides theoretical and technical support for its application in non-load-bearing structures (NLBS) and pavements. Through the application research of RCA, the influences of different replacement rates were analyzed, including slump, compressive strength, splitting tensile strength, flexural tensile strength, and wear resistance. Combined with relevant test data, the nonlinear relationship between the replacement rate of RCA and the performance variation was summarized. The application of RFA in NLBS, the influence of RFA replacement rate on slump, compressive strength, and splitting tensile strength (STS) were discussed, and the sensitivity difference of RFA and RCA to concrete performance was compared. Research shows that when RCA is used for NLBS and pavements, the concrete slump reduces significantly when the rate exceeds 20%. In terms of mechanical properties, compressive strength decreases rapidly when the rate exceeds 50%, and STS also continues to decrease. In terms of durability, the flexural strength decreases significantly when the substitution rate exceeds 50%. For RFA in NLBS, both slump and compressive strength decrease sharply once the replacement rate exceeds 30%, while STS decreases continuously with the RFA content. Research recommends that the RCA rate does not exceed 50%, and the RFA rate does not exceed 30%.