LAUSR

Abstract To understand the degradation of mechanical properties of recycled aggregate concrete(RAC) after acid rain exposure, the effect of recycled coarse aggregate (RCA) replacement ratios, the acidity (pH value) of the simulated acid rain solution and mineral admixtures on compressive strength and elastic modulus of RAC are investigated in this study. The test results showed that elastic modulus and the compressive strength of RAC specimens may increase slightly at the beginning of acid rain spraying, then decreases gradually with the continuous erosion of acid rain. The greater the acidity of acid rain solution is, the more obviously the mechanical properties of RAC decreases. Appropriately adding fly ash and silica fume separately or together will effectively improve the strength and the acid rain resistance of RAC, whereas higher replacement rate of RCA may be unfavourable for RAC to resist acid rain. SEM/EDS observation and analyses also further illustrated that the impact of acid rain and mineral admixtures on the microstructures of ITZ in RAC.