Examining the Effect of Coarse Recycled Concrete Aggregate on Moisture Damage Resistance of HMA Mixtures

Moisture damage in asphalt mixtures has become a widely discussed topic due to its high influence on asphalt mixture behavior. Moisture damage is a phenomenon that relates to the loss of stiffness and strength of asphalt mixtures because of exposure to moisture under the influence of mechanical loading of traffic, which results in what is known as stripping. Moisture damage that leads to the deterioration in the integrity of asphalt pavement plays a key role in the occurrence of other distress types including fatigue cracking, rutting, etc. Therefore, this study aims to evaluate the influence of the addition of coarse recycled concrete aggregate (CRCA) on the tensile strength and moisture sensitivity of Ontario Superpave mixtures. Mix designs of asphalt mixtures were performed for two types of CRCA at various proportions (0%, 15%, 30%, and 60%). The impact of CRCA types on the tensile strength and moisture sensitivity of asphalt mixtures were evaluated. The obtained results also are statistically analyzed. The findings showed that the tensile strength of hot mix asphalt (HMA) mixtures that included different CRCA types with various proportions have higher values than the control mix. Additionally, the laboratory outcomes revealed that all TSR values for mixtures that included different CRCA types with various percentages are higher than the minimum required value of MTO specifications. This indicated a highly successful performance for these mixtures that included CRCA. The results of the ANOVA analysis showed that there is a statistically insignificant effect of CRCA type, and proportion on the TSR. However, the type of CRCA has a higher effect on the results of TSR compared to the CRCA percentage.