Moisture damage refers to the reduction in stiffness and strength in asphalt mixtures due to moisture exposure, compounded by the mechanical stress from traffic load, leading to a condition commonly known as stripping. Moisture damage, which causes a decline in the structural integrity of asphalt pavement, is a major factor in the emergence of various types of distress such as fatigue cracking, rutting, and more. Hence, the objective of this research is to assess the impact of different binder types and treatment methods of Coarse Recycled Concrete Aggregate (CRCA) on the tensile strength and moisture resistance of Hot Mix Asphalt (HMA) of Ontario Superpave mixtures. This study employs two kinds of binders: PG 64-28 and PG 52-34. Thermal treatment method, accompanied by short mechanical treatment, were carried out to improve the CRCA properties. Two different types of binders, 0.0% and 30% CRCA, were used to conduct mix designs of asphalt mixtures. At a 30% CRCA level, the emphasis was on evaluating the impact of binder types and treatment techniques. The tensile strength and moisture sensitivity of the asphalt mixtures were assessed in relation to the binder types and treated CRCA. The study found that when compared to the typical control mix, HMA mixtures with different types of binder combined with treated CRCA showed higher tensile strength. Additionally, the laboratory analysis showed that all TSR values for mixtures containing various binder types with CRCA treatment are higher than the MTO specifications’ minimum demand value, except the control mixture containing PG 52-34. Furthermore, the outcomes demonstrated that mixes containing treated CRCA, and the PG 64-28 binder type had greater Tensile Strength Ratio (TSR) and Indirect Tensile Strength (ITS) than mixes containing the PG 52-34 binder type. These findings suggest that mixtures containing CRCA performed exceptionally well. The ANOVA analysis outcomes indicated that the type of binder has a higher impact on ITS and moisture susceptibility outcomes than treating CRCA. Furthermore, because of their negligible interaction, these parameters function independently of one another.
Key words: Asphalt mixtures, Coarse recycled concrete aggregate (CRCA), Moisture damage, Tensile strength, treatment methods.
