Effects of rheology and adhesiveness of asphalt binders to different substrates on the resistance to moisture conditioning

Adhesiveness is a property that directly affects the service life of asphalt pavements. Over the years, different materials, research methods and tests have been used to investigate different adhesiveness aspects of materials. This paper investigated two asphalt binders, one with and one without amine-based anti-stripping agent, as well as two aggregate sources. The objective was to investigate the effects of rheology (stiffness and rutting) of the asphalt binder and adhesiveness of asphalt binders to different substrates on the resistance to moisture conditioning. The results indicated that moisture conditioning reduced the average stiffness of the binders by about 15% for both binders. The addition of amine-based anti-stripping agent reduced the stiffness of the neat binder by approximately 9%, and at 82°C the neat binder presented higher rutting resistance if compared to the modified binder using anti-stripping agent. The aggregate area within the HMAs in contact with asphalt binder did not show a good correlation with the pull-off tensile strength in the dry condition, but it presented good correlation after moisture conditioning. This suggests that adhesion force itself may not be greatly affected by the proper contact between aggregate and binder, but such contact does help preventing moisture damage in the interface.