Mechanical evaluation and mechanism analysis of the stripping resistance and healing performance of modified asphalt-basalt aggregate combinations

Asphalt modifications can contribute to the moisture susceptibility and fatigue resistance of asphalt mixtures. This study investigated the effects of various asphalt modifications on the bond and healing properties of modified asphalt binders and the mechanism of changes caused by the modification. Five modified asphalt binders were prepared in the laboratory for this study, including SBS-modified asphalt, crumb rubber-modified asphalt, terminal blend (TB) rubberized asphalt, high-density polyethylene (HDPE)-modified asphalt, and gilsonite-modified asphalt. A modified binder bond strength (BBS) test was applied to evaluate the bond and healing performance of five modified binders at both dry and wet conditions. The surface free energy (SFE) test was conducted on the modified binders to investigate the cohesion/adhesion energy variation due to the binder modification. In addition, the ravelling resistance, moisture susceptibility, and fatigue life of the asphalt mixtures prepared using the modified binders and basalt (which is widely used in China) were measured using the Cantabro test, Hamburg wheel-tracking test, and four-point beam fatigue test, respectively. The performance results of the asphalt mixtures are employed to verify the findings of BBS and SFE tests for the modified binders. It is found that the modified BBS test provides a promising tool for evaluating the bond and healing properties of modified asphalt binders, and the SFE could help to explain the mechanism of binder modification. The testing results indicate that gilsonite enhanced the bond strength and surface energy of asphalt, and high-density polyethylene significantly improve the healing performance.