Multi-scale evaluation on the adhesion performance of SBS modified asphalt binder adding new compatibilizers

The bonding performance between styrene-butadiene-styrene (SBS) modified asphalt binder and aggregates directly affects pavement performance and durability. Although studies have shown that compatibilizers can improve the compatibility and low-temperature performance of SBS modified asphalt binder, research on their impact on adhesion performance remains insufficient. In this study, an optimal formulation of a novel three-component compatibilizer was innovatively designed using the simplex centroid method. A multi-scale research approach was employed to evaluate the adhesion performance of SBS modified asphalt binder (SBSMA) and SBS modified asphalt binder incorporating a self-developed compatibilizer (SBSMA-C), with an analysis of the correlations between them. The results indicate that the optimal compatibilizer formulation is a mixture of rubber oil, oil slurry-extracted oil, and plasticizer in a mass ratio of 64:31:5, attributed to the synergistic effect of multiple components. In the unaged state, the compatibilizer enhances the mechanical interlocking and chemical adsorption between SBS and aggregates, resulting in a 32.2 % increase in the pull-off strength of SBSMA-C compared to SBSMA. Additionally, the work of cohesion, work of adhesion, and work of de-bonding of SBSMA-C increase significantly; however, the work of de-bonding gradually decreases with aging, demonstrating superior resistance to water damage. The compatibilizer supplements light components, leading to a more uniform distribution of bee structures in the aged SBS modified asphalt binder and increased micro-surface fluctuations. Furthermore, correlation analysis shows that although the correlation coefficients between pull-off strength and work of adhesion, as well as work of cohesion, are slightly lower for SBSMA-C than for SBSMA, strong correlations still exist. These findings offer a new strategy for improving the adhesion performance of SBS modified asphalt binder, with practical implications for enhancing pavement durability and reducing maintenance costs. • Adhesion performance of SBSMA and SBSMA-C was studied through multi-scale. • Self-developed compatibilizer was designed using the simplex centroid method. • Work of de-bonding between SBSMA-C and aggregates is reduced by aging. • Pull-off strength strongly correlates with the work of adhesion and cohesion.