Effects of polymer structure on the physicochemical and performance-related properties of SBS-modified asphalt binders subjected to short-term aging

This study aims to investigate the effects of styrene-butadiene-styrene (SBS) polymer structure on the physicochemical and performance-related properties of modified asphalt binders, with the consideration of two other influencing factors: polymer content and aging condition. The factorial experimental design involves three types of SBS polymers (diblock, linear triblock and radial), two polymer content (3% and 6%), and four aging conditions. The results indicate that binder properties are influenced by both the main effects and interaction effects of the three factors. Polymer structure is a predominant factor affecting polymer particle morphologies in the modified binders and storage stability. Polymer content is the leading factor for the polymeric characteristic peaks in infrared spectrum, elasticity, elastic recovery, and non-recoverable creep compliance of the binders, while aging condition contributes to the majority of variations in binder oxidization and complex shear modulus. From the perspective of engineering application, the effects of polymer structure are limited at low polymer content, while more significant property differences are observed at high polymer content. To fully take the advantages of SBS polymer modification, the joint influences of polymer structure, content, and aging must be considered. The findings are expected to assist in material design, construction process control, and quality assurance testing of SBS-modified asphalt.