Performance responses of SBS-modified asphalt with varying dosages under ultrasonic stirring conditions

Ultrasonic cavitation and mechanical vibration promote the homogenisation, dispersion, and swelling of SBS in asphalt, making ultrasonication an effective auxiliary method for preparing SBS-modified asphalt. However, intense ultrasonic energy may cause mild thermal and mechanical degradation of asphalt components, leading to dosage-dependent changes in the rheological and chemical properties of SBS-modified asphalt. In this study, a self-developed ultrasonic device was used to treat SBS-modified asphalt, and its performance responses at different dosages were systematically evaluated in terms of compatibility, rheological behavior, deformation resistance, fatigue, low-temperature relaxation, and aging characteristics in detail. Results showed that ultrasonication enabled more SBS particles to melt into the asphalt, significantly improving modifier-asphalt compatibility. It also enhanced the elastic characteristics of the modified asphalt and improved rutting deformation recovery, fatigue resistance, and low-temperature stress relaxation. Furthermore, ultrasonic treatment improved the short-term aging resistance of asphalt but reduced its long-term aging resistance.