On the enhanced properties of composite asphalt via adding surface modified calcium sulfate whisker-SBR

• Surface modification of calcium sulfate whiskers with stearic acid and titanate coupling agent enhances compatibility with asphalt, improving dispersion and mechanical properties. • Optimal MCSW loading of 4% increases the performance grade (PG) of SBR-modified asphalt from 64 to 70, significantly boosting high-temperature performance. • MCSW-SBRMA exhibits excellent low-temperature ductility (>100 cm at 5°C), addressing cold-weather cracking issues. • Microscopic and spectroscopic analyses confirm uniform dispersion of MCSW in asphalt, facilitating shear stress dispersion and enhancing durability.