Development and Evaluation of the Hard-Grade Asphalt

Increasing dynamic shear modulus of asphalt binder is one effective measure of improving modulus of asphalt mixture at high temperature. Dynamic shear modulus of asphalt binder may improve through modifying asphalt with polymer or decreasing asphalt grade. In this study, the solvent deasphalting art of producing the hard-grade asphalt demanded crude oil of high quality and decreased the performance of asphalt at low temperature, adopting the technology of blending the hard modifier with the high-grade asphalt reached the criteria of defining the hard-grade asphalt, i.e., dynamic shear modulus is over 10 kPa at the temperature of $60°\text{C}$ (10 rad/s), phase angle is less than 70°, and performance grade achieves 76-22. The results of mix performance tests indicated that the dynamic modulus of the mixture with the hard-grade asphalt at high temperature increased significantly, the antirutting ability also improved notably, while the bending resistant ability at low temperature and the antifatigue ability were slightly inferior to those mixes with the styrene butadiene styrene modified asphalt (PG70-28).