Effect of bio-based and refined waste oil modifiers on low temperature performance of asphalt binders

• Stiffness master curve of oil modified asphalt is shifted to lower level.
• Oil can increase the fracture energy of asphalt significantly.
• Tg decreased after introducing oil into asphalt.
• Fracture temperature of oil modified asphalt mixture is much lower.

Thermally induced cracking of asphalt pavement continues to be a serious issue in cold climate regions. As a modifier, oil can be used to improve the low temperature performance of asphalt binders because of lower stiffness and more rapid stress relaxation when added to asphalts. To investigate the oil effect on the low temperature performance of asphalt, different oils, including bio-based and refined waste oil are used in this study, and Bending Beam Rheometer (BBR) test, Single Edge Notched Beam (SENB) test and Modulated Differential Scanning Calorimetry (MDSC) test are employed to evaluate the effect of oil on low temperature performance of asphalt. It is found that the stiffness of asphalt decreased, m-value of asphalt increased, the fracture energy of asphalt increased and glass transition temperature (Tg) becomes lower after adding these oils. This means that these oils can improve the low temperature performance of asphalt. And in addition, Thermal Stress Restrained Specimen Test (TSRST) of asphalt mixture is used to verify the conclusion. The TSRST results show that the fracture temperature of oil modified asphalt mixture is much lower than neat asphalt mixture, which proves the conclusions of the advantages of oils used.