Evaluation of low temperature performance of oil modified asphalt using the glass transition temperature

As a low-temperature modifier and regenerant, oil has great application potential in cold climate areas with severe thermally induced cracking. To investigate the oil effect on the low temperature performance of asphalt, six different types of oils, including three bio-based oils and three petroleum-based oils were adopted in this study. An approach to determine the glass transition temperature of asphalt binders was proposed using the modified Havriliak-Negami (MHN) complex modulus model. Firstly, the loss modulus master curve was constructed by frequency sweep test to obtain the viscoelastic parameters of MHN model. Then the corresponding frequency when the loss modulus reaches the peak value was obtained. Finally, the glass transition temperature was calculated by Williams-Landel-Ferry (WLF). Moreover, the correlation between the estimated glass transition temperature and the low temperature test results was analyzed. The results showed that the addition of oil significantly improved the low-temperature performance of asphalt, with lower glass transition temperature and downward shifted modulus master curves. The glass transition temperatures of asphalt binders at any reference frequency can be calculated by using the approach proposed in this study. The glass transition temperatures estimated by the approach proposed had an extremely strong correlation with the low-temperature test results of asphalt, and the correlation coefficient with most of the low temperature parameters exceeds 0.9.