Investigation of rheological and chemical properties asphalt binder rejuvenated with waste vegetable oil

To improve the performance of asphalt mixture with high content of reclaimed asphalt pavement (RAP), rejuvenator is usually added. The traditional rejuvenator is non-renewable and contains large amount of carcinogenic polycyclic aromatic hydrocarbons. In this study, the effects of waste vegetable oil (W-oil) on rejuvenating aged asphalt binder were investigated in terms of rheological and chemical properties. The viscosity, complex shear modulus, and fatigue life were measured using Rotational Viscometer (RV) and Dynamic Shear Rheometer (DSR). The chemical properties were characterized by Gel Permeation Chromatography (GPC) and Fourier Transform Infrared Spectroscopy (FTIR). The experimental results indicated that the workability and fatigue resistance of aged asphalt were improved by addition of W-oil. The logarithm values of viscosity of rejuvenated asphalt at specific temperature showed linear relationship with the dosage of W-oil. The fatigue life of rejuvenated asphalt increased exponentially as the dosage of W-oil increased. There was no chemical reaction found between W-oil and aged asphalt. With the increasing content of W-oil, sulfoxide index (ISO) and the large molecule size (LMS) content decreased due to physical dilution. Besides, the workability and fatigue resistance of rejuvenated asphalt were found having close correlations with sulfoxide index and the LMS content.