Composition Design of Waste Vegetable Oil-Based Rejuvenator Based on RSM and Performance Evaluation of Rejuvenated Asphalt

In order to develop an environment-friendly asphalt rejuvenator, waste vegetable oil (WVO) was selected as the base oil. The composition of the rejuvenator was first designed based on the response surface methodology (RSM), and 16 groups of rejuvenator samples were obtained. Then, these samples were used to regenerate aged asphalt and 16 groups of rejuvenated asphalt samples were prepared. Afterward, the viscous, conventional, rheological, and fatigue resistance properties of these rejuvenated asphalts were measured and evaluated, and the optimal composition of rejuvenator was determined. Results show that the addition of WVO-based rejuvenator can reduce the viscosity and softening point of aged asphalt, increase its penetration and ductility, and restore the physical properties and viscosity of aged asphalt to that of original asphalt. With the addition of WVO-based rejuvenator, the high-temperature performance of aged asphalt gradually declined, but the rejuvenator with optimal composition can restore its high-temperature performance to the similar level as original asphalt. The addition of WVO-based rejuvenator can evidently improve the fatigue damage resistance and low-temperature cracking resistance of aged asphalt, achieving a good regeneration effect. The fitting equation based on RSM can achieve an accurate and reliable prediction on the viscous, conventional, rheological, and fatigue damage properties of rejuvenated asphalt. According to the results of model optimization, the optimal composition of WVO-based rejuvenator is recommended as WVO:Dibutyl phthalate (DBP):antiaging agent (AA) = 90:9:1.