Properties of waste vegetable oil recycled asphalt-binder: a molecular simulation study.

The aging of asphalt-binder during long-term use is an important reason for the decline in road performance of asphalt mixtures. In this study, waste vegetable oil (fried for 1-2h) was investigated as a rejuvenator of asphalt-binder. The optimisation effect of waste vegetable oil on the performance of asphalt-binder with different aging degrees (RTFOT, PAV15/20/48h) was evaluated by testing their conventional physical properties, high-temperature properties, and low-temperature properties. The molecular dynamics method was used to construct models, and the diffusion properties, solubility properties, adsorption energy, and asphaltene aggregation were calculated. The influences of linoelaidic acid and oleic acid molecules on aged asphalt-binder molecules were evaluated. The changes in the functional groups of the aged asphalt-binder after the addition of waste vegetable oil were analyzed by infrared spectrometry, and the changes in the microstructure of the aged asphalt-binder surface were observed by scanning electron microscopy. The results revealed that waste vegetable oil could regenerate aged asphalt-binder and significantly improve their physical and high-/low-temperature properties. Waste vegetable oil molecules are compatible with aged asphalt-binder molecules, improve their diffusion behaviour, enhance their adsorption capacity, and slightly reduce the aggregation of asphaltenes. Overall, waste vegetable oil shows great potential for the regeneration of aged asphalt-binder. [ABSTRACT FROM AUTHOR]