Rejuvenation of aged asphalt using tall oil-based additives: A multi-scale evaluation of diffusion and rheological performance

This study investigates the rejuvenating effects of three crude tall oil-derived products—fatty acids (F), distilled tall oil (T), and rosin (R)—on aged asphalt. The diffusion capacities of the rejuvenators were examined using molecular dynamics simulations and diffusion tests. Thermogravimetric analysis (TGA) and mass loss measurements were conducted to assess their anti-aging properties, while changes in oxygen-containing functional groups before and after rejuvenation were quantitatively analyzed. The macroscopic performance of rejuvenated asphalt was further evaluated through basic physical tests, dynamic shear rheometer (DSR) tests, and bending beam rheometer (BBR) tests. Results show that fatty acids have the highest diffusion capacity and effectively restore the rheological properties of aged asphalt, enhancing low-temperature performance and fatigue resistance but reducing high-temperature rutting resistance and showing weaker anti-aging ability. Rosin improves high-temperature rutting resistance and anti-aging performance but is less effective in restoring low-temperature properties.