Rheological properties evolutionary regularities and kinetics of waste PE cracking wax warm-mix asphalt during thermal-oxidative aging

Converting waste plastics into high-value pavement materials has emerged as a crucial pathway for sustainable development. The aging of asphalt binder plays an key role in the performance failure of the pavement. This work investigated the short-term thermal-oxidative aging behavior and the chemical–rheological coupling mechanisms of asphalt modified with polyethylene cracking wax (PEW) derived from waste LLDPE. The DSR (temperature sweep, frequency sweep, MSCR, LAS) and FT-IR spectroscopy tests were conducted to quantify macroscopic rheological changes and microscopic oxidation (I C=O ) of the aging asphalt. An Arrhenius framework was used to extract aging rate constants and activation energies. Pearson correlation/regression analyses established quantitative links between I C=O and key rheological indicators (G*, G*/sinδ, δ, J nr , R, N f ). Results indicate: (1) PEW incorporation elevated asphalt recovery to 58.6%, significantly enhancing high-temperature performance and elastic recovery capacity, yet imparting a “low-strain long-life” fatigue behavior; (2) The aging activation energy (42.63 kJ·mol -1 ) of modified asphalt was significantly higher than that of base asphalt, indicating superior aging resistance potential. However, its polymer network is prone to degradation under high-temperature or deep aging conditions. (3) A strong correlation (R 2 >0.9) exists between the carbonyl index and key rheological indicators, making it an effective predictor of performance. This study offers novel insights for high-value utilization of waste plastics and provides important theoretical guidance for developing environmental friendly road materials.