To address the growing demand for sustainable road infrastructure development andresolve technical bottlenecks in reclaimed asphalt pavement (RAP) recycling, this studyoptimized the performance of recycled asphalt mixtures (RAMs) and validated their engineeringapplicability for field construction. RAM specimens were prepared using 5-yearand 10-year aged RAP from Ningxia, with a constant RAP content of 30%. Laboratorytests including high-temperature rutting, moisture susceptibility, low-temperature cracking,dynamic modulus, and four-point bending fatigue were performed to determine theoptimal mix proportion. Fourier Transform Infrared Spectroscopy (FTIR) and Thin-LayerChromatography-Flame Ionization Detection (TLC-FID) were employed to reveal the regenerationmechanism of waste engine oil (WEO). Results showed that WEO modified thefunctional groups and four fractions of asphalt, optimizing its colloidal structure, whileexcessive WEO compromised high-temperature stability. The optimal WEO contents were4% for RAP (5Y) and 8% for RAP (10Y), which significantly enhanced the overall performanceof RAM to adapt to Ningxia’s climate. This study provides technical support forsustainable road infrastructure in arid and semi-arid regions.
Men et al. (2026) studied this question.