Coupled effects of fuel corrosion and photothermal aging on asphalt binder degradation for airport pavements

Airport pavements face combined threats from photothermal aging and aviation fuel spillage, yet their synergistic degradation mechanisms are not fully elucidated. This study evaluates asphalt binder performance under coupled damage, revealing a distinct two-stage degradation pattern. Results indicate that initial aging induces a colloidal structural imbalance, which facilitates the subsequent leaching of critical chemical fractions by aviation fuel. Fourier Transform Infrared Spectroscopy analysis of contaminated fuel directly confirms this sequential extraction, where sulfoxides and aromatic components generated during prior oxidation are aggressively leached from the binder matrix. This synergistic depletion markedly increases the Glover–Rowe parameter, reaching up to 68.4 kPa under coupled thermal–fuel conditions, together with a substantial reduction in fatigue life exceeding 93%. Furthermore, the irreversible washout of active functional groups from the matrix diminishes the inherent bonding capacity, resulting in an average 24.1% reduction in asphalt–aggregate adhesion across the two aggregate types. Rubberized asphalt exhibited enhanced overall resistance, reflected by a lower normalized comprehensive degradation area than the other two binders, possibly owing to antioxidant effects and swelling-induced light-component retention. However, this enhancement weakened under thermal–fuel exposure, with the largest additional light-component loss and complex modulus reduction. These findings provide a theoretical foundation for designing highly durable, fuel-resistant airport pavement materials.