Unraveling cooling durability of heat-reflective asphalt thin layers under service-induced physicochemical and structural degradation

Effective pavement cooling mitigates high-temperature distresses in asphalt pavements while reducing heat accumulation and release to the surrounding environment. While reducing solar heat absorption, the cooling effectiveness of conventional heat-reflective coatings often deteriorates rapidly under service conditions. To address these durability limitations, this study systematically evaluates the long-term cooling performance of a previously developed heat-reflective asphalt thin layer material. A high-precision indoor simulated solar radiation apparatus was employed to quantify baseline cooling performance, while durability was assessed under representative conditioning scenarios, including equivalent ultraviolet accelerated aging, accelerated abrasion, dust and oil contamination, and high–low temperature cycling. The results demonstrate that the heat-reflective asphalt thin layer maintains effective cooling performance under multiple degradation factors. After one year of equivalent ultraviolet aging, the surface cooling effect stabilized at 7.6 °C, retaining 87.6% of the initial cooling amplitude with a reduction of only 1.1 °C. Under severe dust contamination, more than 78% of the initial surface cooling effect was preserved, corresponding to cooling magnitudes of 6.8–7.3 °C. Accelerated abrasion induced a gradual, logarithmically decelerating attenuation, with the surface and bottom cooling effects reduced by 36.3% and 38.1%, respectively, after 30,000 cycles, while residual cooling of 6.2 °C at the surface and 3.3 °C at the bottom was maintained. In contrast, transparent oil contamination and repeated high–low temperature cycling exerted minimal influence on cooling performance. Overall, the heat-reflective asphalt thin layer exhibits superior cooling durability under complex service-induced degradation, demonstrating its suitability as a sustainable and cleaner pavement cooling solution.