Asphalt Pavement Design and Durability Under CMIP6 Warming in China

Climate warming can alter asphalt pavement design requirements and durability. WorldClim 2.1 and eight CMIP6 models provided common climate inputs for comparing representative semi-rigid and flexible base pavements across China. Three future periods under SSP2-4.5 and SSP5-8.5 were evaluated against the 1970–2000 baseline. JTG D50-2017 relationships combined climatic inputs with equivalent layer thicknesses and moduli to calculate temperature adjustment factors and equivalent temperatures. With other design inputs fixed for each structure, temperature-dependent performance relationships quantified relative changes in allowable load repetitions, allowable subgrade strain, and asphalt-layer permanent deformation separately for each climate model. National area-weighted and nine-city results were summarized using ensemble medians and interquartile ranges. For 2021–2040, the ensemble medians of national warming were 1.64 °C and 1.85 °C under SSP2-4.5 and SSP5-8.5, respectively. Under SSP5-8.5, the ensemble medians of national mean reductions in asphalt-layer allowable load repetitions increased from 4.10% and 6.86% in 2021–2040 to 11.84% and 19.25% in 2081–2100 for semi-rigid and flexible base pavements, respectively. Late-century national warming under this scenario ranged from 4.23 to 8.20 °C across models. The ratio of flexible to semi-rigid asphalt-layer temperature factor increments was 2.35, based on ensemble medians of national means, with larger increments for flexible pavements in all eight models. These findings support updating local temperature inputs and comparing candidate structures through fatigue, subgrade strain, and rutting checks matched to project design periods.