Study on Freeze–Thaw Cycle Performance and Regional Service Life Prediction of Hydrophobic Aerogel-Modified ACEPS Boards

The aim of this study is to systematically investigate the influence of hydrophobic aerogel on the performance of aerogel cement-based expanded polystyrene (EPS) insulation board (ACEPS board) under freeze-thaw cycles (FTCs) and to predict its service life in four typical climate zones: Beijing, Harbin, Urumqi, and Nanjing. The effects of aerogel content on compressive strength, volumetric water absorption, thermal conductivity, and pore structure evolution of ACEPS were thoroughly analyzed through FTC testing. The results demonstrated that aerogel significantly reduced the volumetric water absorption of ACEPS due to its excellent hydrophobicity, thereby decreasing the compressive strength attenuation from 40% to 24%, suppressing the increase in thermal conductivity from 0.0130 to 0.0055 W/(m·K), and mitigating pore structure degradation. In the regional service life prediction, aerogel-modified ACEPS exhibited significantly improved freeze-thaw resistance in the cold climates of Harbin and Urumqi, as well as in the high freeze-thaw frequency environment of Beijing. Notably, specimens with high aerogel content demonstrated outstanding structural and functional durability. This study provides a theoretical foundation and practical guidance for incorporating aerogel in the optimized designs and applications of thermal insulation building materials in cold regions.