Mitigating Freeze–Thaw Damage in Soils via Phase Change Materials

Freeze–thaw (F-T) cycles cause substantial deterioration in pavement systems due to frost heaving and thaw settlement in cold regions. This study investigates using phase change materials (PCMs) to mitigate F-T-induced damage in frost-susceptible subgrade soils. PCMs store and release latent heat during phase transitions, reducing temperature fluctuations near freezing and limiting ice lens formation. Three PCM types were initially screened based on thermal behavior and compatibility with two soil types: glacial till (GT) and sandy soil (SS). These were (1) an inorganic salt-hydrate solution (PCM-A), (2) a liquid organic PCM (PCM-B), and (3) a powdered form of PCM-B (pPCM-B). PCM-B was selected for further evaluation. Resilient modulus (MR) and frost heave–thaw settlement tests assessed its performance under repeated F-T cycling. Results showed that 10% PCM-B reduced frost penetration and frost heave by 50% and 85%, respectively. During testing, PCM-treated specimens maintained 10% moisture content, while controls reached 35%, indicating reduced water intake. PCM-B-treated soils preserved MR values after 0, 2, and 5 F-T cycles, showing no mechanical degradation. Improvements were attributed to PCM-B’s thermoregulation and influence on permeability, which together limit moisture migration and ice lens formation. These findings demonstrate PCM-B’s potential to enhance F-T resistance in subgrade soils without compromising mechanical stability.