Phase change material coated geotextile for temperature regulation of subgrade soil

Abstract

High temperatures leading to thaw settlement deformation of soil are the primary cause of damage to road structures in permafrost regions. In this study, phase change material (PCM) is prepared by adsorbing tetradecane, and epoxy resin composite phase change material (ERPCM) is prepared by combining epoxy resin with PCM. ERPCM is applied to geotextile to create phase change geotextile (PCG) with energy storage and impermeability characteristics. The impact of epoxy resin content and freeze–thaw cycles on ERPCM performance is analyzed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The results show that epoxy resin enhances the thermal stability and freeze–thaw resistance of ERPCM. When the mass ratio of epoxy resin to PCM is 0.8:1, ERPCM exhibits its highest enthalpy values both before and after freeze–thaw cycles, reaching 81.5 J/g and 72.6 J/g, respectively. The energy storage modulus of ERPCM decreases with increasing epoxy resin content. Temperature regulation experiments demonstrate that PCG under different structures can adjust the sample temperature within the range of 6 to 16 °C. Higher quantities of ERPCM could store more energy in the PCG. The temperature regulation effect is more pronounced when PCG is placed at greater depths. Increasing the number of PCGs improves the overall temperature regulation effect but reduces the individual temperature regulation effect of each PCG. This study has theoretical significance and practical value for promoting the further application of PCM in permafrost subgrades.