Physical, chemical, and thermal properties of porous expanded perlite-based phase change composite and their effects on the hydration kinetics

Phase change materials (PCMs) play a pivotal role in storing renewable thermal energy and are extensively utilized in construction and temperature regulation systems. The process of selecting or developing a suitable PCM necessitates diligent consideration of numerous physical and chemical properties. Therefore, this study has been focused on the environmental and sustainability aspects of PCM usage, with a specific emphasis on phase change materials utilizing porous expanded perlite (EP). Shape-stabilized composite PCMs are synthesized by impregnating stearic acid (SA) into the highly porous matrices of EP. The composite nature of the synthesized samples and the chemical compatibility of the constituents are verified by FTIR and XRD. The melting and solidification temperatures of the samples are in the ranges of 69.52-71.96 ℃ and 64.45-66.21 ℃, with the highest respective enthalpies being 85.46 and 85.10 J/g. Superior thermal stability against temperature fluctuations is observed for the synthesized composite PCMs, validated through TGA and leakage tests. Synthesized samples exhibit congruencies in heat charging and discharging even after 150 cycles of heating and cooling. Moreover, the addition of 10% EPSA composites into cement paste achieves a substantial reduction (~12%) in the heat of hydration in the cementitious system. These findings highlight the potential of these composite PCMs to be used in concrete to mitigate crack formation and defects caused by internal stress and the evolution of high heat during mass concrete production, emphasizing their significance in sustainable construction practices.