Eco-friendly building materials containing micronized expanded vermiculite and phase change material for solar based thermo-regulation applications

Phase change materials (PCMs) have been widely studied to decrease energy consumption and dependency on fossil fuels that causes environmental concerns, and improve building energy efficiency. In this regard, this study aimed to fabricate structural cement based mortar with indoor thermo-regulation function utilizing form stable PCM (FSPCM). FSPCM was made of micronized expanded vermiculite (MEV) impregnated with Lauric-Myristic acid eutectic mixture (LA-MA). The facile direct impregnation method was used for the production of the FSPCM. The cement-based mortars were then manufactured by replacing the FSPCM with sand at 15%, 30% and 45 wt% ratios. The basic properties of the manufactured cement-based mortars such as physical, mechanical, thermal conductivity, thermal energy storage and thermoregulation performance were systematically investigated. With the incorporation of 45% FSPCM, thermal conductivity (0.42 W/mK), bulk density (1239 kg/m³) and compressive strength (56.2 MPa) decreased by 60.93%, 39.2% and 85.94%, respectively. In terms of compressive strength, all samples with FSPCM can meet the standard requirements. Differential Scanning Calorimetry (DSC) analysis revealed that the melting temperature and latent heat of FSPCM and FSPCM-included cement mortar (45 wt%) are 32.16 °C and 73.70 J/g and 31.96 °C and 18.90 J/g, respectively. The thermoregulation performance test indicated that the produced FSPCM-included cement based mortars are able to provide thermal comfort by minimizing indoor temperature fluctuations and thus saving energy by reducing heating-cooling loads in buildings.