Study on foam concrete incorporated with expanded vermiculite/capric acid PCM – A novel thermal storage high-performance building material

[Display omitted] •Development of a new phase change material (PCM) which can be incorporated in foam concrete.•The developed foam concrete incorporated with PCM is found to be efficient in thermal insulation in buildings.•The developed PCM incorporated foam concrete takes the advantages of thermal insulation properties of both foam concrete and PCM.•The reduction in strength due to the addition of PCM is overcome by silica fume and coir fibre.•The usage of newly developed PCM can eliminate the artificial heating and cooling in buildings and hence a sustainable solution for thermal comfort in buildings. A major part of energy consumption is reported from the residential and commercial buildings due to the large usage of mechanical devices to maintain a comfortable indoor ambiance. Thermal conductivity of the materials used in these buildings can be reduced by using low density materials and an efficient thermal energystorage strategy. In the present paper, the thermal performance ofa building envelope was improved by incorporating phase change material (PCM) into thefoam concrete mix. At first, PCM was developed by using a light weight material, expanded vermiculite (EV) impregnated with capric acid (CA) and ethyl alcohol (EA) under vacuum conditions. Different foam composite mixes were prepared and experimentally tested. Foam concrete mixtures with EV, CA-EA/EV based PCM, and PCM with added nano silica and coir fiber combinations (PSC) were prepared by the replacement of fine aggregate (M−sand) in various weight percentages. This study reveals that PCM with a CA to EV proportion of 55% (wt.) had the maximum adsorption and stability, as assessed through liquid leakage. In addition to improving thermal efficiency, PCM enhanced foam concrete composites showed improved mechanical, hydration, durability, and thermal characteristics. In comparison to the control foam concrete and PCM foam concrete mixes, the addition of nano silica and coir fiber added foam concrete mixtures (PSC) demonstrated improved strength and shrinkage qualities. These improved properties are attributed to the pozzolanic activity of nano silica and the bridging effects resulting from the fiber to micro cracks. Apart from the durability and strength characteristics, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA) were adopted to characterize the morphological, chemical, and thermal