Enhancing the thermal properties of foam concrete with pumice-encapsulated soy wax phase change material: a novel approach.

Abstract

This study explored an innovative technique for improving the thermal characteristics of foam concrete by incorporating soy wax phase change material (PCM) encapsulated within pumice. The core of this research is the development of PCM-pumice aggregates through the macro encapsulation of soy wax. This process involves direct impregnation, where melted soy wax is uniformly distributed within the porous structure of lightweight pumice aggregates. The thermal properties of the resulting foam concrete, notably its thermal conductivity, were rigorously evaluated. This evaluation entailed measuring the conductivity using a heat flow meter and subjecting the concrete samples to controlled temperature cycles, with a focus on the 25 °C and 55 °C marks. These specific temperatures were chosen to assess the impact of the PCM phase change on the thermal behavior of the concrete. Key findings indicate that the incorporation of PCM-pumice aggregates markedly improves thermal conductivity and heat retention in the solid state while simultaneously reducing fluidity, density, and compressive strength as a result of increased cohesion and porosity. Thermal conductivity significantly increased by up to 37% in the solid state relative to the control mix, due to the phase change material occupying air gaps within the concrete. Conversely, the thermal conductivity decreased in the liquid state, utilizing the PCM's latent heat capacity to lower heat transfer rates.