Synthesis and properties of thermally enhanced aerated geopolymer concrete using form-stable phase change composite

Abstract

Aerated concrete is composed of a large number of air voids to make it lightweight and to improve the insulation capacity; however, it possesses low thermal energy storage capacity. This paper reports the synthesis and properties of phase change material (PCM) composite integrated aerated/foamed geopolymer concrete (GFC) for enhancing the thermal storage capacity. A paraffin/hydrophobic expanded perlite based form-stable PCM composite was incorporated into the aerated concrete, and the chemical compatibility, mechanical properties, and thermal performance were experimentally evaluated. The FT-IR and TGA tests have indicated that the PCM composite is chemically compatible and thermally stable with GFC. The thermal performance tests on GFC, studied by simulated test rooms, has revealed that the GFC containing PCM composite has very high thermal energy storage capacity. The incorporation of 15% and 30% of PCM composite has reduced the peak indoor temperature of the test room by 1.85 °C, 3.76 °C, respectively while enhancing the thermal storage capacity by 105% and 181%. Despite the reduction in mechanical properties of geopolymer concrete with PCM, the GFC containing PCM has shown enhanced mechanical properties. The air-void distribution had also been improved with the formation of uniform and fine air voids in PCM integrated GFC. The enhancement in mechanical properties and uniform distribution of fine air voids was attributed to PCM composite's lightweight properties. This has resulted in reduced foam content to meet density requirements, thus increasing the size of gel particulates surrounding the air voids.