Preparation and Performance Evaluation of Low-Cost And High-Performance Scrap Sio₂ Aerogel Insulation Mortar (Saim)

Abstract

Insulation materials required for modern buildings need to be able to balance energy consumption, economic cost and environmental sustainability. Silica aerogel (AG)- based insulation mortar is a promising thermal insulation material, but its high production cost limits widespread application in building. This paper addresses the recycling of waste (hydrophilic/hydrophobic aerogel powders and aerogel fiberglass mats) generated in SiO2 aerogel production plants. And the above scrap aerogel (SAG) is used to form a composite insulation aggregate with traditional glazed hollow beads (GHB) for the preparation of scarp aerogel insulation mortar (SAIM). Subsequently, a large amount of experimental work was carried out on the above SAIM, and results demonstrate that hydrophobic SAG create interfacial gaps with cement, achieving superior thermal insulation compared to hydrophilic SAG. In addition, it is shown that the thermal conductivity of SAIM decreases gradually with the increase of composite thermal insulation aggregate content. And when the proportion of hydrophobic aerogel in the composite thermal insulation aggregate is 30%, SAIM has the best thermal insulation performance. This is mainly due to the fact that SAG and GHB show a good gradation in particle size, which in turn forms a reasonable microporous structure characteristic. Based on the above research results, a high performance SAIM with a thermal conductivity of only 0.058 W/(m∙K) was prepared. The mortar meets the requirements of the Type I mortar standard (thermal conductivity less than 0.07 W/(m∙K)). Due to the use of recycled solid waste materials, the cost of SAIM has been reduced by about 85% compared to the cost of the aerogel insulation mortar (AIM).

Keywords: Scrap aerogel, Insulation mortar, Micro-structure, Compressive strength, Thermal conductivity