Study on preparation and performance of advanced aerogel foamed concrete with ultra-light aerogel

Abstract

Aerogel foamed concrete has been acknowledged as one of the most promising energy efficient building materials with high thermal insulation performance and low density in applications of green buildings and nearly zero energy buildings. However, the practical economy of aerogel foamed concrete is still relatively poor because of the greater amount of high-price ultra-insulating aerogel additive needed in the foamed concrete. Therefore, based on the premise of maintaining the high thermal insulation performance and low density of foamed concrete, reducing the amount of aerogel additive has become a key issue to improve the economy and promote the application of high-performance aerogel foamed concrete. This study proposed an equal volume replacement method based on using an ultra-light SiO2 aerogel instead of conventional SiO2 aerogel to reduce the amount of aerogel additive in foamed concrete while maintaining a high thermal insulation performance and low density. Two kinds of aerogel foamed concrete were prepared by filling light density (170 kg/m3) and ultra-light density (75 kg/m3) adiabatic aerogel powder into foamed concrete. An experiment was conducted to study the influence of different aerogel densities on the thermal conductivity, compressive strength and density of foamed concrete. The research results indicate that the density and thermal conductivity can be effectively reduced by filling ultra-light aerogel powder compared with traditional aerogel foamed concrete with an acceptable compressive strength. The results also show that the mass dosage of aerogel can be significantly reduced by using ultra-light aerogel powder. Specifically, for a foam volume ratio of 70 % and aerogel volume ratio of 13 %, the density and thermal conductivity of the ultra-light aerogel foamed concrete were reduced by approximately 10 %, which resulted in a cost reduction of 49 %. By applying the ultra-light aerogel foamed concrete in the construction of an exterior wall of a building, the heat loss through the wall can be reduced by 9 %. This study provides a significant reference for the preparation of high-performance foamed concrete and accelerates the application of super adiabatic aerogels in the building energy conservation industry.