Towards an energy efficient cement composite incorporating silica aerogel: A state of the art review

Abstract

Silica aerogel is a nano-porous material with remarkable insulation properties. Because of this, it can be an ideal alternative to traditional thermal insulating building materials which can promote energy efficiency in buildings. Consequently, it is gaining more interest in the construction industry and now many researchers have carried out investigations on incorporating silica aerogel in cement composite. Currently, most of these studies focused on the thermal conductivity and compressive strength of the cement composite. Therefore, this paper reviews the prior development and current findings of silica aerogel incorporated cement composite in promoting such an energy efficient building material. The effect of different forms of silica aerogel on the physical and mechanical properties of cement composite is discussed. In general, silica aerogel incorporation in any form (cement/sand replacement or as additive) tends to improve the thermal insulation (up to 0.02 W/m.K) of cement composite, whereas the density and mechanical strengths tend to reduce substantially (up to 90%). Furthermore, with the incorporation of silica aerogel, the porosity and water absorption of cement composite increased up to 3 times. Finally, this paper also describes the limitation of silica aerogel incorporation in cement composite. In addition, it highlights the future studies required to promote the adoption of such sustainable energy efficient buildings material on a larger scale.