This paper describes the initial steps towards the development of a foam concrete-aerogel composite for thermal insulation in lightweight sandwich façade elements. Fire safety is an important issue pertaining insulation materials. Therefore, the need for low-density inorganic, non-flammable materials is rapidly increasing. Foam concrete is a lightweight material with good thermal characteristics; densities as low as 400 kg/m3 and thermal conductivities as low as 100 mW/m·K can easily be achieved. The main advantage when compared to typical inorganic insulations (e.g. autoclaved aerated concrete or mineral wool) is that foam concrete has a much lower embodied energy, in particular due to the simplicity of the manufacturing process. However, in order to be competitive as an effective insulation material, the thermal conductivity needs to be drastically reduced which can be achieved by reducing the density and by incorporating silica aerogels (both measures affecting the compressive strength).

Reference: N. da Silva, U. Mueller, K. Malaga, P. Hallingberg, C. Cederquist, Foam concrete aerogel composite for thermal insulation in lightweight sandwich facade elements, in: Concrete 2015, 2015: pp. 1355–1362.