Preparation and optimization of ultra-light and thermal insulative aerogel foam concrete

Lightweight and thermal insulative foam concrete has gathered increasing interests in buildings for energy efficiency. However, their density (∼400 kg/m3) and thermal conductivity (0.10 W/(m·K)) need to be further decreased for high performance applications in green and nearly zero energy buildings. A novel type of aerogel foam concrete with a low density of 198 kg/m3 and thermal conductivity of 0.049 W/(m·K) was successfully fabricated by adding super-insulative and Nano-porous aerogels into micro-porous foam concrete. The microstructure and thermal conductivity of the aerogel foam concrete were experimentally investigated. A model was established for predicting the thermal conductivity of the aerogel foam concrete based on a modified Maxwell model. The calculated results were validated with experimental data, with an error of less than 5%. By using the model, the effects of the ternary ratios on the thermal conductivity were investigated, and the optimization aiming at the minimum thermal conductivity was then implemented. Accordingly, a ternary aerogel foam concrete sample with the optimal ratios was experimentally prepared, whose thermal conductivity and density were approximately 50% lower than those of existing foam concrete. Therefore, the novel type aerogel foam concrete, yielding high performance, could be extensively used for potential applications in green and nearly zero-energy consumption buildings.