A novel building material with low thermal conductivity: Rapid synthesis of foam concrete reinforced silica aerogel and energy performance simulation

With the increasing number of commercial buildings in the United States, the energy consumption for space air conditioning is continuously rising. Considering the external building envelope an important role to generate cooling and heating loads, we developed a new high performance building material for building envelope application. Hence, a novel foam concrete reinforced SiO₂ aerogel (FC-SA) material was synthesized via sol-gel technique, vacuum impregnation method and rapid supercritical drying process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric / differential scanning calorimetry (TG-DSC), N₂ adsorption-desorption test (BET) and transient plane source method (TPS). The prepared composite had a high degree of aerogel filling (74% volume of matrix) and the aerogel component still maintained a porous nanostructure. Besides, FC-SA showed a large specific surface area of 405.3 m²/g and high pore volume of 1.28 cm³/g. Meanwhile, the introduction of aerogel has little effect on the mechanical strength of the matrix material. According to the test results, the thermal insulation performance of foam concrete has been found greatly improved with silica aerogel composition. The thermal conductivity of FC-SA composite was measured as low as 0.049 W m⁻¹ K⁻¹ at room temperature (30 °C), which was a 48.4% decrease from foam concrete. Finally, the energy saving simulation results showed that in cold and hot areas, the use of FC-SA to replace traditional concrete materials can greatly reduce both of energy consumption and cooling water consumption.