Title : The application and impact of aerogels in mineralized foams
Abstract:
As a type of building material, foamed concrete is often used in various situations as a material that simultaneously offers certain load-bearing capabilities and thermal insulation performance. Numerous studies have shown that the strength and thermal conductivity of foamed concrete decrease as the material’s density decreases. Mineralized foam, as a category of foamed concrete, is primarily envisioned for applications such as insulation layers or as infill material within prefabricated structures. In such applications, the structural strength can be supplemented through mutual support among materials, allowing the density of mineralized foam to be further reduced to achieve better thermal insulation performance. In pursuing enhanced insulation, innovative aerogel particles could be considered as an additive to the mineralized foam mix, attempting to combine the advantages of both materials.
However, during the actual experiments, incorporating aerogel particles into mineralized foam proved to be highly challenging. For instance, the hydrophobic nature of the particles led to damage in the foam structure. Additionally, the increased viscosity of the cement mixture caused by the addition of particles amplified the impact of environmental factors during the material preparation process.
In the experiments, the effects of introducing aerogel particles at different stages of mineralized foam preparation were investigated. An innovative approach was proposed to pre-coat the aerogel particles with cement paste to mitigate foam structure damage caused by the hydrophobic properties of the particles. The study also tested the impact of particle size on the final material properties. By grinding the aerogel particles to reduce their size and increase their surface area, a fine, dust-like aerogel material was obtained. By comparing mineralized foam produced with intact particles and ground particles, it was partially confirmed that the current mixing techniques are not suitable for such tests. Furthermore, the experiments identified potential types of mixers that may be appropriate for coating the aerogel particles.
The experiments also confirmed that, as expected, the thermal insulation performance of the mineralized foam improved with the addition of aerogel. However, the compressive strength of the material did not align entirely with initial expectations. Since aerogel particles do not participate in the hydration reaction of cement, they theoretically should not enhance the compressive strength of the material. Moreover, as the aerogel content increases, the strength of the material is expected to decrease. Yet, under different viscosity conditions, an increase in material strength was observed with higher aerogel content. This phenomenon is likely the result of the combined effects of slurry viscosity and the foam structure damage induced by the aerogel.
