Preparation and characterization of silica aerogel foam concrete: Effects of particle size and content

In order to study the effect pattern of hydrophobic silica aerogel on aerogel foam concrete (AFC), this work successfully prepared silica aerogel foam concrete (AFC) and investigated the influence of the silica aerogel (SA) particle size and content on the properties of AFCs in detail. The microstructure shows that the SAs are inlaid in the foam concrete matrix, forming a physical combination between the two components. Due to the hydrophobic property of SA, its incorporation into AFCs significantly alters the physical and chemical properties of the material. Notably, the primary impact lies in the remarkable antifoaming effect imparted by hydrophobic SA, a phenomenon regulated by both the content and particle size of SA. Furthermore, the introduction of SA imparts hydrophobic characteristics to the prepared AFCs, with enhanced hydrophobicity observed at higher SA content and smaller particle sizes. The study outcomes reveal that the density, compressive strength, and thermal conductivity of AFCs are influenced by the defoaming effect of SA. Specifically, a decrease in particle size of SA correlates with increased density and compressive strength in AFCs, primarily attributed to the defoaming effect of SA influencing the pore structure of the material. Simultaneously, the thermal conductivity of AFCs falls within the range of 59.0–83.5 mW/m/K, a metric affected by both the SA content and the concurrent defoaming effect. By investigating the influences of silica aerogel particle size and content, this work contributes some novel insights into optimizing the comprehensive performance of AFCs, which is conducive to the development of aerogel composites.