Effect of SiO₂ aerogel and perlite on properties of foamed concrete

To enhance the insulation performance, strength, and fire resistance performance of foamed concrete, this paper investigates the effects of incorporating nano-silica aerogel and expanded perlite. A comprehensive comparison and analysis were conducted on the dry density, water absorption, mechanical performance, thermal conductivity, fire-resistant insulation, and microstructure of both Nano-SiO₂ Aerogel Foamed Concrete (NSAFC) and Expanded Perlite Foamed Concrete (EPFC). The findings indicate that as the Nano-SiO₂ Aerogel (NSA) content increases, the water absorption of the foamed concrete gradually rises. Conversely, the water absorption of the foamed concrete test blocks first increases and then decreases with an increase in Expanded Perlite (EP) content. It is noteworthy that, incorporating 10% NSA and EP reduces the dry density of foamed concrete by 12.7% and 7.8%, respectively. When EP content reaches 6%, the 28-d flexural and compressive strengths of the foamed concrete test blocks increase by 73.5% and 54.2%, respectively. Similarly, at NSA content of 6%, the 28-d flexural and compressive strengths increase by 70.5% and 39.6%, respectively. The fire-resistant insulation tests demonstrate that NSAFC exhibits superior thermal insulation and fire resistance performance compared to EPFC. Furthermore, SEM images demonstrate that the pore structure of NSAFC is more uniform.