Study on the influence of aerogel on the performance of cement‐based composites at room temperature and after high temperature

This study investigates the physical and mechanical properties of SiO 2 aerogel–powder cement‐based composites (ACC) at room temperature and after high‐temperature exposure. The thermal conductivity, pore structure, and mechanical properties of the ACC were characterized using thermal conductivity testing, N 2 adsorption–desorption analysis, four‐point bending and compression tests, and scanning electron microscopy (SEM). Preliminary empirical relationships were established among room‐temperature compressive strength, porosity, and aerogel content. As the aerogel content increased from 0% to 50%, the density decreased from 2.15 to 1.74 g/cm 3 , and the thermal conductivity dropped from 0.57 to 0.35 W/(m K). BET analysis revealed that pores were primarily concentrated in the 3–5 nm range and increased in volume with higher aerogel content. After exposure to 600°C, the residual flexural and compressive strengths were approximately 25% and 30% of their room‐temperature values, respectively; residual strengths were higher following natural cooling compared to water cooling. The ACC developed in this study offers a load‐bearing material option with low thermal conductivity for building envelope insulation and fire‐resistant linings.