Experimental investigation on thermal conductivity of aerogel-incorporated concrete under various hygrothermal environment

Since aerogels have low density and thermal conductivity, mixing aerogels with concrete can effectively improve the thermal insulation of concrete materials. In this study, aerogel-incorporated concrete (AIC) with different aerogel volume admixtures were prepared. The porosity and pore distribution characteristics of AICs were obtained using scanning electron microscope and microparticle mercury porosimeter. The variation of thermal conductivity with temperature (20–90 °C) under dry state and the effect of humidity (35 °C, 0–100% relative humidity) on the thermal conductivity of AICs were studied experimentally. Meanwhile, the water absorption coefficient and sorption isotherms were obtained. The results show that the thermal conductivity of AIC changes with the content of aerogel following a quadratic function. The highest reduction in thermal conductivity was 79.3% with the increase in the content of aerogel. Within the temperature range of 20–90 °C, the thermal conductivity of AIC increases with the increase in temperature. The highest increase in thermal conductivity was 15.5%. The change in thermal conductivity with humidity can be fitted to a cubic polynomial function. When the relative humidity changes from 0% to 100%, the variation in thermal conductivity of AIC0 is the lowest (19.51%). Additionally, the corresponding highest variation in the thermal conductivity was observed for AIC60 (76.33%).