Fly ash based lightweight wall materials incorporating expanded perlite/SiO₂ aerogel composite : Towards low thermal conductivity

Fly ash based lightweight wall materials (LWM) incorporating expanded perlite (EP)/SiO₂ aerogel composite were successfully prepared towards low thermal conductivity. As a functional padding, silica aerogel with density of 119 kg/m³ and thermal conductivity of 0.0277 W/(m·K) was synthesized by a two-step catalytic method and drying procedures under mild conditions. EP/SiO₂ aerogel composite was further synthesized via impregnation method to load the SiO₂ aerogel on the surface of EP. The bulk density and compressive strength of the prepared fly ash based LWM incorporating the optimized 20% EP/SiO₂ aerogel composite reached 335 kg/m³ and 0.88 MPa, respectively, and the thermal conductivity was significantly reduced to 0.050 W/(m·K). Hence, the fly ash based LWM consisting of EP/SiO₂ aerogel composite could be efficiently useful as building insulation thermal materials.