Inorganic foams made from alkali-activated fly ash: Mechanical, chemical and physical properties

Alkali-activation of fly ash together with an aluminum powder blowing agent led to the synthesis of inorganic fly ash-based foam (FAF). The FAF is characterized by means of its compressive and flexural strength, thermal conductivity and capacity, exposure to high temperatures, performance in chemically aggressive environments, and 2D morphology. In comparison to traditional autoclaved aerated C-S-H-based materials, FAF retains exceptionally good fire resistance and high chemical durability, exhibits a rather closed-pore network, and requires temperatures below 80 °C for curing without the need for autoclaving. Experiments and micromechanical simulations prove that reasonable bulk densities lie in the range of 400–800 kg/m3.