A comprehensive study on the production of autoclaved aerated concrete: Effects of silica-lime-cement composition and autoclaving conditions

This study describes the effects of raw mix composition, amount of foaming agent, water-solids ratio, steam pressure, and curing time on the characteristics of autoclaved aerated concrete (AAC). The bulk density, compressive strength, and microstructures of AAC specimens were examined, and X-ray diffraction, mercury intrusion porosimetry, and thermal analyses were employed. The bulk density of AAC was affected by the amount of aluminum powder added and water-solids ratio, and especially the latter. An increase in the amount of cement was not beneficial to the development of compressive strength. In contrast, autoclave curing greatly enhanced the compressive strength, and the AAC specimen autoclaved at 12 atm for 16 h had the highest compressive strength of 13.3 MPa. Increasing steam pressure can notably reduce the curing time, based on similar requirements of compressive strength. In contrast, prolonging curing time was helpful to the development of compressive strength under low steam pressure conditions.