Influence of Fluidized Ashes on Properties of Autoclaved Aerated Concrete

Coal fly ash, a by-product of coal combustion in thermal power plants, is one of the most complex and abundant anthropogenic materials. For several years, siliceous fly ash has been predominantly used as a substitute for material in the construction industry, either as a raw material or as an additive in the cement industry all over the world. Fly ash produced in coal-fired plants based on fluidized bed combustion technology accompanied by in-furnace desulfurization has significantly different properties compared to siliceous ashes. In this study, a brief characterization of fly ash from fluidized bed boilers is presented and possible alterations in fly ash use in autoclaved concrete production are discussed. Autoclaved aerated concrete production involving fluidized ashes proved to be more cost-effective and environmentally friendly. The content of lime and sulfates was found to be reduced by 10% to 20% and 60% to 100%, respectively, which limited the exploitation and consumption of the natural raw materials.