5 - The properties and durability of clay fly ash-based fired masonry bricks

Abstract

In the thermal power stations, huge amounts of coal combustion fly ashes are discarded. The fly ashes have very different chemical, mineralogical, and physical compositions, depending on factors such as source and type of coal and the combustion process. They can contain appreciable amounts of highly toxic trace elements. Because of this, the fly ashes are recognized as an environmental pollutant. A significant amount of coal combustion fly ashes produced worldwide is still disposed of in landfills and ash lagoons, costing money and causing environmental impact. Thus, disposal of fly ashes in an environmentally safe manner is a major challenge for thermal power stations using coal as a combustible. The reuse of fly ash as a partial replacement for common clay into fired clay masonry bricks appears to be a viable economic, safe, and sustainable option. This chapter focuses on the reuse of coal combustion fly ash as an alternative raw material to produce clay-based fired masonry bricks. Emphasis is given to the fly ash characteristics and its influence on the physical and mechanical properties. It also covers the durability of the clay-based fired masonry bricks.