Overview of different types of fly ash and their use as a building and construction material

Abstract

Fly ash is produced, in massive amount, as a waste material of burning fossil fuel (coal combustion) for the thermal generation of electricity. Currently about 900 million tonnes of fly ash produced, worldwide, annually and about 30-40% of this residue is being utilized for various purposes including in cement and concrete production. Disposing the remaining percentage is costly as it should be done carefully to avoid any environmental pollution, mainly groundwater contamination. There are different types of fly ash, including Class F and Class C, generated by burning black coal and brown coal respectively. Class F and Class C are being utilized in making building materials such as concrete, lightweight aggregate, bricks etc. Also fly ash is used as a material for road construction and earth filled dam construction. This paper outlines an overview of using fly ash as a raw material in producing various building materials and methods of how fly ash is being incorporated with other materials. The major benefits and limitations of using fly ash as a building and construction materials are discussed.