Fly ash

Abstract

Fly ash is an industrial by-product deriving from electricity generating plants. It is the by-product of burning coal or lignite. Fly ash is one of the first artificial admixtures used for the production of concrete since the first decades of the 20th century. Its chemical and mineralogical composition mainly depends on the relevant properties of the raw material used as well as on the type of furnace and the way it is collected. Fly ash may have beneficial effects on both the fresh and hardened properties of concrete mixtures. This chapter provides an extensive report on the use of fly ash in concrete. Reference is made to the regulatory framework governing the application of fly ash, mainly in Europe and America, to factors affecting the quality of the product and to the effects of different fly ashes on fresh and hardened characteristics of concrete.