Fly Ash From Fluidized Bed Coal Combustion as Complex Cement Addition

Fluidized bed coal combustion produces a new kind of fly ash by-product. Fluidized bed fly ashes have different chemical composition and physical properties than conventional fly ashes. They can be used as complex additions to cement where they play simultaneously the role of sulphate setting time controlling agent and high active pozzolanic admixture as well. This gives the possibility to reduce the consumption of portland cement clinker and gypsum. Thus, it may also contribute to the reduction of carbon dioxide emissions. In the paper the results of the laboratory investigations of fluidized bed fly ashes as cement additive and the effects of their industrial implementation will be presented.