Mineralogical and Chemical Properties of Mortar Incorporating Coal Ash Produced by Fluidized Bed Combustion

A pressurized fluidized bed combustion thermal power plant (PFBC) is a coal-fired thermal power plant specially developed for the enhancement of generating efficiency and the reduction of environmental loads. The physiochemical properties of coal ash produced from this type of power plant (PFBC ash) are different from those ordinary fly ash, because coal is mixed with crushed limestone and burned at a lower temperature than that in the conventional power generation system. This study explores the feasibility of utilizing PFBC ash as a concrete admixture. It has been found that the coal ash from a secondary cyclone dust collector enhances the strength of concrete although it cannot improve the fluidity. A variety of chemical analyses were carried out to explain the reason why the coal ash so produced has such effects. The fly ash obtained from a secondary cyclone dust collector was found to enhance mortar strength due to the hydration of sulfur containing minerals such as gypsum and the pozzolanic reaction of fine-grain silica. Thus, the feasibility of using it as concrete admixture has been verified.