Recycling by-products from coal-fired power stations into different construction materials

Abstract

The present investigation aims to analyse alternative uses of bottom ash and fly ash as part of construction materials for different applications: bottom ashbased ceramic bricks, pozzolanic material in the cement production, waste stabilisation/solidification of an electric arc furnace dust using ash-based geopolymers, and ashbased geopolymers used as hydraulic road binders. Different replacements of natural materials by different fly and/or bottom ashes have been studied in all the cases. This study has analysed various parameters influencing the manufacturing process, with the aim of reducing the energy consumption of these processes, as they have been, for example, the firing temperature of bricks and grind size of bottom ashes in cements. All materials are manufactured in a simple and economical way, in order not to increase the cost of the products, and the final products have been evaluated according to different European standards used in these applications, in order to assess their possible, actual technical feasibility. The results obtained in this study show that even higher ratios of replacement ([40 %) of ashes have properties similar to those commonly used.