Alkali-Activated Binders From Waste Incinerator Bottom Ashes and Metakaolin Reinforced by Recycled Carbon Fiber Composites

In view of creating low-impact materials for the building industry, the fostering of alkali-activated binder gains high importance. Metakaolin can successfully be activated with alkalis at room temperature, but the contemporary use of wastes to create mixed binders can further increase the environmental benefits. Bottom ashes obtained from the incineration of municipal solid wastes have been tentatively mixed in different amounts to develop matrix with acceptable mechanical properties, which still can be cured at room temperature. Moreover, scraps obtained from the production of epoxy/carbon fiber composites are employed as a reinforcing phase. No chemical or physical treatments have been used to modify the epoxy/carbon fiber wastes, apart from size reduction, thus minimizing the overall economic and energy impact of the process. The workability, physical and mechanical properties, microstructure, and porosity of the obtained materials are investigated. Up to a 50 weight percent of bottom ashes from municipal solid waste incineration can be mixed with metakaolin. Fibers still embedded in the epoxy matrix disclose a fair interaction with the matrix, thus managing to increase flexural strength, toughness, and dimensional stability without decreasing the compressive strength.