Transition from brittle to ductile behavior of fly ash using PVA fibers

In this study, short polyvinyl alcohol (PVA) fibers are employed to improve the mechanical properties of brittle fly ash samples, which are solidified by a small amount of sodium hydroxide (NaOH) and by a hydrothermal hot-pressing process. The mechanical properties of the PVA fiber reinforced fly ash composites are evaluated by splitting tensile test. Several key factors such as fiber content, processing temperature, and processing duration are investigated. The effect of different types of fly ash (Class C vs. Class F) is also studied. The experimental results demonstrate that the addition of short PVA fibers can significantly improve the ductility of the fly ash composites. The optimum fiber volume content is estimated to be 1.0% with Class C fly ash.