Effect of the Addition of Unreacted Ilmenite (UOW) on the Hydration of White Portland Cement - Hydrated Lime Pastes

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This paper evaluates the effect of the incorporation of unreacted ilmenite (UOW), waste from the production of titanium dioxide, on the hydration of white Portland cement – hydrated lime pastes. For this, after the physical and mineralogical characterization of the raw materials, pastes with additions of 5%, 10% and 15% of UOW, in relation to cement weight, besides a reference paste (without UOW), were molded. Tests of setting time determination by Vicat needle and semi-adiabatic calorimetry tests were carried out, as well as thermogravitry analysis of pastes at 7 days of curing. The addition of UOW, due to the presence of anhydrite (calcium sulphate) in its composition, is responsible for delaying the hydration of the white Portland cement – hydrated lime pastes, increasing the setting time and reducing the heat release. Despite the influence in the first hours, the waste did not influence significantly the contents of combined water and portlandite formed in the pastes at 7 days.

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289-293

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May 2019

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© 2019 Trans Tech Publications Ltd. All Rights Reserved

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