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Characterisation of reactive magnesia and sodium carbonate-activated fly ash/slag paste blends

Abdalqader, AF and Jin, F and Al-Tabbaa, A (2015) Characterisation of reactive magnesia and sodium carbonate-activated fly ash/slag paste blends. Construction and Building Materials, 93. pp. 506-513. ISSN 0950-0618

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Abstract

© 2015 Elsevier Ltd. All rights reserved. A system of alkali-activated fly ash (FA)/slag (AAFS) mixtures as a clinkerless cement was investigated with different dosages of Na < inf > 2 < /inf > CO < inf > 3 < /inf > , as a sustainable activator. The effect of incorporating various proportions of reactive magnesia (MgO) was also examined. Mechanical, mineralogical, and microstructural characterisation of the cement pastes was carried out using the unconfined compressive strength, X-ray diffraction, thermogravimetric analysis, infrared spectroscopy and scanning electron microscopy. It was found that the strength of Na < inf > 2 < /inf > CO < inf > 3 < /inf > activated FA/slag mixtures generally increased with time and the Na < inf > 2 < /inf > CO < inf > 3 < /inf > dosage. The hydration products were mainly C-(N)-A-S-H gel of low-crystallinity, which is rich in Al and may have included Na in its structure, and hydrotalcite-like phases. Adding reactive MgO in the mixes showed an accelerating effect on the hydration rate as suggested by the isothermal calorimetry data. Additionally, findings revealed variations on the strength of the pastes and the chemical compositions of the hydration products by introducing reactive MgO into the mixtures.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 18:59
Last Modified: 16 Nov 2017 02:10
DOI: