Mössbauer, XRD, and Complex Thermal Analysis of the Hydration of Cement with Fly Ash. (11th November 2012)

• Record Type: Journal Article
• Authors: Lilkov, Vili; Petrov, Ognyan; Tzvetanova, Yana; Savov, Plamen; Kadiyski, Milen
• Other Names: Diniz Renata Academic Editor.
• Is Part Of: Journal of spectroscopy. Volume 2013(2013)
• Publication Date: 2012-11-11
• Subjects: Spectrum analysis -- Periodicals; 543.505
• DOI: 10.1155/2013/231843
• Languages: English
• ISSNs: 2314-4920

Abstract

Abstract : Hydration of cement with and without fly ash is studied with Mössbauer spectroscopy, XRD, and thermal analysis. Iron in cement is present as Fe 3+ -ions and occupies two octahedral positions, with close isomer shifts and quadrupole splittings. Iron in fly ash is present as Fe 2+ and Fe 3+, and the Mössbauer spectra display three doublets—two for Fe 3+ in octahedral coordination and one for Fe 2+ . A third doublet was registered in the hydrating plain cement pastes after the 5th day, due to Fe 3+ in tetrahedral coordination in the structure of the newly formed monosulphate aluminate. In cement pastes with fly ash, the doublet of tetrahedral iron is formed earlier because the quantity of ettringite and portlandite is low and more monosulphate crystallizes. No Fe(OH)3 phase forms during hydration of C4 AF. The fly ash displays pozzolanic properties, which lead to lowering of the portlandite quantity in the cement mixtures and increasing of the high temperature products.