A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum
This paper shows the microstructural differences and phase characterization of pure phases and hydrated products of the cubic and orthorhombic (Na-doped) polymorphs of tricalcium aluminate (C3A), which are commonly found in traditional Portland cements. Pure, anhydrous samples were characterized usi...
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doaj-036fc28ff2474e509cf248ff9941b1992020-11-24T23:37:58ZengMDPI AGMaterials1996-19442016-08-019974510.3390/ma9090745ma9090745A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of GypsumVanessa Rheinheimer0Sejung Rosie Chae1Erich D. Rodríguez2Guoqing Geng3Ana Paula Kirchheim4Paulo J. M. Monteiro5Berkeley Education Alliance for Research in Singapore–BEARS, Singapore 138602, SingaporeDepartment of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USADepartment of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre 90035-190, RS, BrazilDepartment of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USADepartment of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre 90035-190, RS, BrazilDepartment of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USAThis paper shows the microstructural differences and phase characterization of pure phases and hydrated products of the cubic and orthorhombic (Na-doped) polymorphs of tricalcium aluminate (C3A), which are commonly found in traditional Portland cements. Pure, anhydrous samples were characterized using scanning transmission X-ray microscopy (STXM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and demonstrated differences in the chemical and mineralogical composition as well as the morphology on a micro/nano-scale. C3A/gypsum blends with mass ratios of 0.2 and 1.9 were hydrated using a water/C3A ratio of 1.2, and the products obtained after three days were assessed using STXM. The hydration process and subsequent formation of calcium sulfate in the C3A/gypsum systems were identified through the changes in the LIII edge fine structure for Calcium. The results also show greater Ca LII binding energies between hydrated samples with different gypsum contents. Conversely, the hydrated samples from the cubic and orthorhombic C3A at the same amount of gypsum exhibited strong morphological differences but similar chemical environments.http://www.mdpi.com/1996-1944/9/9/745tricalcium aluminategypsumscanning transmission X-ray microscopyhydration |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Vanessa Rheinheimer Sejung Rosie Chae Erich D. Rodríguez Guoqing Geng Ana Paula Kirchheim Paulo J. M. Monteiro |
spellingShingle |
Vanessa Rheinheimer Sejung Rosie Chae Erich D. Rodríguez Guoqing Geng Ana Paula Kirchheim Paulo J. M. Monteiro A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum Materials tricalcium aluminate gypsum scanning transmission X-ray microscopy hydration |
author_facet |
Vanessa Rheinheimer Sejung Rosie Chae Erich D. Rodríguez Guoqing Geng Ana Paula Kirchheim Paulo J. M. Monteiro |
author_sort |
Vanessa Rheinheimer |
title |
A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum |
title_short |
A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum |
title_full |
A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum |
title_fullStr |
A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum |
title_full_unstemmed |
A Scanning Transmission X-ray Microscopy Study of Cubic and Orthorhombic C3A and Their Hydration Products in the Presence of Gypsum |
title_sort |
scanning transmission x-ray microscopy study of cubic and orthorhombic c3a and their hydration products in the presence of gypsum |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2016-08-01 |
description |
This paper shows the microstructural differences and phase characterization of pure phases and hydrated products of the cubic and orthorhombic (Na-doped) polymorphs of tricalcium aluminate (C3A), which are commonly found in traditional Portland cements. Pure, anhydrous samples were characterized using scanning transmission X-ray microscopy (STXM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and demonstrated differences in the chemical and mineralogical composition as well as the morphology on a micro/nano-scale. C3A/gypsum blends with mass ratios of 0.2 and 1.9 were hydrated using a water/C3A ratio of 1.2, and the products obtained after three days were assessed using STXM. The hydration process and subsequent formation of calcium sulfate in the C3A/gypsum systems were identified through the changes in the LIII edge fine structure for Calcium. The results also show greater Ca LII binding energies between hydrated samples with different gypsum contents. Conversely, the hydrated samples from the cubic and orthorhombic C3A at the same amount of gypsum exhibited strong morphological differences but similar chemical environments. |
topic |
tricalcium aluminate gypsum scanning transmission X-ray microscopy hydration |
url |
http://www.mdpi.com/1996-1944/9/9/745 |
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