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Title: Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H

Abstract

Low-Q region Rietveld analyses were performed on C-S-H synchrotron XRD patterns, using the software MAUD. Two different crystal structures of tobermorite 11 A were used as a starting model: monoclinic ordered Merlino tobermorite, and orthorhombic disordered Hamid tobermorite. Structural modifications were required to adapt the structures to the chemical composition and the different interlayer spacing of the C-S-H samples. Refinement of atomic positions was done by using special constraints called fragments that maintain interatomic distances and orientations within atomic polyhedra. Anisotropic crystallite size refinement showed that C-S-H has a nanocrystalline disordered structure with a preferred direction of elongation of the nanocrystallites in the plane of the Ca interlayer. The quality of the fit showed that the monoclinic structure gives a more adequate representation of C-S-H, whereas the disordered orthorhombic structure can be considered a more realistic model if the lack of long-range order of the silica chain along the c-direction is assumed.

Authors:
 [1];  [2];  [1]
  1. Department of Earth and Planetary Sciences, University of California, Berkeley, CA 94720 (United States)
  2. Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)
Publication Date:
OSTI Identifier:
22149356
Resource Type:
Journal Article
Journal Name:
Cement and Concrete Research
Additional Journal Information:
Journal Volume: 42; Journal Issue: 11; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0008-8846
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; CALCIUM SILICATES; CHEMICAL COMPOSITION; COMPUTER CODES; CRYSTALS; ELONGATION; HYDRATES; INTERATOMIC DISTANCES; LIMITING VALUES; MONOCLINIC LATTICES; NANOSTRUCTURES; ORIENTATION; ORTHORHOMBIC LATTICES; SYNCHROTRONS; X-RAY DIFFRACTION

Citation Formats

Battocchio, Francesco, Monteiro, Paulo J.M., E-mail: monteiro@berkeley.edu, and Wenk, Hans-Rudolf. Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H. United States: N. p., 2012. Web. doi:10.1016/J.CEMCONRES.2012.07.005.
Battocchio, Francesco, Monteiro, Paulo J.M., E-mail: monteiro@berkeley.edu, & Wenk, Hans-Rudolf. Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H. United States. doi:10.1016/J.CEMCONRES.2012.07.005.
Battocchio, Francesco, Monteiro, Paulo J.M., E-mail: monteiro@berkeley.edu, and Wenk, Hans-Rudolf. Thu . "Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H". United States. doi:10.1016/J.CEMCONRES.2012.07.005.
@article{osti_22149356,
title = {Rietveld refinement of the structures of 1.0 C-S-H and 1.5 C-S-H},
author = {Battocchio, Francesco and Monteiro, Paulo J.M., E-mail: monteiro@berkeley.edu and Wenk, Hans-Rudolf},
abstractNote = {Low-Q region Rietveld analyses were performed on C-S-H synchrotron XRD patterns, using the software MAUD. Two different crystal structures of tobermorite 11 A were used as a starting model: monoclinic ordered Merlino tobermorite, and orthorhombic disordered Hamid tobermorite. Structural modifications were required to adapt the structures to the chemical composition and the different interlayer spacing of the C-S-H samples. Refinement of atomic positions was done by using special constraints called fragments that maintain interatomic distances and orientations within atomic polyhedra. Anisotropic crystallite size refinement showed that C-S-H has a nanocrystalline disordered structure with a preferred direction of elongation of the nanocrystallites in the plane of the Ca interlayer. The quality of the fit showed that the monoclinic structure gives a more adequate representation of C-S-H, whereas the disordered orthorhombic structure can be considered a more realistic model if the lack of long-range order of the silica chain along the c-direction is assumed.},
doi = {10.1016/J.CEMCONRES.2012.07.005},
journal = {Cement and Concrete Research},
issn = {0008-8846},
number = 11,
volume = 42,
place = {United States},
year = {2012},
month = {11}
}