Compositional Evolution of Calcium Silicate Hydrate (<scp><scp>C–S–H</scp></scp>) Structures by Total<scp>X</scp>‐Ray Scattering

Soyer-Uzun, Sezen; Chae, Sejung Rosie; Benmore, C. J.; Wenk, Hans‐Rudolf; Monteiro, Paulo J.M.

doi:10.1111/j.1551-2916.2011.04989.x

Cited by 92 publications

(79 citation statements)

References 39 publications

(97 reference statements)

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“…The intensities of G ( r ) in all PDF were rescaled based on the peak intensity of Ca 1 –Si 1 in the PDF of C 3 S paste. In PDFs of cementitious phases, the correlations at ~1.6 Å are related to the average Si 1 –O 1 bond in tetrahedrally coordinated SiO 2 as previously found in synthetic C–S–H and tobermorite . Soyer‐Uzen et al .…”

Section: Resultssupporting

confidence: 57%

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

et al. 2017

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Despite enormous interest in calcium silicate hydrate (C-S-H), its detailed atomic structure and intrinsic deformation under an external load are lacking. This study demonstrates the nanostructural deformation process of C-S-H in tricalcium silicate (C 3 S) paste as a function of applied stress by interpreting atomic pair distribution function (PDF) based on in situ X-ray scattering. Three different strains in C 3 S paste under compression were compared using a strain gauge, Bragg peak shift, and the real space PDF. PDF refinement revealed that the C-S-H phase mostly contributed to PDF from 0 to 20 A whereas crystalline phases dominated that beyond 20 A. The short-range atomic strains exhibited two regions for C-S-H: I) plastic deformation (0-10 MPa) and II) linear elastic deformation (>10 MPa), whereas the long-range deformation beyond 20 A was similar to that of Ca(OH) 2 . Below 10 MPa, the short-range strain was caused by the densification of C-S-H induced by the removal of interlayer or gel-pore water. The strain is likely to be recovered when the removed water returns to C-S-H. K E Y W O R D Scalcium silicate hydrate, deformation, portland cement, X-ray methods

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Section: Resultssupporting

confidence: 57%

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

et al. 2017

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“…In a study to quantify the order and disorder of the molecular structure, Bauchy et al [149] showed that while C-S-H retains some signatures of a tobermoritelike layered structure, hydrated species are completely amorphous. Their modeling captured the main features of pair distribution function results [150] of synthetic C-S-H.…”

Section: Atomistic Modelingmentioning

confidence: 99%

Advances in understanding hydration of Portland cement

Scrivener

Juilland²,

Monteiro

2015

Cement and Concrete Research

938

340

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“…In order to shed light and open questions in the chemistry and local atomic structure of C-S-H gels, neutron and synchrotron total scattering data analyzed by PDF methodology have been used, and these studies have been reviewed [25,26]. Here, we distinguish the PDF studies on synthetic C-S-H gels [13,[27][28][29] from those carried out for C-S-H gels formed from the hydration of alite [29][30][31], as the local atomic arrangements could be quite different. These investigations have revealed that the C-S-H gel from alite hydration presents a nanocrystalline nature with atomic ordering up to approximately 40 Å [29,31].…”

Section: X-ray Pair Distribution Function Analysismentioning

confidence: 99%

Synchrotron Radiation Pair Distribution Function Analysis of Gels in Cements

et al. 2017

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Abstract:The analysis of atomic ordering in a nanocrystalline phase with small particle sizes, below ≈5 nm, is intrinsically complicated because of the lack of long-range order. Furthermore, the presence of additional crystalline phase(s) may exacerbate the problem, as is the case in cement pastes. Here, we use the synchrotron pair distribution function (PDF) chiefly to characterize the local atomic order of the nanocrystalline phases, gels, in cement pastes. We have used a multi r-range analysis approach, where the~4-7 nm r-range allows determining the crystalline phase contents; the~1-2.5 nm r-range is used to characterize the atomic ordering in the nanocrystalline component; and the~0.2-1.0 nm r-range gives insights about additional amorphous components. Specifically, we have prepared four alite pastes with variable water contents, and the analyses showed that a defective tobermorite, Ca 11 Si 9 O 28 (OH) 2 ·8.5H 2 O, gave the best fit. Furthermore, the PDF analyses suggest that the calcium silicate hydrate gel is composed of this tobermorite and amorphous calcium hydroxide. Finally, this approach has been used to study alternative cements. The hydration of monocalcium aluminate and ye'elimite pastes yield aluminum hydroxide gels. PDF analyses show that these gels are constituted of nanocrystalline gibbsite, and the particle size can be as small as 2.5 nm.

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Compositional Evolution of Calcium Silicate Hydrate (C–S–H) Structures by TotalX‐Ray Scattering

Cited by 92 publications

References 39 publications

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

Advances in understanding hydration of Portland cement

Synchrotron Radiation Pair Distribution Function Analysis of Gels in Cements

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