Polymorphism of tricalcium silicate in Portland cement: A fast visual identification of structure and superstructure

Courtial, Mireille; Noirfontaine, Marie‐Noëlle de; Dunstetter, F.; Gasecki, G.; Signes-Frehel, M.

doi:10.1154/1.1523079

Cited by 60 publications

(35 citation statements)

References 9 publications

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“…1), with its two characteristic triplets (Fig. 2) in the two angular windows 2y Cu 5 311-33.51 and 2y Cu 5 511-52.31 respectively referred to as W3 and W5 in the study of Courtial et al 19 The positions of the C 3 S Bragg lines are well reproduced using the C 3 S triclinic unit cell parameters of the powder diffraction study of Regourd et al 20,21 The C 3 S Bragg lines are indexed on the basis of the structural model determined by Golovastikov et al 22,23 The indexation of the lines of the two triplets of the W3 and W5 windows is given by Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Noirfontaine

Tusseau‐Nenez

Signes-Frehel³

et al. 2009

Journal of the American Ceramic Society

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Alite is the major compound of anhydrous Portland cement: it is composed of tricalcium silicate Ca3SiO5 (C3S) modified in composition and crystal structure by ionic substitutions. Alite is also the main hydraulic phase of cement and the most important for subsequent strength development. Using raw meals (rich in Ca3P2O8) as alternative fuels in cement plants raises the question about the effect of phosphorus on C3S and its consequences on reactivity with water. This paper deals with a systematic study of C3S triclinic T1 polymorph doped with P2O5 in the range 0–0.9 wt%. All the samples were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), and electron‐microprobe analysis. The appearance of a phase rich in phosphorus is shown. It displays a structure derivative of the α′H–Ca2SiO4 polymorph, noted α′H–C2S(P). As phosphorus content increases, C3S is more and more decomposed into free lime and α′H–C2S(P). The α′H phase was detected from 0.1 wt% P2O5 and located at the interfaces of C3S grains. Two identification keys are proposed in order to highlight the α′H–C2S(P) phase: the XRD angular window at 2θCu=32.8°–33.2° and a smooth aspect on SEM micrographs.

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Section: Resultsmentioning

confidence: 99%

Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Noirfontaine

Tusseau‐Nenez

Signes-Frehel³

et al. 2009

Journal of the American Ceramic Society

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“…This method was validated and controlled on our data for triclinic, M 1 and M 3 compounds [21]. À À À À À À À À !…”

Section: Methodsmentioning

confidence: 99%

“…In a series of papers [18][19][20][21] we have proposed an extensive analysis of the polymorphism of tricalcium silicate, based on the superstructure relationships between the known structures, together with powder X-ray diffraction data analysis of synthetic alites M 1 and M 3 compared to M 1 and M 3 -based industrial clinkers. Only averaged models were discussed in [19].…”

Section: Introductionmentioning

confidence: 99%

Tricalcium silicate Ca₃SiO₅superstructure analysis: a route towards the structure of theM₁polymorph

Noirfontaine¹,

Courtial

Dunstetter

et al. 2012

Zeitschrift für Kristallographie

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M 1 alite / Polymorphism / Powder diffraction structure analysis / X-ray diffraction Abstract. In this paper, we present a structural model for the M 1 polymorph of tricalcium silicate Ca 3 SiO 5 from Powder X-Ray Diffraction (XRD) data, including weak intensity superstructure Bragg lines. As no single crystal is available, this structural model has been deduced using the structural relationships found between the previously known triclinic and monoclinic M 3 polymorphs.We find that the better starting set of atomic positions for Rietveld refinement is the triclinic set and not the monoclinic set. A key observation is that the monoclinic M 1 structure is closer to the low temperature triclinic T 3 structure (within the Golovastikov model) than to the higher temperature monoclinic M 3 structure.The unit cell and the set of atomic positions of the two best models, called 3hMiPc and 3hTiPn models, are provided. We prefer the 3hMiPc model for it better reproduces the weak characteristic Bragg lines of the superstructure.pure: T 1 ÀÀÀ! 620 C T 2 ÀÀÀ! 920 C T 3 ÀÀÀ! 980 C M 1 ÀÀÀ! 990 C M 2 ÀÀÀ! 1070 C R doped (mainly Zn or Mg): M 1 ÀÀÀ! 990 C M 2 ÀÀÀ! 1060 C M 3 ÀÀÀ! 1070 C R

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“…A small peak at 2θ = 59°is assigned to C 3 S [23,24]. The intensity is significantly low so that hydration degree can be concluded to near 100%.…”

Section: Xrdmentioning

confidence: 99%

Atomic and nano-scale characterization of a 50-year-old hydrated C3S paste

Geng

Taylor

Bae

et al. 2015

Cement and Concrete Research

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a b s t r a c tKeywords: TEM (B) NMR Microstructure Ca 3 SiO 5 (D) STXM This paper investigates the atomic and nano-scale structures of a 50-year-old hydrated alite paste. Imaged by TEM, the outer product C-S-H fibers are composed of particles that are 1.5-2 nm thick and several tens of nanometers long. 29 Si NMR shows 47.9% Q 1 and 52.1% Q 2 , with a mean SiO 4 tetrahedron chain length (MCL) of 4.18, indicating a limited degree of polymerization after 50 years' hydration. A Scanning Transmission X-ray Microscopy (STXM) study was conducted on this late-age paste and a 1.5 year old hydrated C 3 S solution. Near Edge X-ray Absorption Fine Structure (NEXAFS) at Ca L 3,2 -edge indicates that Ca 2+ in C-S-H is in an irregular symmetric coordination, which agrees more with the atomic structure of tobermorite than that of jennite. At Si K-edge, multiscattering phenomenon is sensitive to the degree of polymerization, which has the potential to unveil the structure of the SiO 4 4− tetrahedron chain.

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Polymorphism of tricalcium silicate in Portland cement: A fast visual identification of structure and superstructure

Cited by 60 publications

References 9 publications

Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Tricalcium silicate Ca₃SiO₅superstructure analysis: a route towards the structure of theM₁polymorph

Atomic and nano-scale characterization of a 50-year-old hydrated C3S paste

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Polymorphism of tricalcium silicate in Portland cement: A fast visual identification of structure and superstructure

Cited by 60 publications

References 9 publications

Effect of Phosphorus Impurity on Tricalcium Silicate T1: From Synthesis to Structural Characterization

Effect of Phosphorus Impurity on Tricalcium Silicate T1: From Synthesis to Structural Characterization

Tricalcium silicate Ca3SiO5superstructure analysis: a route towards the structure of theM1polymorph

Atomic and nano-scale characterization of a 50-year-old hydrated C3S paste

Contact Info

Product

Resources

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Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Effect of Phosphorus Impurity on Tricalcium Silicate T₁: From Synthesis to Structural Characterization

Tricalcium silicate Ca₃SiO₅superstructure analysis: a route towards the structure of theM₁polymorph