Application of the Rietveld Refinement Procedure in Assaying Powdered Mixtures

O’Connor, B. H.; Raven, Mark

doi:10.1017/s0885715600013026

Cited by 268 publications

(145 citation statements)

References 10 publications

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“…Powder XRD patterns were recorded on a PANalytical X'Pert Pro MDF diffractometer equipped with a Ge(111) Johansson monochromator for Cu K radiation, and an X'Celerator detector, and a step size of 0.017° 2 . An external CaF 2 standard was used for Rietveld analysis, enabling quantification of the amount of C-(A-)S-H in each sample [25]. Average basal (d (002) ) spacings of the C-(A-)S-H products were determined by visual inspection.…”

Section: C-(a-)s-mentioning

confidence: 99%

Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

Myers

L’Hôpital

Provis

et al. 2015

Cement and Concrete Research

320

130

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. KeywordsTemperature, Calcium-Silicate-Hydrate (C-S-H), Thermodynamic Calculations, Hydration Products, Blended Cement. AbstractThere exists limited information regarding the effect of temperature on the structure and solubility of calcium aluminosilicate hydrate (C-A-S-H). Here, calcium (alumino)silicate hydrate (C-(A-)S-H) is synthesised at Ca/Si = 1, Al/Si ≤ 0.15 and equilibrated at 7-80°C. These systems increase in phase-purity, long-range order, and degree of polymerisation of C-(A-)S-H chains at higher temperatures; the most highly polymerised, crystalline and crosslinked C-(A-)S-H product is formed at Al/Si = 0.1 and 80°C. Solubility products for C-(A-)S-H were calculated via determination of the solid-phase compositions and measurements of the concentrations of dissolved species in contact with the solid products, and show that the solubilities of C-(A-)S-H change slightly, within the experimental uncertainty, as a function of Al/Si ratio and temperature between 7°C and 80°C. These results are important in the development of thermodynamic models for C-(A-)S-H to enable accurate thermodynamic modelling of cement-based materials. IntroductionTemperatures experienced by cement and concrete based construction materials in service can vary greatly, due to heat evolution from cement hydration, variable ambient environmental conditions, steam curing, and other factors. understanding of the nature of C-S-H and other constituent phases in these systems at equilibrium [6][7][8][9] has meant that hydrated neat PC materials can be accurately described by thermodynamic modelling at temperatures from 5°C to above 80°C [10]. Extending this analysis to the CaO-Al 2 O 3 -SiO 2 -H 2 O system represents a major step toward applying this technique to hydrated PC blends with high replacement levels of supplementary cementitious materials, which are not fully described by existing thermodynamic models [11]. This will enable a much deeper understanding of the chemistry and phase composition, and hence durability, of these materials in service.The chemistry and structure of calcium (alumino)silicate hydrate (C-(A-)S-H) products at ambient conditions have been the subject of sustained research for more than half a...

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Section: C-(a-)s-mentioning

confidence: 99%

Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

Myers

L’Hôpital

Provis

et al. 2015

Cement and Concrete Research

320

130

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“…Hereafter, this derived value will be called Amorphous and Crystalline not-quantified, ACn [38]. The absolute weight fractions for all crystalline phases are derived using the G-factor approach from their refined phase fractions, and ACn contents are obtained from the difference of the total crystalline phases to 100, knowing the mass attenuation coefficients of the samples [39,40].…”

Section: Lxrpd Data Analysismentioning

confidence: 99%

Hydration studies of calcium sulfoaluminate cements blended with fly ash

García-Maté

Torre

León‐Reina

et al. 2013

Cement and Concrete Research

171

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The main objective of this work is to study the hydration and properties of calcium sulfoaluminate cement pastes blended with fly ash (FA) and the corresponding mortars at different hydration ages. Laboratory X-ray powder diffraction, rheological studies, thermal analysis, porosimetry and compressive strength measurements were performed. The analysis of the diffraction data by Rietveld method allowed quantifying crystalline phases and overall amorphous contents. The studied parameters were: i) FA content, 0, 15 and 30 wt.%; and ii) water addition, water-to-CSA mass ratio (w/CSA = 0.50 and 0.65), and water-to-binder mass ratio (w/b = 0.50). Finally, compressive strengths after 6 months of 0 and 15 wt.% FA [w/CSA = 0.50] mortars were similar: 73 ± 2 and 72 ± 3 MPa, respectively. This is justified by the filler effect of the FA as no strong evidences of reactivity of FA with CSA were observed. These results support the partial substitution of CSA cements with FA with the economic and environmental benefits.

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“…2, 3 and 4 with respect to the regression line may be due to the presence of an amorphous component in the added spikes. In fact, it is well known that ground quartz and corundum may be coated with amorphous layers (Nagelschmidt et al, 1952;O'Connor & Raven, 1988).…”

Section: Figurementioning

confidence: 99%

Accuracy of XRPD QPA using the combined Rietveld–RIR method

2000

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QPA (quantitative phase analysis) of polycrystalline materials using XRPD (Xray powder diffraction) can be performed using the combined Rietveld and reference intensity ratio (RIR) methods, providing an estimate of both the crystalline and the amorphous phase in a mixture. Although the accuracy of estimates of the phase composition of simple ternary or quaternary mixtures is generally very good, uncertainties remain and bias the accuracy of phase determinations in complex systems such as pyroclastic rocks, which may contain two or more zeolite species, a number of other phases (generally up to four or ®ve), and glass. The contribution of the incoherent scattering, biasing accuracy, in the glass determination has been discussed in an earlier work on the modal analysis of pyroclastic rocks [Gualtieri (1996). Powder Diffr. 11, 97±106]. In this work, the assumption of the crystal structure, the in¯uence of the spike addition, background and atomic (thermal) displacement parameters are discussed. It is shown that the structure-model assumption no longer holds for systems containing complex phases such as zeolites, as the accuracy is degraded and, as far as the in¯uence of the added spike is concerned, there is an underestimation of the glass content with increasing amounts of added spike.

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Application of the Rietveld Refinement Procedure in Assaying Powdered Mixtures

Cited by 268 publications

References 10 publications

Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

Hydration studies of calcium sulfoaluminate cements blended with fly ash

Accuracy of XRPD QPA using the combined Rietveld–RIR method

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