The incorporation of minor and trace elements into calcium silicate hydrate (CSH) gel in hardened cement pastes

Richardson, Ian; Groves, G. W.

doi:10.1016/0008-8846(93)90143-w

Cited by 235 publications

(98 citation statements)

References 7 publications

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“…The lineshapes of the spectra for the samples equilibrated at ≤ 50°C and the same bulk Al/Si ratio are similar, which indicates that the C-(A-)S-H products formed in these samples have similar degrees of polymerisation, as shown in Figure 7, calculated using eq. (2) for noncross-linked C-(A-)S-H (subscript NC) [57]. Al/Si ratios for non-cross-linked C-(A-)S-H are calculated by eq.…”

Section: Si Magic Angle Spinning Nuclear Magnetic Resonancementioning

confidence: 99%

“…C-(A-)S-H structural parameters calculated from deconvolution analysis of the 29 Si MAS NMR spectra, determined using the 'Substituted General Model' [57] for the non-crosslinked phases and the 'Cross-linked Substituted Tobermorite Model' [17] for the cross-linked phases. The sizes of the symbols represent the expected error bounds of the deconvolution results, except for the Al/Si* = 0.1, 80°C sample, where the uncertainty of the MCL calculation is represented by error bars.…”

Section: Si Magic Angle Spinning Nuclear Magnetic Resonancementioning

confidence: 99%

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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

311

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: Si Magic Angle Spinning Nuclear Magnetic Resonancementioning

confidence: 99%

Section: Si Magic Angle Spinning Nuclear Magnetic Resonancementioning

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

311

130

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“…Slags, whose slow hydration needs activation, produce analogous hydration products to cement, 36 mainly a C-S-H, albeit with a lower Ca/Si ratio and increased Al/Si 7,8 . Furthermore, a change in 37 aluminate, carbonate and sulphate content can further upset the hydrate assemblage, especially the 38 ettringite and AFm distribution 9 , while, a hydrotalcite-like phase may also form 1 .…”

mentioning

confidence: 99%

The role of the alumina content of slag, plus the presence of additional sulfate on the hydration and microstructure of Portland cement-slag blends

Whittaker

Zając

Haha

et al. 2014

Cement and Concrete Research

147

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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. Abstract: The effects on composite cements of the aluminium content of slag plus that of additional sulphate, has been investigated. Samples containing cement or composites with 40% replacement by one of 2 different slags, differing in aluminium contents, were prepared. A further blended sample was prepared with additional anhydrite replacing 3%w/w of binder. Slag blended mortars showed comparable strengths to the neat cement system at later ages. Adding slag changed the hydration kinetics of the clinker phases. The addition of sulphate had no effect on slag reactivity but increased that of alite. Slags richer in aluminium resulted in greater incorporation of aluminium into C-S-H and encouraged the presence of hemicarbonate over monocarbonate. The Ca/Si ratios of the C-S-H formed were comparable between the two blends, being marginally lower than that of the neat system. The addition of anhydrite resulted in the adsorption of sulphate onto the C-S-H, plus stabilisation of ettringite. Corresponding Author 8 9 The Role of the Alumina Content of Slag, plus the Presence of AdditionalAbstract 10 The effects on composite cements of the aluminium content of slag plus that of additional sulphate, 11 has been investigated. Samples containing cement or composites with 40% replacement by one of 2 12 different slags, differing in aluminium contents, were prepared. A further blended sample was 13 prepared with additional anhydrite replacing 3%w/w of binder. Slag blended mortars showed 14 comparable strengths to the neat cement system at later ages. Adding slag changed the hydration 15 kinetics of the clinker phases. The addition of sulphate had no effect on slag reactivity but increased 16 that of alite. Slags richer in aluminium resulted in greater incorporation of aluminium into C-S-H and 17 encouraged the presence of hemicarbonate over monocarbonate.

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“…The addition of a sufficient amount of SCMs leads to formation of calcium-silicate-hydrate (C-S-H) gel with a low Ca/Si ratio, resulting in a low alkalinity of the pore solution (Hong and Glasser 1999). When Al-including SCMs are added in the mix, Al substitutes the bridging site of Si in C-S-H gel (Richardson and Groves 2003). The influence of aluminium on alkalinity of pore solution remains controversial.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Alkalinity of Pore Solution Based on the Phase Composition of Cement Hydrates with Supplementary Cementitious Materials and its Relation to Suppressing ASR Expansion

Kawabata

Yamada

2015

ACT

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A model to evaluate quantitatively the alkalinity of pore solution based on phase composition of cement hydrates with SCMs was proposed and was compared with suppressing effect of ASR expansion. The model is devised from the perspective of alkali sorption by C-S-H gel, and the parameters for calculation can be evaluated thanks to phase composition analysis such as XRD/Rietveld analysis and selective dissolution. The experimental results have shown that ASR expansion is strongly correlated to the alkalinity of the pore solution, which can be calculated with the proposed model. Based on the results, the ASR suppressing effects of SCMs are converted to the reduction in total alkali content as available alkali content. Finally, the required replacement level of SCM with the proposed model was compared to the CSA A23.2-27A standard based on numerous experiments and field experiences in Canada. The calculated result was well consistent with the minimum replacement level of SCMs specified in CSA A23.2-27A. A subsequent interpretation of this study supports that the dominant mechanism of SCMs for ASR suppression is a reduction of alkalinity of pore solution.

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The incorporation of minor and trace elements into calcium silicate hydrate (CSH) gel in hardened cement pastes

Cited by 235 publications

References 7 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

The role of the alumina content of slag, plus the presence of additional sulfate on the hydration and microstructure of Portland cement-slag blends

Evaluation of Alkalinity of Pore Solution Based on the Phase Composition of Cement Hydrates with Supplementary Cementitious Materials and its Relation to Suppressing ASR Expansion

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