The nature of C-S-H in hardened cements

Richardson, Ian

doi:10.1016/s0008-8846(99)00168-4

Cited by 870 publications

(435 citation statements)

References 57 publications

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“…The Al/Si ratio also remained 259 constant, with a value close to 0.1. These values are similar to those in the literature; where the 260 effect of slag on C-S-H composition and morphology are well reported and a C-S-H with a lower Ca/Si 261 and higher Al/Si atomic ratio is ultimately formed 32,52,53,54 . 262…”

supporting

confidence: 88%

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

150

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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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supporting

confidence: 88%

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

150

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“…In particular, it is well known that this favours the formation of inner C-S-H. Likewise, an increase in the polymerisation of the silicate network of the C-S-H (increase in the length of the chains) has been recorded by Jennings [14,15], while dimeric silicate species predominate in the C-S-H during the first 24 h and for W/C=0.24-0.25, at room temperature [16]. In addition, a link between changes in the C-S-H gel structure and the deformations of cement pastes has also been pointed out in the literature: a temperature rise reduces shrinkage in partic- ular because high temperature pre-shrinks the low-density C-S-H (see Refs.…”

Section: Temperature Effects On Volumetric Autogenous Shrinkage-propomentioning

confidence: 87%

Autogenous deformations of cement pastes

Baroghel-Bouny

Mounanga

Khelidj

et al. 2006

Cement and Concrete Research

165

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A micro-macro experimental study has been performed, from the end of mixing up to 2 years, on a set of plain cement pastes prepared with the same type I ordinary Portland cement (OPC) and various water-to-cement ratios (W/C), and cured at various constant temperatures. In this part I of the paper, volumetric autogenous shrinkage has been analysed in relation to various parameters characterizing the hydration process: chemical shrinkage, degree of hydration of the cement, Ca(OH) 2 content and Vicat setting times, within the early-age period (V24 h). The effects of the curing temperature (ranging from 10 up to 50 8C) have in particular been investigated. Its effects recorded on both the rate and the magnitude of volumetric autogenous shrinkage vs. time have pointed out the irrelevance of the usual maturity concept to describe such phenomenon within the whole early-age period. An improved maturity concept has hence been proposed. It is based on separating the early-age period in different phases and on using chemical shrinkage data for the calculation of the apparent activation energy applied to the prediction of autogenous deformations occurring after the setting period. Furthermore, micro-macro relationships have been pointed out, illustrating in particular the determining role of Ca(OH) 2 .

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“…An LDH-type phase could also exist in the plain AAS pastes, but it generally occurs as a near micro-scale combination with C-S-H gel [30,[39][40]. The addition of GO increases the size of the LDHs and promotes the growth of crystals.…”

Section: Microstructural Investigationsmentioning

confidence: 99%

Effect of graphene oxide on the mechanical properties and the formation of layered double hydroxides (LDHs) in alkali-activated slag cement

Zhu

Kang

Yang

et al. 2017

Construction and Building Materials

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Highlights:(1) Graphene Oxide (GO) caused a significant reduction in fluidity and a slight decrease in compressive strength of AAS mortars.(2) The flexural strength of hardened mortars were improved by adding GO.(3) Layered double hydroxides (LDHs) were observed and confirmed in GO-added AAS system. AbstractDue to its high aspect ratio and outstanding tensile strength, graphene oxide (GO) can dramatically reduce the brittleness of cement-based materials. In this paper, GO nanosheets were successfully synthesised using the modified Hummers' method. Effects of the GO on the fluidity, mechanical properties of alkali-activated slag (AAS) mortars and the microstructure of the AAS pastes were studied.It is found that addition of the GO caused a significant reduction in fluidity and a slight decrease in the compressive strength of the hardened mortars. However, the GO improved the flexural strengths by 20% with a dosage of 0.01 wt. % after 7 days. Large-scale layered double hydroxides (LDHs) were observed using SEM, the compositions of which were identified and EDS and XRD. A possible mechanism of the formation of LDHs in the GO-AAS system is proposed. Due to the Mg 2+ /Al 3+ decomposed from the slag and the Al(OH)4 -formed in the high pH condition in the GO-AAS system, the reaction pathway of LDHs 2 can be regarded as a , This research provides a further understanding of the effect of graphene oxide which has a potential application of GO in AASC.

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The nature of C-S-H in hardened cements

Cited by 870 publications

References 57 publications

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

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

Autogenous deformations of cement pastes

Effect of graphene oxide on the mechanical properties and the formation of layered double hydroxides (LDHs) in alkali-activated slag cement

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