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Karen Scrivener

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Publications associées (271)

Fe-containing phases in hydrated cements

Karen Scrivener, Belay Zeleke Dilnesa, Barbara Lothenbach

In this study synchrotron X-ray absorption spectroscopy (XAS) has been applied, an element specific technique which allows Fe-containing phases to be identified in the complex mineral mixture of hydrated cements. Several Fe species contributed to the overa ...

Pergamon-Elsevier Science Ltd2014

Reaction kinetics of dolomite and portlandite

Karen Scrivener, Xinyu Zhang

The reactions of dolomite with portlandite have been studied at well-spaced temperatures between 20 degrees C and 85 degrees C using XRD Rietveld, TG and SEM methods. The results show quantitatively the faster rates of reaction at higher temperature. Isoth ...

Pergamon-Elsevier Science Ltd2014

Use of X-ray diffraction to quantify amorphous supplementary cementitious materials in anhydrous and hydrated blended cements

Karen Scrivener, Ruben Anton Snellings

The content of individual amorphous supplementary cementitious materials (SCMs) in anhydrous and hydrated blended cements was quantified by the PONKCS [1] X-ray diffraction (XRD) method. The analytical precision and accuracy of the method were assessed thr ...

Pergamon-Elsevier Science Ltd2014

Understanding the Filler Effect on the Nucleation and Growth of C-S-H

Karen Scrivener, Elise Marie Jeanne Berodier

The filler effect, due to the physical presence of mineral additions in cement, is mainly known to accelerate the hydration of the clinker component. Previously, this was attributed to the surface of the filler providing nucleation sites for C-S-H as there ...

Wiley-Blackwell2014

Effect of Magnesium and Zinc Ions on the Hydration Kinetics of C3S

Marco Cantoni, Karen Scrivener, Amélie Bazzoni, Qiao Wang

Impure tricalcium silicate (C3S) in portland cement may contain various foreign ions. These ions can stabilize different polymorphs of C3S at room temperature and may affect its reactivity. In this paper, the effects of magnesium and zinc on the polymorph ...

Wiley-Blackwell2014

Phase compositions and equilibria in the CaO-Al2O3-Fe2O3-SO3 system, for assemblages containing ye'elimite and ferrite Ca-2(Al,Fe)O-5

Karen Scrivener

Phase equilibria in the CaO-Al2O3-Fe2O3-SO3 system have been studied, mainly at 1325 degrees C. In particular the solid solution compositions of ye'elimite Ca-4(Al6O12)SO4 and brownmillerite (C-2(A,F)) phases have been analysed and used to estimate the com ...

Pergamon-Elsevier Science Ltd2013

On the relevance of volume increase for the length changes of mortar bars in sulfate solutions

Karen Scrivener, Wolfgang Kunther, Barbara Lothenbach

The ingress of sulfate ions into cementitious materials leads to the formation of ettringite, gypsum and other phases. The increase in solid volume through the formation of these phases is often assumed to be the only reason for expansion. In this paper we ...

Pergamon-Elsevier Science Ltd2013

The morphology of C-S-H: Lessons from H-1 nuclear magnetic resonance relaxometry

Karen Scrivener

H-1 nuclear magnetic resonance has been applied to cement pastes, and in particular calcium silicate hydrate (C-S-H), for the characterisation of porosity and pore water interactions for over three decades. However, there is now renewed interest in the met ...

Pergamon-Elsevier Science Ltd2013

Numerical Simulation of Porosity in Cements

Karen Scrivener, Shashank Bishnoi, Quang Huy Do

The pores in cementitious materials, their sizes and connectivity have an important influence on the durability of concrete. Several microstructural models have been developed to simulate the three-dimensional pore network in cement pastes. In this article ...

Springer Netherlands2013

The Effect of Aluminum in Solution on the Dissolution of Amorphous Silica and its Relation to Cementitious Systems

Karen Scrivener, Theodor Alexandre Emmanuele Chappex

One of the most serious causes of degradation of concrete is the alkalisilica reaction. Amorphous silicates present in certain aggregates react with the alkaline pore solution of the concrete to form a gel, which absorbs water and swells, leading to the ex ...

Wiley-Blackwell2013

Use of bench-top NMR to measure the density, composition and desorption isotherm of C-S-H in cement paste

Karen Scrivener, Arnaud Charles Albert Muller

H-1 nuclear magnetic resonance (NMR), supported by a measurement of the degree of hydration using X-ray diffraction, has been used to fully characterise the nano-scale porosity and composition of calcium-silicate-hydrate (C-S-H), the active component of ce ...

Elsevier Science Bv2013

Densification of C-S-H Measured by H-1 NMR Relaxometry

Karen Scrivener, Arnaud Charles Albert Muller

The nanoscale morphology of, and pore water interactions in, calcium silicate hydrate (C-S-H), the active component of cement, remain uncertain. H-1 nuclear magnetic resonance (NMR) can fully characterize the nanoporosity of C-S-H in as-prepared material w ...

Amer Chemical Soc2013

Deterioration of mortar bars immersed in magnesium containing sulfate solutions

Karen Scrivener, Wolfgang Kunther, Barbara Lothenbach

Mortars prepared with a CEM I and a CEM III/B binder were investigated in different magnesium sulfate solutions. The main deterioration mechanism for the CEM I was expansion, while surface erosion was dominant for CEM III/B. The presence of sodium, potassi ...

Springer Verlag2013

Effect of temperature on the microstructure of calcium silicate hydrate (C-S-H)

Karen Scrivener, Emmanuel Gallucci, Xiuwei Zhang

Temperature affects the properties of concrete through its effect on the hydration of cement and its associated microstructural development. This paper focuses on the modifications to C-S-H induced by isothermal curing between 5 and 60 degrees C. The resul ...

Pergamon-Elsevier Science Ltd2013

Mechanism of expansion of mortars immersed in sodium sulfate solutions

Karen Scrivener, Cheng Yu, Wei Sun

The mechanisms behind the expansion of samples immersed in solutions containing sulfate ions have been controversial. Expansion is believed to originate in the formation of ettringite, but it is not possible to find any direct correlation between these two ...

Pergamon-Elsevier Science Ltd2013

A 3D lattice Boltzmann effective media study: understanding the role of C-S-H and water saturation on the permeability of cement paste

Karen Scrivener, Mohamad Zalzale

A 3D lattice Boltzmann model is developed and used to calculate the water and gas permeabilities of model cement pastes at different degrees of water saturation. In addition to permeable micron-sized capillary pores and impermeable solid inclusions, the la ...

Institute of Physics2013

Prediction of self-desiccation in low water-to-cement ratio pastes based on pore structure evolution

Karen Scrivener, Hui Chen, Pietro Lura

High-performance concrete is sensitive to early-age cracking, mainly due to its rapidly-developing autogenous shrinkage. Autogenous shrinkage and internal relative humidity (RH) decrease are direct consequences of the emptying of capillary pores due to cem ...

Pergamon-Elsevier Science Ltd2013

Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions

Karen Scrivener, Wolfgang Kunther, Barbara Lothenbach

This work investigates the influence of bicarbonate ions on the deterioration of cementitious material exposed to sulfate ions. Mortars based on a CEM I and on a CEM III/B cement were investigated. Experimental investigations were compared to thermodynamic ...

Pergamon-Elsevier Science Ltd2013

Interactions between alite and C(3)A-gypsum hydrations in model cements

Karen Scrivener, Alexandra Quennoz

This paper focuses on the interactions that occur between cement phases during early hydration, especially between the hydration of alite and C(3)A-gypsum. This study shows that alite reaction is accelerated in the presence of gypsum. This acceleration was ...

Pergamon-Elsevier Science Ltd2013

Hydration of C(3)A-gypsum systems

Karen Scrivener, Alexandra Quennoz

Hydration of C(3)A-gypsum systems with different gypsum additions was investigated in terms of the phase assemblage, kinetics and microstructural development. The second stage of the reaction, which begins after the depletion of gypsum, was of particular i ...

Pergamon-Elsevier Science Ltd2012

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