A model for dissolution of CaO-SiO2-H2O gel at Ca/Si &gt; 1

Rahman, Md. Mazibur; Nagasaki, Shinya; Tanaka, Satoru

doi:10.1016/s0008-8846(99)00092-7

Cited by 34 publications

(14 citation statements)

References 22 publications

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“…(Börjesson et al, 1997) used an non-ideal solid solution of CH -CaH 2 SiO 4 for 1<C/S≤1.43, based on data from (Kalousek, 1952). (Rahman et al, 1999) proposed a similar model as (Börjesson et al, 1997), within the C/S range from 1. to 1.5. (Kersten, 1996) proposed a non-ideal binary solid solution CH -CaHSiO 3.5 ·H2O based on the experimental data from (Greenberg and Chang, 1965) and (Fujii and Kondo, 1981).…”

Section: Carbonation Of Calcium Silicate Hydrates (C-s-h) 31mentioning

confidence: 99%

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

Shen

2013

International Journal of Greenhouse Gas Control

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RésuméUn modèle de transport réactif est proposé pour simuler la réactivité des matériaux à base de ciment en contact avec une saumure saturée en CO 2 et/ou le CO 2 supercritique (CO 2 sc) dans les conditions de stockage géologique du CO 2 . Un code a été développé pour résoudre simultanément le transport et la chimie par une approche globale couplée, compte tenu de l'effet de la température et de la pression.La variabilité des propriétés du CO 2 sc avec la pression et la température, telles que la solubilité dans l'eau, la densité et la viscosité sont pris en compte. On suppose que tous les processus chimiques sont en équilibre thermodynamique. Les réactions de dissolution et de précipitation de la portlandite (CH) et Ce modèle est en mesure de simuler les processus de carbonatation des matériaux à base de ciment, dans des conditions à la fois saturés et insaturés, dans une large plage de concentration de CO 2 , de température et de pression. Plusieurs expériences, rapportées dans la littérature, sont simulées en utilisant divers types de conditions aux limites: (i) solutions saturées ou non en CO 2 et carbonate de calcium, (ii) gas supercritique de CO 2 . Les prédictions sont comparées avec les observations expérimentales. Certains II phénomènes observés expérimentalement peuvent être également expliqués par le modèle. Mots-clés:Carbonatation, CO 2 supercritique, Transports, Ciment, C-S-H, Décalcification, Pression, Température, Stockage du CO 2 . AbstractA reactive transport model is proposed to simulate the reactivity of cement based material in contact with CO 2 -saturated brine and supercritical CO 2 (scCO 2 ) under CO 2 geological storage conditions. This code is developed to solve simultaneously transport and chemistry by a global coupled approach, considering the effect of temperature and pressure.The variability of scCO 2 properties with pressure and temperature, such as solubility in water, density and viscosity are taken into account. It is assumed that all chemical processes are in thermodynamical equilibrium. Dissolution and precipitation reactions for portlandite (CH) and calcite (CC) are described by mass action laws and threshold of ion activity products in order to account for complete dissolved minerals. A chemical kinetics for the dissolution and precipitation of CH and CC is introduced to facilitate numerical convergence. One properly chosen variable is able to capture the precipitation and dissolution of the relevant phase. A generalization of the mass action law is developed and applied to calcium silicate hydrates (C-S-H) to take into account the continuous variation (decrease) of the Ca/Si ratio during the dissolution reaction of C-S-H. The changes in porosity and microstructure induced by the precipitation and dissolution reactions are also taken into account.Couplings between transport equations and chemical reactions are treated thanks to five mass balance equations written for each atom (Ca, Si, C, K, Cl) as well as one equation for charge balance and one for the total mass. Ion tran...

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Section: Carbonation Of Calcium Silicate Hydrates (C-s-h) 31mentioning

confidence: 99%

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

Shen

2013

International Journal of Greenhouse Gas Control

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“…The interpretation of solubility data for C-S-H systems has often been based on the assumption of solid solution formation between defined C-S-H phase end-members [41,42,45], between a C-S-H phase and portlandite [46,47], or for low C/S systems between a calcium silicate hydrate phase and amorphous silica [24,41,45]. The experiments reported here have focused on freshly prepared low C/S systems subjected to dynamic leaching.…”

Section: C-s-h Gels Leaching Resultsmentioning

confidence: 99%

Leaching behaviour of low Ca:Si ratio CaO–SiO2–H2O systems

Swanton¹,

Heath²,

Clacher³

2016

Cement and Concrete Research

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“…[6][7][8] Such pragmatic models are neither based on strong thermodynamic theory nor readily extendable to cover elevated temperatures or variations in solid phase composition, but still the Berner 3 model and its variants have been the most widely used due to their simplicity. More thermodynamically rigorous solid solution aqueous solution based models [9][10][11][12] have been applied to Ca/Si ratios .1?0 in the C-S-H gel but are only reliable at room temperature. True Gibbs energy based models, such as that reported here, aim for greater flexibility and rely more on thermodynamic realism than earlier models, accounting for all Ca/Si ratios expected in the C-S-H gel and extending temperature limits.…”

Section: Previous Workmentioning

confidence: 99%

Thermodynamic modelling of phase equilibria in cement systems: multiple sublattice model for solids in equilibrium with non-ideal aqueous phase

Davies

Gisby

Dinsdale

et al. 2014

Advances in Applied Ceramics

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The thermodynamics of the CaO-SiO 2 -H 2 O (C-S-H) gel phase present in cement systems has traditionally been modelled in terms of one or more stoichiometric solid phases. We present a model for the C-S-H gel phase based on non-ideal solution of ions and/or molecular species on a number of sublattices similar to that used extensively in National Physical Laboratory's MTDATA software for modelling oxides and alloy phases. In application to the C-S-H system, aqueous phase compositions are represented within experimental uncertainties, and measured pH values are predicted exceptionally well although not included in the model parameterisation. Extensions to the base C-S-H model to account for the presence of Al 2 O 3 , modelling of the analogous M-S-H phase in MgO containing systems and an application to nuclear waste disposal technology where the portioning of uranium between the gel, aqueous and other phases is calculated, are also discussed.

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A model for dissolution of CaO-SiO2-H2O gel at Ca/Si > 1

Cited by 34 publications

References 22 publications

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

Leaching behaviour of low Ca:Si ratio CaO–SiO2–H2O systems

Thermodynamic modelling of phase equilibria in cement systems: multiple sublattice model for solids in equilibrium with non-ideal aqueous phase

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