Silicate chain formation in the nanostructure of cement-based materials

Ayuela, Andrés; Dolado, Jorge S.; Campillo, I.; Miguel, Yolanda R. de; Erkizia, Edurne; Sánchez‐Portal, Daniel; Rubio, Ángel; Porro, A.; Echenique, Pedro M.

doi:10.1063/1.2796171

Cited by 65 publications

(57 citation statements)

References 27 publications

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“…In 2007, in a different study by Ayuela et al, it was proven by numerical simulations compared with NMR studies in hydrated cement pastes that only the 3n À 1 length chains are stable [45]. They corroborated that dimers are a result of growth mechanisms, whereas pentamers are created by merging process, as in the case of adding colloidal silica in the cement paste.…”

Section: Contemporary Computational Modelsmentioning

confidence: 63%

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A comprehensive review of the models on the nanostructure of calcium silicate hydrates

Papatzani

Paine

Calabria-Holley

2015

Construction and Building Materials

142

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Section: Contemporary Computational Modelsmentioning

confidence: 63%

“…Nonat [44] 2004 Surface chemistry of pastes or synthetic C-S-H Lameral and not entirely amorphous Thermodynamic calculations Ayuela et al [45] 2007 Local stability of chain is evaluated through the energies of the surrounding configurations 3n À 1 long silicate chains are stable Density functional theory…”

Section: Researchersmentioning

confidence: 99%

A comprehensive review of the models on the nanostructure of calcium silicate hydrates

Papatzani

Paine

Calabria-Holley

2015

Construction and Building Materials

142

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“…The surface of the C-S-H gel contains both silanol (Si-OH) and calcium hydroxide (Ca-OH) groups. 60,[62][63][64] These groups are both polar and have an active dipole moment (1.5 D) comparable to that of the water molecule (1.85 D). As dielectric spectroscopy is probing the fluctuations of dipole moments, our results could thus be an indication on that the fastest process is due to the reorientation of these hydroxyl groups (OH).…”

Section: Possible Molecular Origin Of the Fastest Relaxation In C-s-hmentioning

confidence: 99%

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

Monasterio

Jansson

Gaitero

et al. 2013

The Journal of Chemical Physics

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Articles you may be interested inCause of the fragile-to-strong transition observed in water confined in C-S-H gel In this study, the rotational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel with a water content of 22 wt.% was studied by broadband dielectric spectroscopy in broad temperature (110-300 K) and frequency (10 −1 -10 8 Hz) ranges. The C-S-H gel was used as a 3D confining system for investigating the possible existence of a fragile-to-strong transition for water around 220 K. Such transition was observed at 220 K in a previous study

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“…A realistic model for C-S-H that predicts a realistic C/S ratio thus remains a center piece of any model construction. Furthermore, quantitative information on the fractions of Si present in silicate tetrahedra with different connectivities is provided by 29 Si nuclear magnetic resonance (NMR) (8,9). Such studies have established that the dimer is the most predominant of all silicate species, with the linear pentamer as the second most abundant.…”

mentioning

confidence: 99%

A realistic molecular model of cement hydrates

Pellenq

Kushima²,

Shahsavari³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

807

533

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Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these characteristics of C-S-H define and modulate the physical and mechanical properties of this ''liquid stone'' gel phase. With the recent determination of the calcium/silicon (C/S ‫؍‬ 1.7) ratio and the density of the C-S-H particle (2.6 g/cm 3 ) by neutron scattering measurements, there is new urgency to the challenge of explaining these essential properties. Here we propose a molecular model of C-S-H based on a bottom-up atomistic simulation approach that considers only the chemical specificity of the system as the overriding constraint. By allowing for short silica chains distributed as monomers, dimers, and pentamers, this C-S-H archetype of a molecular description of interacting CaO, SiO2, and H2O units provides not only realistic values of the C/S ratio and the density computed by grand canonical Monte Carlo simulation of water adsorption at 300 K. The model, with a chemical composition of (CaO)1.65(SiO2)(H2O)1.75, also predicts other essential structural features and fundamental physical properties amenable to experimental validation, which suggest that the C-S-H gel structure includes both glass-like short-range order and crystalline features of the mineral tobermorite. Additionally, we probe the mechanical stiffness, strength, and hydrolytic shear response of our molecular model, as compared to experimentally measured properties of C-S-H. The latter results illustrate the prospect of treating cement on equal footing with metals and ceramics in the current application of mechanism-based models and multiscale simulations to study inelastic deformation and cracking.atomistic simulation ͉ mechanical properties ͉ structural properties B y mixing water and cement, a complex hydrated oxide called calcium-silicate-hydrate (C-S-H) precipitates as nanoscale clusters of particles (1). Much of our knowledge of C-S-H has been obtained from structural comparisons with crystalline calcium silicate hydrates, based on HFW Taylor's postulate that real C-S-H was a structurally imperfect layered hybrid of two natural mineral analogs (2) (4)]. While this suggestion is plausible in morphological terms, this model is incompatible with two basic characteristics of real C-S-H; specifically the calcium-tosilicon ratio (C/S) and the density. Recently, small-angle neutron scattering measurements have fixed the C/S ratio at 1.7 and the density at 2.6 g/cm 3 (1), values that clearly cannot be obtained from either tobermorite (C/S ϭ 0.83, 2.18 g/cm 3 ) or jennite (C/S ϭ 1.5 and 2.27 g/cm 3 ). From the standpoint of constructing a molecular model of C-S-H, this means that these crystalline minerals are not strict structural analogs. Here we adopt the perspective that the chemical composition of C-S-H is the most essential property in formulating a realistic molecular description. We show that once the C/S ratio is described...

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Silicate chain formation in the nanostructure of cement-based materials

Cited by 65 publications

References 27 publications

A comprehensive review of the models on the nanostructure of calcium silicate hydrates

A comprehensive review of the models on the nanostructure of calcium silicate hydrates

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

A realistic molecular model of cement hydrates

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