A new view on the kinetics of tricalcium silicate hydration

Nicoleau, Luc; Nonat, André

doi:10.1016/j.cemconres.2016.04.009

Cited by 137 publications

(59 citation statements)

References 50 publications

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“…40,[54][55][56] In the absence of PCEs, the rate-limiting step of cement hydration seems to be dissolution, as proposed by Nicoleau et al 54 following the evolution of saturation index during hydration. Very importantly also, the activation energy of cement hydration is the same as that of tricalcium silicate dissolution.…”

Section: Mechanistic Origin Of the Silicate Hydration Delaymentioning

confidence: 99%

“…61,62 This was first ascertained in geochemistry and has recently gained considerable attention in cement research. 40,54,58 The culprit of this theory is that dissolution pits play an important role in creating new kink sites, thereby increasing the dissolution rate that predominantly takes place through step retreat from those kinks until a steady state is reached. With respect to this study, the most noteworthy aspect is that compounds adsorbing at kinks are particularly detrimental to dissolution as they not only decrease the number of steps able to retreat, but also likely block the retreat of subsequent steps.…”

Section: Mechanistic Origin Of the Silicate Hydration Delaymentioning

confidence: 99%

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Molecular and submolecular scale effects of comb‐copolymers on tri‐calcium silicate reactivity: Toward molecular design

Marchon

Juilland²,

Gallucci³

et al. 2017

J Am Ceram Soc

121

109

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The impact of organic compounds on the processing and reactivity of inorganic materials has been a source of inspiration for materials scientists for decades and continues to trigger novel and innovative applications in a broad range of disciplines. However, molecular design of such compounds to reach targeted properties remains challenging, particularly for reactive and multicomponent systems. This outstanding challenge is met here by combining a model cement, hosting different coupled reactions of dissolution, nucleation and growth, together with combcopolymers that offer large and well-controlled variations of their molecular architecture. We show that silicate reactivity is affected by a combination of molecular and submolecular scale effects of these polymers. The first can be described by scaling laws from polymer physics, whereas the second involves specific chemical interactions. In particular, the ability of these polymers to hinder dissolution appears to be crucial, something for which strong experimental evidence is provided. K E Y W O R D Scalcium silicate,

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Section: Mechanistic Origin Of the Silicate Hydration Delaymentioning

confidence: 99%

Section: Mechanistic Origin Of the Silicate Hydration Delaymentioning

confidence: 99%

Molecular and submolecular scale effects of comb‐copolymers on tri‐calcium silicate reactivity: Toward molecular design

Marchon

Juilland²,

Gallucci³

et al. 2017

J Am Ceram Soc

121

109

View full text Add to dashboard Cite

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“…In this process of dissolution and precipitation, the silicate monomer is dissolved from C 3 S and defective sheets of tetrahedral SiO 4 4− are formed through silicate polymerization. The molar ratio of Ca to Si (Ca/Si) and the chain length of C–S–H change correspondingly due to silicate polymerization [8,10]. The growth rate of C–S–H has been shown to depend on the mechanism of C 3 S hydration kinetics in the acceleration period.…”

Section: Introductionmentioning

confidence: 99%

“…The early age C 3 S hydration process has been studied by many characterization techniques, including calorimetry [8,11,12,13], in situ X-ray diffraction [14], X-ray photoelectron spectroscopy (XPS) [10], electron microscopy [1,15], and in situ neutron scattering [6]. However, the methods described above are used for bulk analysis and are limited when providing local morphological and atomic-binding structural information about the hydration products.…”

Section: Introductionmentioning

confidence: 99%

In Situ Soft X-ray Spectromicroscopy of Early Tricalcium Silicate Hydration

et al. 2016

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The understanding and control of early hydration of tricalcium silicate (C3S) is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C3S at an early stage of hydration. In situ C3S hydration in a wet cell, beginning with induction (~1 h) and acceleration (~4 h) periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period after 15 h of curing. Analysis of the near-edge X-ray absorption fine structure showed that the Ca binding energy and energy splitting of C3S changed rapidly in the early age of hydration and exhibited values similar to calcium silicate hydrate (C–S–H). The formation of C–S–H nanoseeds in the C3S solution and the development of a fibrillar C–S–H morphology on the C3S surface were visualized. Following this, silicate polymerization accompanied by C–S–H precipitation produced chemical shifts in the peaks of the main Si K edge and in multiple scattering. However, the silicate polymerization process did not significantly affect the Ca binding energy of C–S–H.

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“…This is far less obvious for dissolution since the dissolving surface area S d is expected to decrease with the shrinking of the dissolving grains, implying that sufficient increase in under-saturation should produce equivalent increase in S d •R int (R int is the interfacial dissolution rate). However, this is not observed, as under-saturation hardly changes [54] over this interval, which implies an increase in either the number of dissolution sites or their surface area. The dissolution theory as introduced above offers ways to envisage the increase of dissolving surface, even at low under-saturation; for example, via the activation of kinks in the vicinity of screw-dislocations: their dissolution and expansion in the capillaries of hollow cores (Figure 4a.ii) would increase the dissolving surface and the overall dissolution rate as a consequence.…”

Section: Acceleration Regimementioning

confidence: 84%