Probing Microstructure Evolution during the Hardening of Gypsum by Proton NMR Relaxometry

Jaffel, Hamouda; Korb, Jean-Pierre; Ndobo-Epoy, Jean-Philippe; Morin, Vincent; Guicquero, Jean-Pierre

doi:10.1021/jp058276m

Cited by 32 publications

(24 citation statements)

References 23 publications

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“…A matrix pore network characterized by two relaxation time peaks was observed previously in other gypsum-based materials [56,60]. The dominant peak is centred on a pore radius R 20 µm, which is consistent with the mean pore size obtained from the SEM images.…”

Section: Resultssupporting

confidence: 89%

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

Song¹,

Mitchell²,

Jaffel³

et al. 2011

J. Phys. D: Appl. Phys.

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In this paper we investigate both capillary water imbibition and the sorptivity of aerated gypsum plaster, and how these sorption characteristics are related to the pore structure of the material. These characteristics are examined by monitoring mass change using the conventional gravimetric method and by obtaining water content profiles using non-destructive magnetic resonance imaging (MRI) techniques during capillary imbibition of water. Here, three different gypsum samples are investigated: one non-aerated reference gypsum sample and two aerated gypsum samples produced with different volumetric air fractions. The capillary water absorption into the reference sample follows t 1/2 kinetics (Fickian diffusion), where t is the time of ingress. However, in the aerated gypsum samples there are deviations from t 1/2 kinetics. The MRI results show unambiguously that two wetting fronts advance through the aerated structure; an observation that cannot be made from the gravimetric data alone. The water content profiles of the aerated gypsum samples are therefore analysed by treating them as the sum of two separate absorption processes using sharp front analysis. The capillary water absorption properties of this material are well described as a parallel combination of fast absorption into fine matrix pores and slow absorption into a modified structure of matrix pores inter-connected to air voids introduced into the slurry by aeration.

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Section: Resultssupporting

confidence: 89%

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

Song¹,

Mitchell²,

Jaffel³

et al. 2011

J. Phys. D: Appl. Phys.

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“…Polycrystalline cast gypsum objects are known to be highly porous (typically 36À61% by Hg porosimetry) at the water: plaster mixing ratios typically used to retain fluidity. 40 The surface composition of gypsum relative to resin was approximately 1:1 for all samples apart from those treated with tartaric acid where the ratio was 1:1.5. Further details are given in the Supporting Information, section 2, which also details λ values for each of the materials studied (see also Table 1).…”

Section: ' Theory and Kinetic Modelingmentioning

confidence: 88%

Dissolution Kinetics of Polycrystalline Calcium Sulfate-Based Materials: Influence of Chemical Modification

Fisher

Mbogoro

Snowden

et al. 2011

ACS Appl. Mater. Interfaces

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Using a channel flow cell (CFC) system, the dissolution kinetics of polycrystalline gypsum-based materials have been examined with the aim of understanding their interaction with water, a property that limits the applications of the material in many situations. ICP (inductively coupled plasma) analysis of elemental concentrations in solution as a function of time yields surface fluxes by using a finite element modeling approach to simulate the hydrodynamic behavior within the CFC. After correction for surface roughness, a value for the intrinsic dissolution flux into water of pure polycrystalline gypsum, CaSO(4).2H(2)O, of 1.1 (±0.4) × 10(-8) mol cm(-2) s(-1) has been obtained. The addition of known humid creep inhibitors to the gypsum samples, including boric acid, tartaric acid and 3,4,5-trihydroxybenzoic acid (gallic acid), was found to have little measurable effect on the dissolution kinetics of gypsum: all yielded dissolution fluxes of 1.4 (±0.6) × 10(-8) mol cm(-2) s(-1). However, trisodium trimetaphosphate (STMP) was found to have a small detectable inhibitory effect relative to pure gypsum yielding a flux of 7.4 (±2.0) × 10(-9) mol cm(-2) s(-1). The data strongly suggest that models for humid creep inhibition that involve dissolution-crystallization of gypsum crystallites are less likely than those that involve a hindered ingress of water into the gypsum matrix. For comparison, composite materials that comprised of calcium sulfate anhydrite (CaSO(4)) crystallites bound by a polyphosphate matrix were also studied. For some of these samples, Ca(2+) surface fluxes were observed to be ∼1 order of magnitude lower than values for polycrystalline gypsum control substrates, suggesting a useful way to impart water resistance to gypsum-based materials.

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“…Such measurements have been widely applied to the study of fluids confined to heterogeneous porous media, and provide information on the effects of pore structure and surface interactions on molecular dynamics. Representative fields of investigation include rock and shale wettability studies for the hydrocarbon recovery industry, and the characterisation of plaster and cement paste hydration kinetics …”

Section: Introductionmentioning

confidence: 99%

Direct Correlation between Adsorption Energetics and Nuclear Spin Relaxation in a Liquid‐saturated Catalyst Material

et al. 2018

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The ratio of NMR relaxation time constants T 1 / T 2 provides a non-destructive indication of the relative surface affinities exhibited by adsorbates within liquid-saturated mesoporous catalysts. In the present work we provide supporting evidence for the existence of a quantitative relationship between such measurements and adsorption energetics. As a prototypical example with relevance to green chemical processes we examine and contrast the relaxation characteristics of primary alcohols and cyclohexane within an industrial silica catalyst support. T 1 / T 2 values obtained at intermediate magnetic field strength are in good agreement with DFT adsorption energy calculations performed on single molecules interacting with an idealised silica surface. Our results demonstrate the remarkable ability of this metric to quantify surface affinities within systems of relevance to liquid-phase heterogeneous catalysis, and highlight NMR relaxation as a powerful method for the determination of adsorption phenomena within mesoporous solids.

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Probing Microstructure Evolution during the Hardening of Gypsum by Proton NMR Relaxometry

Cited by 32 publications

References 23 publications

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

Dissolution Kinetics of Polycrystalline Calcium Sulfate-Based Materials: Influence of Chemical Modification

Direct Correlation between Adsorption Energetics and Nuclear Spin Relaxation in a Liquid‐saturated Catalyst Material

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