Provis, J.L. orcid.org/0000-0003-3372-8922 (2016) On the use of the Jander equation in cement hydration modelling. RILEM Technical Letters, 1. pp. 62-66.
Abstract
The equation of Jander [W. Jander, Z. Anorg. Allg. Chem. (1927) 163: 1-30] is often used to describe the kinetics of dissolution of solid cement grains, as a component of mathematical descriptions of the broader cement hydration process. The Jander equation can be presented as kt/R2 =[1-(1-α) (1/3) ]2 where k is a constant, t is time, R is the initial radius of a solid reactant particle, and α is the fractional degree of reaction. This equation is attractive for its simplicity and apparently straightforward derivation. However, the derivation of the Jander equation involves an approximation related to neglect of particle surface curvature which means that it is strictly not correct for anything beyond a very small extent of reaction. This is well documented in the broader literature, but this information has not been effectively propagated to the field of cement science, which means that researchers are continuing to base models on this erroneous equation. It is recommended that if the assumptions of diffusion control and unchanging overall particle size which lead to the selection of the Jander equation are to be retained, it is preferable to instead use the Ginstling-Brounshtein equation [A.M. Ginstling, B.I. Brounshtein, J. Appl. Chem. USSR (1950) 23: 1327-1338], which does correctly account for particle surface curvature without significant extra mathematical complication. Otherwise, it is possible (and likely desirable) to move to more advanced descriptions of particle-fluid reactions to account for factors such as dimensional changes during reaction, and the possibility of rate controlling influences other than diffusion.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 John Lloyd Provis. This work is licensed under a Creative Commons Attribution 4.0 International License. |
Keywords: | Modeling; Hydration; Shrinking core; Jander equation; Ginstling-Brounshtein equation |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 15 Nov 2016 13:20 |
Last Modified: | 15 Nov 2016 13:20 |
Published Version: | http://dx.doi.org/10.21809/rilemtechlett.2016.13 |
Status: | Published |
Publisher: | RILEM Publications SARL |
Refereed: | Yes |
Identification Number: | 10.21809/rilemtechlett.2016.13 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:107333 |