Abstract
Deterioration of concrete structures subjected to aggressive water is often characterized by the leaching of calcium from hydrates. Since calcium leaching is a nonlinear phenomenon, which is influenced by a wide range of parameters, the residual service life of the structures affected by such deterioration cannot be predicted satisfactorily on the basis of experimental results alone. In order to provide more fundamental information on this phenomenon, a numerical model was developed. The model considers the thermodynamic equilibrium between the pore solution and the various hydrated phases. In addition, the deterioration mechanism is treated from a macroscopic point of view. This model has been first validated on cement paste samples leached by deionised water. Second, extension to other kinds of environment and materials was done by considering modification of the chemical equilibrium between pore solution, and solid hydrates.
Résumé
La détérioration des structures en béton sollicitées par des eaux agressives est généralement caractérisée par la lixiviation du calcium, principal constituant des hydrates du ciment. Ce phénomène étant non-linéaire et influencé par de nombreux paramètres, la durée de vie résiduelle des structures soumises à ce type de détérioration ne peut pas être déterminée sur la seule base de résultats expérimentaux. Le modèle numérique développé dans cet article permet de fournir des enseignements plus fondamentaux. Ce modèle tient compte de l'équilibre thermodynamique entre la solution interstitielle présente dans les pores de la pâte de ciment et les différents hydrates qui la constitue. De plus, le mécanisme de détérioration est décrit à l'aide d'une approche macroscopique. Ce modèle est tout d'abord validé sur la base d'échantillons de pâte de ciment lixibiée au contact de l'eau pure. Ensuite, l'extension à d'autres types de conditions environmentales et de matériaux a été effectuée en considérant une modification de l'équilibre chimique entre la solution interstitielle et les hydrates.
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Gérard, B., Le Bellego, C. & Bernard, O. Simplified modelling of calcium leaching of concrete in various environments. Mat. Struct. 35, 632–640 (2002). https://doi.org/10.1007/BF02480356
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DOI: https://doi.org/10.1007/BF02480356