A moving-boundary model with stefan-signorini conditions to predict service life of concrete structures

Author(s): A. Muntean, M. Böhm, S.A. Meier
Paper category: Workshop
Book title: International RILEM Workshop on Integral Service Life Modelling of Concrete Structures
Editor(s): R.M. Ferreira, J. Gulikers, C. Andrade
Print ISBN: 978-2-35158-058-5
e-ISBN: 978-2-35158-090-5
Publisher: RILEM Publications SARL
Pages: 55 - 62
Total Pages: 8
Language: English

A natural way to describe fast-reaction-slow-diffusion scenarios in porous media such as carbonation in concrete is to employ a so-called moving-interface model. Such a model consists of a system of mass balance equations whose main feature is that it describes the carbonation reaction concentrated at the moving interface. The position of the moving interface is a priori unknown, and therefore it needs to be determined simultaneously with the concentrations of species involved. We address the question “How fast does the reaction penetrate the cement-based material?” by modelling the carbonation process as a moving one-phase problem with Stefan-Signorini conditions imposed across the moving interface. A numerical example illustrates the way the production and the fast precipitation of the reaction product may affect the motion of the interface. The geometry and the numerical input data are modelled on natural carbonation experiment settings for concrete with Portland cement, although the model should be applicable to more general situations. Despite some drastic simplifications, simulations show a good qualitative agreement with experimental data.

Keywords: Carbonation, Stefan-Signorini conditions, moving reaction interfaces, modelling

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00

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