What diffusion coefficient is used for chloride diffusion modeling?

Title: What diffusion coefficient is used for chloride diffusion modeling?
Author(s): M.R. de Rooij, R.B. Polder
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 9
Language: English

Abstract: Accurate service-life prediction of steel reinforced concrete structures is getting more and more attention. To date, the most advanced models on durability of concrete are found in the area of chloride-induced corrosion. When the depth of the reinforcement and the chloride load are known, simple diffusion equations can be used to calculate the time period until a certain chloride level has reached the reinforcement. However, even this straightforward approach already contains numerous problems and various sources of non-uniform information. For instance, the diffusion coefficient obtained by curve fitting Fick’s second law of diffusion to chloride profiles obtained from file data, depends on various decisions made during the curve fitting process. Furthermore, the curve fitting procedure results in a surface chloride content and an apparent diffusion coefficient couple. One cannot simply be separated from the other. A slightly different fit off the same field data results in a different diffusion coefficient and a different surface chloride content. Finally, both the surface chloride content and the apparent diffusion coefficient are time dependent, while in Fick’s law they are both assumed constant. In this article the above-mentioned examples will be further ex plained and discussed based on field data. Their consequences on service-life predictions are shown.

Online publication: 2004-03-25
Classification: Transport
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.047