Models for chloride ingress into concrete - From Collepardi to Today
Författare
Summary, in English
The first model to predict chloride ingress into concrete was presented by Collepardi in 1970, in Italian! That model was used for some 20 years for design of concrete structures before it was realized that the main parameter, the apparent chloride diffusion coefficient, is not a material property! Since then the Collepardi model has been significantly improved and developed into more or less sophisticated probabilistic models. Today we have numerous models for predicting chloride ingress but all of them have serious limitations that restrict the present use for long term predictions. The paper describes the history of developing chloride ingress models. An overview is given of the fundamental differences between various models, from those based on Fick's 2(nd) law and constant or time-dependent diffusion coefficients and surface chloride contents to those based on chloride transport equations with or without a multi-species approach. The three main limitations are shown to be the lack of understanding the time-dependency of the apparent chloride diffusion coefficients, and the lack of good long-term data, the chloride content increase with time close to the exposed surface and the difficulties in quantifying the boundary conditions for sophisticated ingress models.
Avdelning/ar
Publiceringsår
2008
Språk
Engelska
Sidor
36-42
Publikation/Tidskrift/Serie
Advances in Concrete Structural Durability, Proceedings of ICDCS2008, Vol 1 and 2
Dokumenttyp
Konferensbidrag
Förlag
Zhejiang University Press
Ämne
- Materials Engineering
Nyckelord
- interaction
- flux
- models
- chloride
- ingress
- binding
Conference name
International Conference on Durability of Concrete Structures
Conference date
2008-11-26 - 2008-11-27
Conference place
Hangzhou, China
Status
Published
ISBN/ISSN/Övrigt
- ISBN: 9787308063913