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On relationships between different chloride diffusion and/or migration coefficients in concrete



Title: On relationships between different chloride diffusion and/or migration coefficients in concrete
Author(s): T. Tang
Paper category : conference
Book title: Third International RILEM Workshop on Testing and Modelling Chloride Ingress into Concrete
Editor(s): C. Andrade and J. Kropp
Print-ISBN: 2-912143-48-9
e-ISBN: 2912143578
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 317 - 328
Total Pages: 12
Nb references: 29
Language: English


Abstract: This paper presents some theoretical considerations on relationships between different chloride diffusion and/or migration coefficients. A theory based on the multi-component transport was used to describe effective as well as apparent diffusion and migration coefficients. The theoretical equations clearly show that different test methods and test conditions result in different effective or apparent coefficients. The relations between different coefficients are therefore strongly dependent on many factors, such as the effect of counter electrical potential, the ratio of cation velocity to anion velocity, the ionic activity coefficient, and the friction coefficient. Under a non-steady state, the binding capacity is another factor influencing the relations between effective and apparent diffusion or migration coefficients. Some experimental data are used for verification of the theoretical equations. The sensitivity of test results to each influencing factor to the test results is theoretically analysed. The results show that the effective or apparent diffusion and migration coefficients calculated according to the theoretical equations are in very good agreement with those measured from different test methods. It has been shown, from both sensitivity analysis and experimental verifications, that the friction coefficient f is a key parameter that reflects the transport property of concrete. Different test methods result in similar friction coefficient.


Online publication: 2002-12-15
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143578.021