Chloride diffusion coefficient through porous materials : a disturbing parameter

Title: Chloride diffusion coefficient through porous materials : a disturbing parameter
Author(s): Pascale Bégué, Sylvie Lorente, Xavier Bourbon
Paper category : conference
Book title: 2nd International RILEM Symposium on Advances in Concrete through Science and Engineering
Editor(s): J. Marchand, B. Bissonnette, R. Gagné, M. Jolin and F. Paradis
Print-ISBN: 2-35158-003-6
e-ISBN: 2351580028
Publisher: RILEM Publications SARL
Publication year: 2006
Nb references: 11
Language: English

Abstract: Chloride diffusion is believed to be an indicator of durability for cement-based materials. The diffusion test consists of sandwiching a sample of material between two compartments, and applying a chloride concentration gradient between the two faces of the material so that the transport is one-dimensional. From the chloride flux measured in steady state, and the Fick’s law of diffusion the chloride diffusion coefficient is calculated. This very well known experiment convinced some researchers that the chloride diffusion coefficient is concentration dependant.
The objective of this paper is to demonstrate that this assumption is not correct. The experiments were made on a manufactured ceramic of TiO2 . Such a material was chosen for the absence of interactions between the solid phase and chloride, allowing therefore short term experiments. Through a model based on a multi ionic description of the transfers the importance of the membrane potential in chloride diffusion is stressed. It is shown that the chloride diffusion coefficient is unique for a given material.

Keywords: cementitious matrials, chloride diffusion, model, multi-species approach

Online publication: 2006-08-02
Classification: 3.1 Theme 1: Numerical Models: from Microstructure to Transport Properties and Durability
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580028.017