Title:
Estimation of Effective Diffusion Coefficients and Non-Linear Binding Parameters of Chloride by Reverse Analysis of Chloride Profiles
Author(s):
K. Yamada, Y. Hosokawa, D. Mori, Y. Yamada, and B. Johannesson
Publication:
Symposium Paper
Volume:
234
Issue:
Appears on pages(s):
39-52
Keywords:
chloride; chloride binding; effective diffusion coefficient; EPMA; finite-difference method; numerical calculation; reverse analysis
DOI:
10.14359/15927
Date:
3/22/2006
Abstract:
Instead of the conventional method for evaluating an apparent diffusion coefficient of chloride ions (Cl-) from experimental Cl- concentration profile, this study introduces a novel method to estimate an effective diffusion coefficient (De) and non-linear binding parameters (a, b) of Cl- from a Cl- concentration profiles measured by electron probe micro analysis (EPMA). This estimation is made by the combination of numerical analysis by the finite-difference method of the non-linear diffusion equation and optimizing calculations. By using this method, De, a and b are estimated for several kinds of concrete having various type of cement and several levels of water-cement ratio. The estimated values of De show a positive linear relationship with values of De obtained by migration tests. The estimated values of a show a good correlation with the alumina content in cement as expected. These results indicate the validity of this method for estimating parameters required for predicting future Cl- concentration profiles.