Title:
Determination of the Effective Chloride Diffusion Coefficient in Concrete via a Gas Diffusion Technique
Author(s):
Alfarabi Sharif, K. F. Loughlin, A. K. Azad, and C. M. Navaz
Publication:
Materials Journal
Volume:
94
Issue:
3
Appears on pages(s):
227-233
Keywords:
diffusion; effective diffusion coefficient; porosity;
static diffusion cell;
DOI:
10.14359/303
Date:
5/1/1997
Abstract:
A new experimental technique based on gas diffusion through a thin sample specimens is presented to evaluate the effective chloride diffusion ion in concrete. The counterdiffusion of two gases, helium and nitrogen, through a concrete disc is used to establish the porosity-to-tortuosity ratio (e/t) of the concrete. From measurements of the porosity via porosimetry, the tortuosity of the concrete can be determined. The effective chloride ion diffusion in concrete is a function of (e/t) ratio and the diffusion coefficient of chloride ion in water which is a known value. The test takes 3 to 4 hours to complete. Excellent results were obtained when correlated with the conventional diffusional measurement techniques for different water-cement ratios and cement content.