Title:
Validation of Mualem’s Conductivity Model and Prediction of Saturated Permeability from Sorptivity
Author(s):
Craig Leech, David Lockington, R. Doug Hooton, Graham Galloway, Gary Cowin, and Peter Dux
Publication:
Materials Journal
Volume:
105
Issue:
1
Appears on pages(s):
44-51
Keywords:
absorption; adsorption; durability; nuclear magnetic resonance; permeability; pore size distribution; transport properties
DOI:
10.14359/19206
Date:
2/1/2008
Abstract:
Advanced modeling of unsaturated water and contaminant transport in concrete requires knowledge of the unsaturated conductivity (permeability) function and the water retention curve. An assumption of simple Fickian diffusion is not sufficient due to the nonlinear water and contaminant fluxes. The Van Genuchten-Mualem conductivity model, widely used in describing hydraulic properties of soils, is validated by predicting experimental moisture content profiles obtained by nuclear magnetic resonance during simple absorption experiments with concrete cylinders. A new tortuosity parameter is suggested. Analytical methods are extended based on the Van Genuchten-Mualem model, to provide a means of estimating the saturated permeability from the much simpler sorptivity experiment. The predicted permeability is similar to the long-term experimental permeability. This suggests that only the very long-term saturated permeability is suitable for describing unsaturated moisture flux.