MOISTURE TRANSPORT REVIEW

VI-1 1.0 INTRODUCTION VI-1 2.0 BACKGROUND VI-2 2.1 Morphology and Terminology VI-2 2.2 Mechanisms of Moisture Transport VI-3 2.2.1 Flow-Inducing Potentials VI-3 2.2.2 Equilibrium Pressure Conditions VI-4 2.3 Modeling Formulations VI-4 3.0 MOISTURE TRANSPORT IN POROUS MEDIA VI-5 3.1 Transport Equations VI-5 3.2 Model Parameters VI-6 3.2.1 Relative Permeability as a Function of Saturation VI-6 3.2.2 Hydraulic Diffusivity as a Function of Water Content VI-7 3.2.3 Hydraulic Diffusivity as a Function of Relative Humidity VI-8 3.3 Selected Model Parameter Measurements VI-11 3.3.1 Saturated Hydraulic Conductivity (Permeability) VI-11 3.3.2 Porosity and Pore Size Distribution Measurements VI-14 3.3.3 Measurement of Hydraulic Diffusivity VI-15 3.4 Qualitative Tests VI-16 4.0 MOISTURE TRANSPORT THROUGH FRACTURED MEDIA VI-16 4.1 Role of Fractures in Moisture Transport VI-17 4.1.1 Modeling Approaches for Fractured Media VI-19 5.0 OTHER TRANSPORT MODELS VI-21 5.1 Pore-scale Models VI-21 5.2 Lattice-Boltzmann Methods VI-22 Moisture Transport Review VI-iv 6.0 CHALLENGES AND OPPORTUNITIES VI-23 7.0 REFERENCES VI-24 8.0 APPENDIX VI-31 CONTENTS (contd) Page No. Moisture Transport Review VI-v LIST OF FIGURES Page No. Figure 1. Observed Hydraulic Diffusivity (DRH/D100%) as a Function of Relative Humidity (modifi ed from Bazant and Najjar, 1971). VI-10 Figure 2: Illustration of Moisture Transport Regimes with Respect to Liquid Saturation (modifi ed from Garrabrants and Kosson 2003). VI-10 Figure 3: Permeability Test Apparatus (CRD 1992). VI-11 Figure 4: Triaxial Permeability Test Apparatus (CRD 1992). VI-12 Figure 5: Steps in the Dynamic Pressurization Method (Scherer 2006). VI-13 Figure 6: Critical Pore Radius (i.e., continuous pore diameter) and Threshold Radius from MIP Data (Nokken and Hooton 2006; Nokken and Hooton 2008). VI-14 Figure 7: Water Content Profi les Measured using NMR Techniques (Pel, Brocken et al. 1996) VI-16 Figure 8: Hydraulic Conductivity of a Saturated Crack as a Function of Aperture. VI-18 Figure 9: Effective Unsaturated Hydraulic Conductivity Derived for a Hypothetical Cracked Concrete based on Or and Tuller (2000). VI-20