Modeling Ion and Fluid Transport in Unsaturated Cement Systems for Isothermal Conditions

Published

January 1, 2005

Author(s)

E Samson, J Marchand, Kenneth A. Snyder, J J. Beaudoin

Abstract

A description of ionic transport in unsaturated porous materials due to gradients in the electro-chemical potential and the moisture content is developed by averaging the relevant microscopic transport equations over a representative volume element. The complete set of equations consist of a time-dependent equations for both the concentration of ionic species within the pore solution and the moisture content within the pore space. The electrostatic interactions are assumed to occur instantaneously and the resulting electrical potential satisfies Poisson'sequation. Using the homogenization technique, moisture transport due to both the liquid and vapor phases is shown to obey Richards' equation, and a precise definition of the moisture content is found. The final transport equations contain transport coefficients that can beunambiguously related to experimental quantities. The approach has the advantage of making the distinction between microscopic and bulk quantities explicit.

Citation

Concrete Science and Engineering

Volume

35

Issue

No. 1

Pub Type

Journals

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Keywords

building materials, concrete, diffusion, modeling, moisture, transport

Citation

Samson, E. , Marchand, J. , Snyder, K. and Beaudoin, J. (2005), Modeling Ion and Fluid Transport in Unsaturated Cement Systems for Isothermal Conditions, Concrete Science and Engineering, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860457 (Accessed October 27, 2025)