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Computers and Concrete
  Volume 11, Number 3, March 2013, pages 201-222
DOI: http://dx.doi.org/10.12989/cac.2013.11.3.201
 


Coupled diffusion of multi-component chemicals in nonsaturated concrete
Nattapong Damrongwiriyanupap, Linyuan Li and Yunping Xi

 
Abstract
    A comprehensive simulation model for the transport process of fully coupled moisture and multispecies in non-saturated concrete structures is proposed. The governing equations of moisture and ion diffusion are formulated based on Fick's law and the Nernst-Planck equation, respectively. The governing equations are modified by explicitly including the coupling terms corresponding to the coupled mechanisms. The ionic interaction-induced electrostatic potential is described by electroneutrality condition. The model takes into account the two-way coupled effect of moisture diffusion and ion transport in concrete. The coupling parameters are evaluated based on the available experimental data and incorporated in the governing equations. Differing from previous researches, the material parameters related to moisture diffusion and ion transport in concrete are considered not to be constant numbers and characterized by the material models that account for the concrete mix design parameters and age of concrete. Then, the material models are included in the numerical analysis and the governing equations are solved by using finite element method. The numerical results obtained from the present model agree very well with available test data. Thus, the model can predict satisfactorily the ingress of deicing salts into non-saturated concrete.
 
Key Words
    deicing salts; chloride; concrete; coupled effect; Nernst-Planck equation
 
Address
Nattapong Damrongwiriyanupap: University of Phayao, Thailand; Linyuan Li: University of New Hampshire, USA; Yunping Xi: University of Colorado at Boulder, USA
 

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