THI - a physical model for estimating the coupled transport of heat, moisture and chloride ions in concrete

Title: THI - a physical model for estimating the coupled transport of heat, moisture and chloride ions in concrete
Author(s): I. Petre-Lazar, L. Abdou, C. Franco, I. Sadri
Paper category : conference
Book title: 2nd International RILEM Workshop on Life Prediction and Aging Management of Concrete Structures
Editor(s): D.J. Naus
Print-ISBN: 2-912143-36-5
e-ISBN: 2912143780
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 51 - 69
Total Pages: 19
Nb references: 27
Language: English

Abstract: This contribution presents the THI model which has been developed at the R&D branch of EDF since 1999 for estimating the coupled in time evolution of temperature T(x,t), moisture W(x,t) and chloride profiles CCl(x,t). The model is a trade-off between the accuracy in describing the physical phenomena and the facility of use.
The THI model can be applied to concrete structures exposed varying temperature, moisture and chloride conditions (natural weathering, tidal and splash zones, de-icing salts) and is based on three semi-coupled transport equations;
The equation for the non-stationary heat transport is of Fourier type and provides the temperature (T) profile. The water (W) transport in the non-saturated concrete is governed by the second equation of the model. Separate terms are considered for the transport under moisture gradient and saturation pressure gradients (depending on the temperature gradients). The third equation describes the free chloride ions (CCl) transport by diffusion under the concentration gradient in the pore solution and by convection entrained by the liquid water movement. The ionic interactions and the chloride-matrix bond are taken into account by two parameters, respectively affecting the diffusion coefficient of the free ions in the pore solution.

Online publication: 2003-04-02
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143780.006