A Numerical Approach for NonLinear Moisture Flow in Porous Materials with Account to Sorption Hysteresis
(2010) In Transport in Porous Media 84(3). p.735754 Abstract
 A numerical approach for moisture transport in porous materials like concrete is presented. The model considers mass balance equations for the vapour phase and the water phase in the material together with constitutive equations for the mass flows and for the exchange of mass between the two phases. Historydependent sorption behaviour is introduced by considering scanning curves between the bounding desorption and absorption curves. The method, therefore, makes it possible to calculate equilibrium water contents for arbitrary relative humidity variations at every material point considered. The scanning curves for different wetting and drying conditions are constructed by using third degree polynomial expressions. The three coefficients... (More)
 A numerical approach for moisture transport in porous materials like concrete is presented. The model considers mass balance equations for the vapour phase and the water phase in the material together with constitutive equations for the mass flows and for the exchange of mass between the two phases. Historydependent sorption behaviour is introduced by considering scanning curves between the bounding desorption and absorption curves. The method, therefore, makes it possible to calculate equilibrium water contents for arbitrary relative humidity variations at every material point considered. The scanning curves for different wetting and drying conditions are constructed by using third degree polynomial expressions. The three coefficients describing the scanning curves is determined for each wetting and drying case by assuming a relation between the slope of boundary sorption curve and the scanning curve at the point where the moisture response enters the scanning domain. Furthermore, assuming that the slope of the scanning curve is the same as the boundary curve at the junction point, that is, at the point where the scanning curve hits the boundary curve once leaving the scanning domain, a complete cyclic behaviour can be considered. A finite element approach is described, which is capable of solving the nonlinear coupled equation system. The numerical calculation is based on a Taylor expansion of the residual of the stated problem together with the establishment of a NewtonRaphson equilibrium iteration scheme within the time steps. Examples are presented illustrating the performance and potential of the model. Two different types of measurements on moisture content profiles in concrete are used to verify the relevance of the novel proposed model for moisture transport and sorption. It is shown that a good match between experimental results and model predictions can be obtained by fitting the included material constants and parameters. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/1672566
 author
 Johannesson, B. and Nyman, Ulf ^{LU}
 organization
 publishing date
 2010
 type
 Contribution to journal
 publication status
 published
 subject
 keywords
 Diffusion, Moisture, Sorption hysteresis, Transport model, Sorption, Finite elements, Numerical methods
 in
 Transport in Porous Media
 volume
 84
 issue
 3
 pages
 735  754
 publisher
 Kluwer
 external identifiers

 wos:000281260000011
 scopus:77956011645
 ISSN
 01693913
 DOI
 10.1007/s1124201095383
 language
 English
 LU publication?
 yes
 id
 2805d4e64263439d95da6fee3831cb7c (old id 1672566)
 date added to LUP
 20160401 13:53:17
 date last changed
 20200115 04:19:51
@article{2805d4e64263439d95da6fee3831cb7c, abstract = {A numerical approach for moisture transport in porous materials like concrete is presented. The model considers mass balance equations for the vapour phase and the water phase in the material together with constitutive equations for the mass flows and for the exchange of mass between the two phases. Historydependent sorption behaviour is introduced by considering scanning curves between the bounding desorption and absorption curves. The method, therefore, makes it possible to calculate equilibrium water contents for arbitrary relative humidity variations at every material point considered. The scanning curves for different wetting and drying conditions are constructed by using third degree polynomial expressions. The three coefficients describing the scanning curves is determined for each wetting and drying case by assuming a relation between the slope of boundary sorption curve and the scanning curve at the point where the moisture response enters the scanning domain. Furthermore, assuming that the slope of the scanning curve is the same as the boundary curve at the junction point, that is, at the point where the scanning curve hits the boundary curve once leaving the scanning domain, a complete cyclic behaviour can be considered. A finite element approach is described, which is capable of solving the nonlinear coupled equation system. The numerical calculation is based on a Taylor expansion of the residual of the stated problem together with the establishment of a NewtonRaphson equilibrium iteration scheme within the time steps. Examples are presented illustrating the performance and potential of the model. Two different types of measurements on moisture content profiles in concrete are used to verify the relevance of the novel proposed model for moisture transport and sorption. It is shown that a good match between experimental results and model predictions can be obtained by fitting the included material constants and parameters.}, author = {Johannesson, B. and Nyman, Ulf}, issn = {01693913}, language = {eng}, number = {3}, pages = {735754}, publisher = {Kluwer}, series = {Transport in Porous Media}, title = {A Numerical Approach for NonLinear Moisture Flow in Porous Materials with Account to Sorption Hysteresis}, url = {http://dx.doi.org/10.1007/s1124201095383}, doi = {10.1007/s1124201095383}, volume = {84}, year = {2010}, }