Transport in Porous Media

, Volume 98, Issue 1, pp 125–146 | Cite as

Effect of Moisture Movement on Tested Thermal Conductivity of Moist Aerated Autoclaved Concrete

  • M. Campanale
  • M. DeganelloEmail author
  • L. Moro


The purpose of this work was to study both theoretically and experimentally the process of moisture redistribution and heat transfer due to phase changes during the tests of thermal conductivity in aerated autoclaved concrete (AAC) moist specimens. The different moisture contents of the test samples were obtained in climatic chamber at equilibrium conditions reached with constant air temperature and variable relative humidity. The moist specimens were sealed inside highly impermeable polyethylene bag, as required by UNI 10051, and placed in a heat flow meter apparatus. During the experimental thermal conductivity measurements, the temperature and heat flow rate were measured under transient and steady state conditions. A theoretical analysis of the heat and mass transfer process was performed and then a suitable numerical model was used to predict the moisture redistribution and heat transfer due to the phase changes. The theoretical model has been compared against the experimental data. Substantial agreement between numerical results and experimental data was found. Then several numerical simulations have been performed to study the influence of the errors due to phase changes and non-uniform moisture distribution during the test of thermal conductivity of moist AAC specimens.


Thermal conductivity Moisture redistribution Phase changes  Porous medium 

List of Symbols









Specific heat (J/kg K)


Diffusion coefficient (m\(^{2}\)/s)




Specific enthalpy (J/kg)


Gravity vector (m/s\(^{2}\))


Mass flux vector (kg/m\(^{2}\,\)s)


Intrinsic permeability (m\(^{2}\))


Thickness (m)


Molar mass (kg/kmol)


Mass (kg)


Evaporated water in units of time and volume (kg/m\(^{3}\,\)s)




Pressure (Pa)


Heat flux vector (W/m\(^{2}\))


Universal gas constant (J/kmol K)


Pore radius (m)


Relative humidity




Temperature (K)


Time (s)


Moisture content mass by mass


Velocity vector (m/s)


Moisture content mass by volume (kg/m\(^{3}\))

Greek Symbols

\(\alpha \)


\(\beta \)


\(\delta \)


\(\varepsilon \)


\(\gamma \)

Surface tension (N/m)

\(\lambda \)

Thermal conductivity (W/m K)

\(\mu \)

Viscosity (kg/m s)

\(\rho \)

Density (kg/m\(^{3}\))

\(\tau \)










Dry air


Gaseous phase




Liquid phase










Water vapor


  1. Baggio, P., Maiorana, C.E., Schrefler, B.A.: Thermo-hygro-mechanical analysis of concrete. Int. J. Numer. Methods Fluids 20, 573–595 (1995)CrossRefGoogle Scholar
  2. Baggio, P., Campanale, M., Moro, L.: Analytical and experimental investigations on the transient heat transfer process in moist wood wool slabs. J. Therm. Envel. Build. Sci. 24, 211–225 (2001)CrossRefGoogle Scholar
  3. Degiovanni, A., Moyne, C.: Conductivité thermique de matériaux poreux humides: évaluation théorique et possibilité de mesure. Int. J. Heat Mass Transf. 30(11), 2225–2245 (1987)CrossRefGoogle Scholar
  4. Galbraith, G.H., Mclean, R.C., Guo, J., Kelly, D., Lee, C.: The use of differential permeability in moisture transport modelling. In: Proceedings of Building Performance Simulation, Kyoto, vol. 1, pp. 267–271 (1999)Google Scholar
  5. Hansen, K.K.: Sorption Isotherms, a Catalogue. Department of Civil Engineering, The Technical University of Denmark, Building Materials Laboratory (1986)Google Scholar
  6. Hassanizadeh, M., Gray, W.G.: General conservation equations for multiphase systems: 1 averaging technique. Adv. Water Res. 2, 131–144 (1979)CrossRefGoogle Scholar
  7. Hassanizadeh, M., Gray, W.G.: General conservation equations for multiphase systems: 2 mass, momenta, energy and entropy equations. Adv. Water Res. 2, 191–203 (1979)CrossRefGoogle Scholar
  8. Hassanizadeh, M., Gray, W.G.: General conservation equations for multiphase systems: 3 constitutive theory for porous media flow. Adv. Water Res. 3, 25–40 (1980)CrossRefGoogle Scholar
  9. ISO 10051: Thermal insulation. Moisture effects on heat transfer. Determination of thermal transmissivity of a moist material (1996)Google Scholar
  10. Kumaran, M.K.: Moisture transport trough glass-fibre insulation in the presence of a thermal gradient. J. Therm. Insulation 10, 243–255 (1987)Google Scholar
  11. Nasrallah, S.B., Perre, P.: Detailed study of a model of heat and mass transfer during convective drying processes. Int. J. Heat Mass Transf. 31(5), 957–967 (1988)CrossRefGoogle Scholar
  12. Roels, S., Carmeliet, J., Hens, H., Adan, O., Brocken, H., Cerny, R., Pavlik, Z., Hall, C., Kumaran, K., Pel, L., Plagge, R.: Interlaboratory comparison of hygric properties of porous building materials. J. Therm. Envelope Build. Sci. 27(4), 307–325 (2004)Google Scholar
  13. Sandberg, P.I.: Thermal Resistance of Wet Insulation Materials. Technical Report 29. Swedish National Testing Institute, Boras, Sweden (1986)Google Scholar
  14. Whitaker, S.: Simultaneous heat mass and momentum transfer in porous media: a theory of drying. Adv. Heat Transf. 13, 119–203 (1977)CrossRefGoogle Scholar
  15. Whitaker, S.: Heat and mass transfer in granular porous media. Adv. Dry. 1, 23–61 (1980)Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.Department of Industrial EngineeringUniversity of PaduaPaduaItaly

Personalised recommendations