Computers and Concrete

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Modeling of sulfate ionic diffusion in porous cement based composites: effect of capillary size change

  • Gospodinov, Peter N. (Institute of Mechanics, Bulgarian Academy of Sciences)
  • Received : 2006.10.26
  • Accepted : 2007.02.05
  • Published : 2007.04.25
⟨ Previous Next ⟩

Abstract

The paper considers a theoretical model to study sulfate ion diffusion in saturated porous media - cement based mineral composites, accounting for simultaneous effects, such as filling micro-capillaries (pores) with ions and chemical products and liquid push out of them. Pore volume change and its effect on the distribution of ion concentration within the specimen are investigated. Relations for the distribution of the capillary relative radius and volume within the composite under consideration are found. The numerical algorithm used is further completed to consider capillary size change and the effects accompanying sulfate ion diffusion. Ion distribution within the cross section and volume of specimens fabricated from mineral composites is numerically studied, accounting for the change of material capillary size and volume. Characteristic cases of 2D and 3D diffusion are analyzed. The results found can be used to both assess the sulfate corrosion in saturated systems and predict changes occurring in the pore structure of the composite as a result of sulfate ion diffusion.

Keywords

Acknowledgement

Supported by : Bulgarian Ministry of Education and Sciences

References

  1. Garboczi, E. and Bentz, D. (1992), "Computer simulation of the diffusivity of cement-based materials", J. Mater. Sci., 27, 2083-2092. https://doi.org/10.1007/BF01117921
  2. Gospodinov, P. (2005), "Numerical simulation of 3D sulfate ion diffusion and liquid push out of the material capillaries in cement composites", Cement Concrete Res., 35(3), 520-526. https://doi.org/10.1016/j.cemconres.2004.07.005
  3. Gospodinov, P., Kazandjiev, R., Partalin, T. and Mironova, M. (1999), "Diffusion of sulfate ions into cement stone regarding simultaneous chemical reactions and resulting effects", Cement Concrete Res., 29(10), 1591-1596. https://doi.org/10.1016/S0008-8846(99)00138-6
  4. Marchand, J., Samson, E. and Maltais, Y. (1999), "Modeling microstructural alterations of concrete subjected to external sulfate attack", Material Science of Concrete - Special Volume: Sulfat Attack Mechanisms, American Ceram. Society (USA), 211-257.
  5. Marchand, J., Samson, E. and Maltais, Y. (2001), "Modeling ionic diffusion mechanisms in saturated cementbased materials - an overview", Material Science of Concrete - Ion and Mass Transport in Cement-Based Materials, American Ceram. Society (USA), D. Hooton et al. eds., 97-111.
  6. Matros, Yu. Sh. (1988) Non-steady Processes in Catalytic Reactors, Nauka, Novosibirsk,
  7. Mironova, M., Gospodinov, P. and Kazandjiev, R. (2002), "The effect of liquid push out of the material capillaries under sulfate ion diffusion in cement composites", Cement Concrete Res., 32(1), 9-15. https://doi.org/10.1016/S0008-8846(01)00621-4
  8. Samson, E., Marchand, J. and Beaudoin, J. J. (1999b), "Describing ion diffusion mechanisms in cement-based materials using the homogenization technique", Cement Concrete Res., 29(10), 1341-1345. https://doi.org/10.1016/S0008-8846(99)00101-5
  9. Samson, E., Marchand, J. and Beaudoin, J. J. (2000), "Modeling the influence of chemical reactions on the mechanisms of ionic transport in porous materials. An overview", Cement Concrete Res., 30(12), 1895-1902. https://doi.org/10.1016/S0008-8846(00)00458-0
  10. Samson, E., Marchand, J., Robert, J.-L. and Bournazel, J.-P. (1999a), "Modelling ion diffusion mechanisms in porous media", Int. J. Numer. Mech. Eng., 46, 2043-2060. https://doi.org/10.1002/(SICI)1097-0207(19991230)46:12<2043::AID-NME795>3.0.CO;2-7