Chloride Penetration in Nonsaturated Concrete
Publication: Journal of Materials in Civil Engineering
Volume 15, Issue 2
Abstract
The two governing equations that describe the diffusion of chloride ions into nonsaturated concrete are established. Material models for the four material parameters involved in the governing equations are developed, including chloride binding capacity, chloride diffusion coefficient, moisture capacity, and moisture diffusion coefficient. The planned attempt is to establish material models based on analytical results first, and if this is not possible, to develop empirical models based on dominant physical or chemical mechanism(s) at different scale levels and calibrate the individual model by related test data. The alternating-direction implicit (ADI) finite-difference method was employed for solving coupled two-dimensional moisture diffusion and chloride penetration equations. The numerical solutions are compared with the experimental results obtained by the 90-day ponding test (AASHTO T259-80). The numerical prediction agrees very well with the test data. Free chloride concentration profiles at different depths and different ages of concrete slab are presented. Two limiting cases for different initial relative humidity levels are analyzed in detail to study the dependence of the chloride diffusion on the moisture diffusion in nonsaturated concrete.
Get full access to this article
View all available purchase options and get full access to this article.
References
Ababneh, A., and Xi, Y. (2003a). “The coupling effect of drying shrinkage and moisture diffusion in concrete.” J. Eng. Mech., in press.
Ababneh, A., and Xi, Y. (2003b). “Experimental study on the effect of moisture diffusion on chloride penetration in concrete.” in press.
Ababneh, A., Xi, Y., and Willam, K. (2001). “Multiscale modeling of the coupled moisture diffusion and drying shrinkage of concrete.” Proc., 6th Int. Conf. on Creep, Shrinkage, and Durability Mechanics of Concrete and Other Quasi-Brittle Materials, MIT, Cambridge, Mass.
Andrade, C., and Whiting, D.(1996). “A comparison of chloride ion diffusion coefficients derived from concentration gradients and non-steady state accelerated ionic migration.” Mater. Struct., 29, 476–484.
Bazant, Z. P., and Najjar, L. J. (1972). “Nonlinear water diffusion of nonsaturated concrete.” Matériaux et Constructions, 5(25).
Carnahan, B., Luther, H. A., and Wilkes, J. O. (1969). Applied numerical methods, Wiley, New York.
Christensen, R. M. (1979). Mechanics of composite materials, Wiley, New York.
Costa, A., and Appleton, J.(1999). “Chloride penetration into concrete in marine environment. II: Prediction of long term chloride penetration.” Mater. Struct., 32, 354–359.
Jennings, H. M., and Tennis, P. D.(1994). “A model for the developing microstructure in portland cement paste.” Journal of Am. Ceram. Soc.,77(2), 3161–3172.
Martys, N. S., Torquato, S., and Bentz, D. P.(1994). “Universal scaling of fluid permeability for sphere packing.” Phys. Rev. E, 50(1), 403–408.
Page, C. L., Short, N. R., and El Tarras, A.(1981). “Diffusion of chloride ions in hardened cement paste.” Cem. Concr. Res., 11(3), 395–406.
Saetta, A. V., Scotta, R. V., and Vitaliani, R. V.(1993). “Analysis of chloride diffusion into partially saturated concrete.” ACI Mater. J., 90(5), 441–451.
Tang, L., and Nilson, L. O.(1993). “Chloride binding capacity and binding isotherms of OPC pastes and mortars.” Cem. Concr. Res., 23, 247–253.
Xi, Y.(1995a). “A model for moisture capacities of composite materials. I: Formulation.” Comput. Mater. Sci., 4, 65–77.
Xi, Y.(1995b). “A model for moisture capacities of composite materials. II: Application to concrete.” Comput. Mater. Sci., 4, 78–92.
Xi, Y., and Bazant, Z. P.(1999). “Modeling chloride penetration in saturated concrete.” J. Mater. Civ. Eng., 11(1), 58–65.
Xi, Y., Bazant, Z. P., Molina, L., and Jennings, H. M.(1994a). “Moisture diffusion in cementitious materials: Adsorption isotherm.” Adv. Cem. Based Mater., 1, 248–257.
Xi, Y., Bazant, Z. P., Molina, L., and Jennings, H. M.(1994b). “Moisture diffusion in cementitious materials: Moisture capacity and diffusivity.” Adv. Cem. Based Mater., 1, 258–266.
Xi, Y., and Jennings, H. M.(1997). “Shrinkage of cement paste and concrete modeled by a multiscale effective homogeneous theory.” Mater. Struct., 30, 329–339.
Xi, Y., Willam, K., and Frangopol, D. M.(2000). “Multiscale modeling of interactive diffusion processes in concrete.” J. Eng. Mech., 126(3), 258–265.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 15 • Issue 2 • April 2003
Pages: 183 - 191
Copyright
Copyright © 2003 American Society of Civil Engineers.
History
Received: May 31, 2001
Accepted: Apr 8, 2002
Published online: Mar 14, 2003
Published in print: Apr 2003
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.