Influences of Time, Temperature, and Humidity on Chloride Diffusivity: Mesoscopic Numerical Research
Publication: Journal of Materials in Civil Engineering
Volume 29, Issue 11
Abstract
Chloride-induced corrosion of reinforcing steel bars has a big impact on the performance of reinforced concrete (RC) structures subjected to saline environments, and it is essential to understand how chloride ions ingress in concrete. In this study, first, an experiment of chloride ingress in specimens under one-dimensional and two-dimensional diffusion was conducted in a climate chamber, and profiles of chloride concentration along the depth were obtained. Then, a mesoscopic model that considers environmental factors, i.e., temperature, relative humidity, and time of exposure, was developed to investigate chloride diffusivity in concrete. Concrete is treated as a three-phase composite: cement paste, aggregates, and interfacial transition zones (ITZs). It is assumed that chloride diffusivity can take place only in the cement paste and ITZ, whereas the aggregate is considered impermeable. Influence of ITZ thickness, i.e., 0, 50, and 80 μm, on chloride diffusivity in concrete is examined. Chloride concentrations, which are simulated with the mesoscopic model with consideration of environmental factors, are compared with previous test data. Finally, time to corrosion initiation of RC structures is predicted based on the developed mesoscopic model considering the distribution of aggregates, and the influence of environmental factors on the chloride concentration of the corrosion initiation point is investigated. It is found that ITZs have a significant effect on chloride diffusivity in concrete. However, different thicknesses of the ITZ, i.e., 50 and 80 μm, have a small impact on the chloride diffusivity in concrete; hence, an ITZ thickness 80 μm is recommended for efficiency. The simulation results with consideration of the environmental factors are in good agreement with the test data, and the corrosion initiation point on the surface of the steel embedded in concrete varies because of the distribution of aggregates. Corrosion initiation time decreases with increases in the water-to-cement (w/c) ratios but increases with increases in the thickness of cover, temperature, and humidity. An increase in either temperature or relative humidity can lead to a significant increase in the chloride concentration of the corrosion initiation point on the steel.
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Acknowledgments
The financial support of National Basic Research Program of China (973 Program, Grant No. 2015CB057701), National Natural Science Foundation of China (Grant No. 51378081), Hunan Provincial Postgraduate Innovation Project (Grant No. CX2015B344), and Excellent Young Research Program by Department of Education at Hunan Province (15B015), and China Scholarship Council (File No. 201603780063) are gratefully acknowledged.
References
Costa, A., and Appleton, J. (1999). “Chloride penetration into concrete in marine environment. II: Prediction of long term chloride penetration.” Mater. Struct., 32(5), 354–359.
Darmawan, M. S., and Stewart, M. G. (2007). “Spatial time-dependent reliability analysis of corroding pretensioned prestressed concrete bridge girders.” Struct. Saf., 29(1), 16–31.
Dehghanpoor Abyaneh, S., Wong, H. S., and Buenfeld, N. R. (2013). “Modelling the diffusivity of mortar and concrete using a three-dimensional mesostructure with several aggregate shapes.” Comp. Mater. Sci., 78, 63–73.
Delagrave, A., Bigas, J. P., Ollivier, J. P., Marchand, J., and Pigeon, M. (1997). “Influence of the interfacial zone on the chloride diffusivity of mortars.” Adv. Cem. Based Mater., 5(3–4), 86–92.
Du, X., Jin, L., and Ma, G. (2014). “A meso-scale numerical method for the simulation of chloride diffusivity in concrete.” Finite Elem. Anal. Des., 85, 87–100.
Duprat, F. (2007). “Reliability of RC beams under chloride-ingress.” Constr. Build. Mater., 21(8), 1605–1616.
El Hassan, J., Bressolette, P., Chateauneuf, A., and El Tawil, K. (2010). “Reliability-based assessment of the effect of climatic conditions on the corrosion of RC structures subject to chloride ingress.” Eng. Struct., 32(10), 3279–3287.
Garboczi, E., and Bentz, D. (1996). “The effect of the interfacial transition zone on concrete properties: The dilute limit.” Mater. New Millennium, 2, 1228–1237.
Khanzadeh Moradllo, M., Shekarchi, M., and Hoseini, M. (2012). “Time-dependent performance of concrete surface coatings in tidal zone of marine environment.” Constr. Build. Mater., 30, 198–205.
Li, C. Q., and Melchers, R. E. (2005). “Time-dependent risk assessment of structural deterioration caused by reinforcement corrosion.” ACI Struct. J., 102(5), 754–762.
Li, L. Y., Xia, J., and Lin, S. S. (2012). “A multi-phase model for predicting the effective diffusion coefficient of chlorides in concrete.” Constr. Build. Mater., 26(1), 295–301.
Liu, Q. F., Xia, J., Easterbrook, D., Yang, J., and Li, L. Y. (2014). “Three-phase modelling of electrochemical chloride removal from corroded steel-reinforced concrete.” Constr. Build. Mater., 70, 410–427.
McGee, R. (1999). “Modelling of durability performance of Tasmanian bridges.” Proc., ICASP 8: Applications of Statistics and Probability, R. E. Melchers and M. G. Stewart, eds., Taylor & Francis, London, 297–306.
Melchers, R. E., Li, C. Q., and Lawanwisut, W. (2008). “Probabilistic modeling of structural deterioration of reinforced concrete beams under saline environment corrosion.” Struct. Saf., 30(5), 447–460.
Oh, B. H., and Jang, S. Y. (2004). “Prediction of diffusivity of concrete based on simple analytic equations.” Cem. Concr. Res., 34(3), 463–480.
Pack, S. W., Jung, M. S., Song, H. W., Kim, S. H., and Ann, K. Y. (2010). “Prediction of time dependent chloride transport in concrete structures exposed to a marine environment.” Cem. Concr. Res., 40(2), 302–312.
Page, C. L., Short, N. R., and Tarras, A. E. (1981). “Diffusion of chloride ions in hardened cement pastes.” Cem. Concr. Res., 11(3), 395–406.
Pan, Z., Chen, A., and Ruan, X. (2015). “Spatial variability of chloride and its influence on thickness of concrete cover: A two-dimensional mesoscopic numerical research.” Eng. Struct., 95, 154–169.
Stewart, M. G., and Mullard, J. A. (2007). “Spatial time-dependent reliability analysis of corrosion damage and the timing of first repair for RC structures.” Eng. Struct., 29(7), 1457–1464.
Sun, G., Zhang, Y., Sun, W., Liu, Z., and Wang, C. (2011). “Multi-scale prediction of the effective chloride diffusion coefficient of concrete.” Constr. Build. Mater., 25(10), 3820–3831.
Val, D. V., and Trapper, P. A. (2008). “Probabilistic evaluation of initiation time of chloride-induced corrosion.” Reliability Eng. Syst. Saf., 93(3), 364–372.
Walranen, J. C., and Reinhardt, H. W. (1981). “Theory and experiments on the mechanical behaviour of cracks in plain and reinforced concrete subjected to shear loading.” HERON, 26(1A), 26–35.
Wang, L. C., and Ueda, T. (2009). “Meso-scale modeling of chloride diffusion in concrete with consideration of effects of time and temperature.” Water Sci. Eng., 2(3), 58–70.
Zheng, J., and Zhou, X. (2008). “Analytical solution for the chloride diffusivity of hardened cement paste.” J. Mater. Civ. Eng., 384–391.
Zheng, J. J., Zhou, X. Z., Wu, Y. F., and Jin, X. Y. (2012). “A numerical method for the chloride diffusivity in concrete with aggregate shape effect.” Constr. Build. Mater., 31, 151–156.
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Published In
Journal of Materials in Civil Engineering
Volume 29 • Issue 11 • November 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Aug 4, 2016
Accepted: May 23, 2017
Published online: Sep 11, 2017
Published in print: Nov 1, 2017
Discussion open until: Feb 11, 2018
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