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Computers and Concrete Volume 7, Number 5, October 2010 , pages 421-435 DOI: https://doi.org/10.12989/cac.2010.7.5.421 |
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Modeling of ion diffusion coefficient in saturated concrete |
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Xiao-Bao Zuo, Wei Sun, Cheng Yu and Xu-Rong Wan
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| Abstract | ||
| This paper utilizes the modified Davis model and the mode coupling theory, as parts of the electrolyte solution theory, to investigate the diffusivity of the ion in concrete. Firstly, a computational model of the ion diffusion coefficient, which is associated with ion species, pore solution concentration, concrete mix parameters including water-cement ratio and cement volume fraction, and microstructure parameters such as the porosity and tortuosity, is proposed in the saturated concrete. Secondly, the experiments, on which the chloride diffusion coefficient is measured by the rapid chloride penetration test, have been carried out to investigate the validity of the proposed model. The results indicate that the chloride diffusion coefficient obtained by the proposed model is in agreement with the experimental result. Finally, numerical simulation has been completed to investigate the effects of the porosity, tortuosity, water-cement ratio, cement volume fraction and ion concentration in the pore solution on the ion diffusion coefficients. The results show that the ion diffusion coefficient in concrete increases with the porosity, water-cement ratio and cement volume fraction, while we see a decrease with the increasing of tortuosity. Meanwhile, the ion concentration produces more obvious effects on the diffusivity itself, but has almost no effects on the other ions. | ||
| Key Words | ||
| diffusion coefficient; concrete; ion; model; electrolyte solution theory. | ||
| Address | ||
| Xiao-Bao Zuo: Jiangsu Key Laboratory of Construction Materials, Southeast University, Nanjing 211189, P.R. China Department of Civil Engineering, Nanjing University Of Science & Technology, Nanjing 210094, P.R. China Wei Sun and Cheng Yu: Jiangsu Key Laboratory of Construction Materials, Southeast University, Nanjing 211189, P.R. China Xu-Rong Wan: Department of Civil Engineering, Nanjing University Of Science & Technology, Nanjing 210094, P.R. China | ||