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Title |
Influence of Temperature on Chloride Ion Diffusion of Concrete
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Authors |
소형석 ; 최승훈 ; 서중석 ; 서기석 ; 소승영 |
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DOI |
https://doi.org/10.4334/JKCI.2014.26.1.071 |
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Keywords |
콘크리트 캐스크 ; 염해 ; 온도 ; 염화물이온 확산계수 ; 활성화 에너지 concrete cask ; salt attack ; high temperature ; chloride ion diffusion ; activation energy |
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Abstract |
The long term integrity of concrete cask is very important for spent nuclear fuel dry storage system. However, there are serious concerns about early deterioration of concrete cask from creaking and corrosion of reinforcing steel by chloride ion because the cask is usually located in seaside, expecially by combined deterioration such as chloride ion and heat, carbonation. This study is to investigate the relation between temperature and chloride ion diffusion of concrete. Immersion tests using 3.5% NaCl solution that were controlled in four level of temperature, i.e. 20, 40, 65, and 90℃, were conducted for four months. The chloride ion diffusion coefficient of concrete was predicted based on the results of profiles of Cl- ion concentration with the depth direction of concrete specimens using the method of potentiometric titration by AgNO3. Test results indicate that the diffusion coefficient of chloride ion increases remarkably with increasing temperature, and there was a linear relation between the natural logarithm values of the diffusion coefficients and the reciprocal of the temperature from the Arrhenius plots. Activation energy of concrete in this study was about 46.6 (W/C = 40%), 41.7 (W/C = 50%), 30.7 (W/C = 60%) kJ/mol under a temperature of up to 90℃, and concrete with lower water-cement ratio has a tendency towards having higher temperature dependency.
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