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Title |
Variations of Apparent Chloride Diffusion Coefficient in Long-term Soaked GGBFS Concrete Considering Three Levels of Exposure Environments
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Authors |
윤용식(Yong-Sik Yoon) ; 임희섭(Hee-Seob Lim) ; 권성준(Seung-Jun Kwon) |
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DOI |
https://doi.org/10.4334/JKCI.2019.31.5.467 |
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Keywords |
염해; 옥외 노출; 겉보기 염화물 확산계수; 고로슬래그 미분말; 압축강도 chloride attack; outdoor exposure; apparent chloride diffusion coefficient; GGBFS; compressive strength |
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Abstract |
Concrete structures in marine environments are degraded not only when they are immersed in sea water, but also by chloride ions from tidal and splash areas. It is well known that GGBFS (Ground Granulated Blast Furnace Slag) improves the pore structure in concrete through latent hydraulic activity and chloride resistance by considerable absorption of free chlorine ions. In this paper, marine environment exposure tests are performed considering three levels of water to binder ratio (W/B) and two levels of GGBFS replacement ratio. Three cases of exposure conditions (immersion zone, tidal zone, and splash zone) and three levels of exposure period (180 days, 365 days, and 730 days) are considered. In all cases, the lower the concrete W/B is and the higher the substitution ratio of GGBFS is, the lower the apparent chloride diffusion coefficient is. Also, at 730 days of exposure, the diffusion coefficient in GGBFS concrete decreases to 16 % of that in OPC concrete. Considering the effects of exposure conditions, high apparent chloride diffusion coefficient is evaluated in order of tidal zone, immersion zone, and splash zone for GGBFS concrete.
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