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Title |
Evaluation of Chloride Absorption in GGBS Concrete by Impedance Measurements
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Authors |
김재환(Jaehwan Kim) ; 조한민(Han-Min Cho) ; 유영준(Young-Jun You) |
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DOI |
https://doi.org/10.11112/jksmi.2022.26.6.230 |
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Keywords |
콘크리트; 염화물; 흡수; 임피던스; 고로슬래그 Concrete; Chloride; Absorption; Impedance; GGBS |
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Abstract |
It is essential that service life of reinforced concrete structures in economic and safety aspects should be secured. It is well-known that chlorideattack is a typical deterioration mechanism in field concrete structures. To prevent serious accidents like collapse, many studies have been conductedto increase resistance of chloride ingress using concrete mixed with GGBS. The usage of GGBS concrete is nowadays mandatory. Since most concretesin the field are unsaturated, study regarding chloride absorption is necessary, but many studies have focused on the chloride diffusion phenomenon. Methods for evaluating chloride absorption are cost and improper in the field. It is necessary to develop a simple method for evaluating chloride absorptionin practice. This study evaluated resistance of chloride ingress in GGBS concretes with impedance measurement and absorption test. From the results,it was confirmed that the contents of absorbed chloride were linearly correlated with the measured electrical resistivities (or conductivities) in the concrete. At the end of the test, the electrical conductivities were 250.8 S/m (w/b=0.4) and 303.1 S/m (w/b=0.6) for PC concretes, and 2.6 S/m (w/b=0.4)and 64.4 S/m (w/b=0.6) for GGBS concretes, respectively. Considering influencing factors for chloride absorption and impedance measurement,chloride ingress into concrete is mainly affected by pore structures due to replacement of GGBS. Especially, formations of pore structure are differentwith binder, thereby binders should be considered in building reinforced concrete structures exposed to chloride environments.
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