• 한국해양공학회지
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• 제14권1호
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• pp.60-66
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• 2000

In order to study for corrosion behavior of reinforcing steel with oxidation layer. Experiments were done with various NaCl concentrations and with immersion time in simulated concrete pore solution(SPS) the characteristics of corrosion behavior were measured by polarization resistance method and cyclic potentiodynamic method. reinforcements were coated by epoxy except corrosion without oxidation layer and it also showed two anodic-nose. by the result of potention dynamic test the potential curve shift to low with time and anodic-nose was appeared with 3% NaCl solution after 15 days. By result of cyclic Potentiodynamic test the type of corrosion was different accoding to concentration.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.33-34
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• 2023

Corrosion of reinforcement steel is a major cause of deterioration in reinforced concrete (RC) structures. In order to protect these structures from corrosion, corrosion inhibitors are added to the concrete mix. In recent years, zwitterionic compounds have shown promising results as corrosion inhibitors in concrete due to their ability to form a protective layer on the surface of the reinforcement steel. The experimental study involves preparing concrete samples with different concentrations of adding the hybrid corrosion inhibitor at a high concentration of chloride ions. This study aims to determine the chloride threshold value and service life of hybrid corrosion inhibitors in reinforced concrete based on zwitterions. The samples are subjected to accelerated corrosion tests in a chloride environment to determine the threshold value and service life of the corrosion inhibitor. The effect of hybrid inhibitor on mechanical properties is guaranteed in allowable range. The chloride threshold concentration and service life of hybrid inhibitor containing samples perform greater than those of plain RC.

• Computers and Concrete
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• 제29권3호
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• pp.145-159
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• 2022

In this study, the extreme learning machine and deep learning models were devised to estimate the bond strength of corroded reinforcement in concrete. The six inputs and one output were used in this study. The compressive strength, concrete cover, bond length, steel type, diameter of steel bar, and corrosion level were selected as the input variables. The results of bond strength were used as the output variable. Moreover, the Analysis of variance (Anova) was used to find the effect of input variables on the bond strength of corroded reinforcement in concrete. The prediction results were compared to the experimental results and each other. The extreme learning machine and the deep learning models estimated the bond strength by 99.81% and 99.99% accuracy, respectively. This study found that the deep learning model can be estimated the bond strength of corroded reinforcement with higher accuracy than the extreme learning machine model. The Anova results found that the corrosion level was found to be the input variable that most affects the bond strength of corroded reinforcement in concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.537-542
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• 2001

Recently long-span bridges, such as Kwang-Ahn Grand bridge, Seo-Hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the shore. It needs to maintain the durability of marine concrete structures which are exposed to severe chloride environments. It is well known that corrosion of reinforcement steels in concrete structure is the most important cause for the durability of concrete structure which can be controlled by systematic preparatory corrosion protection works for economic and safe infrastructures. Various corrosion protection systems have been used for the corrosion protection of reinforcement steels from detrimental chemical components such as chloride, sulphate and etc. Since chloride can be penetrated into concrete in a variety way, an effective method has to be adopted by taking into full economical aspects and technical data of each protection system. The objective of this experimental study is to investigate the corrosion behavior of reinforcing steel in laboratory concrete specimens which are exposed to cyclic wet and dry saltwater, and then to develop pertinent corrosion protection system, such as corrosion inhibitors and cathodic protection for reinforced concrete bridges exposed to chloride environment. Resistance of various corrosion inhibitors and impressed current system have been experimentally evaluated under severe environmental conditions, and thus effective corrosion protection systems could have been Practically developed for future concrete construction.

• 공업화학
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• 제9권6호
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• pp.907-913
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• 1998

전기화학적 임피던스법(electrochemical impedance spectroscopy, EIS)을 사용하여 염소이온에 의한 철근 콘크리트의 부식현상을 연구하였다. 콘크리트를 만들 때 물에 용해된 상태의 염소이온은 콘크리트 내부에 존재하게 되며, 이 염소이온의 농도를 변화시키며 실험을 수행하였다. 재령 400일 이상 EIS법으로 측정한 결과, 세밀한 전기화학적 등가회로 및 물리적 모델을 구성하였으며, 얻어진 임피던스 파라미터로부터 철근 콘크리트의부식현상을 물리적 모델로 설명할 수 있었다. 실험에서 얻은 측정값과 CNLS(complex nonlinear least squares) fitting법으로 구한 값은 잘 일치하였으며, 모델로부터 얻어진 임피던스 상수를 이용하여 부식 속도를 계산할 수 있어 이를 통한 부식 속도 예측이 가능함을 알 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.265-271
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• 1997

Marine concrete structures have been exposed to salt from ocean environments. Chloride-penetration into marine concrete structures should accelerate the corrosion of reinforcement steel, which may severely affect the durability of them. Major concerns are to develop durable concrete for high corrosion resistance of reinforcing steel embedded in concrete. The objective of this experimental study is to investigate adequate usage of corrosion inhibitors by evaluating corrosion level in 80 specimen located in the labatory and in the site. 80 specimen of cube 20${\times}$20${\times}$11.5 and 63 specimen of slab 30${\times}$30${\times}$10 are made for this study.

• 한국해양공학회지
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• 제12권3호통권29호
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• pp.68-74
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• 1998

An increase of concrete construction in marine environments as well as an increasing use of marine aggregate at the mixing stage of concrete has provoked an important problem. A high concentration of chloride ion in the vicinity of steel bars in concrete is the principal cause of premature reinforcement corrosion in concrete structures. In this study, the behavior of chloride ions introduced into concrete from concrete surface by marine evironment was analysed. A mathematical model including the diffusion of chloride ion in aqueous phase of pores, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete and the chemical reactions of chloride ions with solid phase was presented. Finite element method was employed to carry out numerical analysis. The results of this study may be used to predict the onset of reinforcement corrosion and to identify the maximum limit of chloride ions contained in concrete admixtures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.487-490
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• 2005

In this study, for the establishment of the performance evaluation methods and the quality control standards of durability recovery method, the data of indoor durability test and the data of the long term exposure test under the coast are accumulated and analyzed. As a result of the indoor test, durability of repair material was more superior to that of plain concrete, but as a result of investigating and evaluating exposure test at 30 month of exposure age under the coastal environment, the difference in electric potential and the reinforcement corrosion at place replaced with repair material are found.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.257-262
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• 1997

Reinforced concrete structures built on the seashore or in seawater are damaged from saltwater which cause to accelerate corrosion of reinforcing steel in concrete. Therefore, Corrosion of steel reinforcement of concrete structures become more and more serious, and prediction of service lives of concrete structures considering steel corrosion is needed much more. this research is to investigate basic physical properties of various corrosion inhibitors and to evaluate their corrosion resistance in concrete. The object of this study is develop appropriate corrosion protection systems so as to enhance the durability of concrete.

• Computers and Concrete
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• 제2권4호
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• pp.325-343
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• 2005

Chloride ingress is a common cause of deterioration of reinforced concrete located in coastal zone. Modeling the chloride ingress is an important basis for designing reinforced concrete structures and for assessing the reliability of an existing structure. The modeling is also needed for predicting the deterioration of a reinforced structure. The existing deterministic solution for prediction model of corrosion initiation cannot reflect uncertainties which input variables have. This paper presents an approach to the fuzzy arithmetic based modeling of the chloride-induced corrosion of reinforcement in concrete structures that takes into account the uncertainties in the physical models of chloride penetration into concrete and corrosion of steel reinforcement, as well as the uncertainties in the governing parameters, including concrete diffusivity, concrete cover depth, surface chloride concentration and critical chloride level for corrosion initiation. There are a lot of prediction model for predicting the time of reinforcement corrosion of structures exposed to chloride-induced corrosion environment. In this work, RILEM model formula and Crank's solution of Fick's second law of diffusion is used. The parameters of the models are regarded as fuzzy numbers with proper membership function adapted to statistical data of the governing parameters instead of random variables of probabilistic modeling of Monte Carlo Simulation and the fuzziness of the time to corrosion initiation is determined by the fuzzy arithmetic of interval arithmetic and extension principle. An analysis is implemented by comparing deterministic calculation with fuzzy arithmetic for above two prediction models.