• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.553-558
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• 2012

Airborne chlorides are transported to inland by sea wind to be attached to seashore concrete structure surface then penetrated into concrete structure members. Since the surface attached chloride amount are dependent on the amount of airborne chlorides, the prediction of distribution of airborne chlorides is important information in preventing chloride corrosion problems in seashore concrete structures. The prediction of surface chloride amount from airborne chlorides environment is extremely difficult than concrete directly in contact with seawater. In addition, their penetrating tendency is different from that of concrete immersed in seawater. In this study, properties of surface and penetrated chlorides under airborne chlorides environment are investigated. Concrete specimens were manufactured and exposed to marine environment for 3 years. The specimens were analyzed at the time durations of 1, 2, and 3 years to check surface chloride amount to penetrated chloride depth. The results revealed that there were certain differences according to surface roughness of concrete and with and without washing effect due to rainfalls. The evaluation results showed that penetrated chlorides depend on amount of airborne chlorides and duration of exposure. In addition, a notable tendency of having deeper chloride penetration and higher chloride content in concrete members under long-term exposure was observed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.45-53
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• 2023

In this study, to analyze the correlation of surface chloride and corrosion amount level according to the installation location of steel members exposed to the marine environment, the surface chloride and mean corrosion depth were evaluated by member units for box girder members of the offshore steel bridge and box specimens. The surface chloride was measured monthly using the Bresle method for one year. The corrosion amount was evaluated by converting the weight loss due to corrosion products generated in the monitoring steel plate into mean corrosion depth. As a measurement result of the surface chloride and corrosion amount, relative differences in surface chloride and mean corrosion depth were appeared depending on the shape or installation location of the steel members. Moreover, even if members of the same shape were installed in the same bridge, it was confirmed that the corrosion amount was increased locally and rapidly. The tendency of corrosion amount depending on the surface chloride was evaluated to analyze the correlation between surface chloride and corrosion amount, and the relation equations that can asseses the corrosion amount depending on the surface chloride were analyzed. From the results of the correlation between surface chloride and corrosion amount, it was found that the corrosion amount of the steel member affected by the surface chloride was varied up to about 1.15 times depending on the structural detail.

• 한국해양학회지
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• v.19 no.2
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• pp.105-110
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• 1984

We study the annual variation of salinity at the sea surface and at 30m depth in the neighbouring seas of korea by the harmonic method. The analysis based on the monthly salinity data at 182 stations collected regularly by the Fisheries Research and Development Agency during 15 years (1961∼1975). The annual mean salinity in the West Sea is lower than that in the East Sea. In the amplitude of annual salinity variation decreases and the phase delays with the downstream distance of the Tsushima Current. The salinity at 30m has a higher mean, a smaller amplitude and a delayed phase than the corresponding ones at the surface. The annual variations of salinity in the South and East Seas are caused mainly by the annual variations of the local precipitation and that of the fresh water discharge from the Yangtze River.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.11-18
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• 2021

Nano bubble water is used in various washing processes, including cleaning of solar panels, salt rejection of roads, and cleaning precision parts of machines. High cleaning efficiency and water conservation are obtained by applying nano bubbles during pretreatment of the marine waste cleaning system. This study compared the salt rejection of nano bubble water, and it was revealed that marine waste was produced by wood immersed in 200,000 mg/L NaCl solution. Using tap water and nano bubble water for washing, comparisons of the surface salt concentrations of wood were determined according to the nozzle, orifice diameter, pump speed and washing time. Decreased surface salt concentration was observed on the wood surface with increasing washing time. Water consumption was optimal between 5- and 10-seconds washing time. Increasing orifice diameter of the nozzle reduced the spraying pressure, with consequent increase in the wood surface salt concentration, thereby establishing the importance of orifice diameter of the nozzle. Compared to levels obtained with tap water, salt concentration of the wood surface after washing with nano bubble water was 2.2% lower with sector nozzle, and 30.9% lower with circular nozzle. In the washing experiment using nano bubble water, the salt concentration on the wood surface was about 9.5 mg/L lower when washed with sector nozzle than the circular nozzle.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.116-118
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• 2011

해안가에 건설되는 구조물 표면은 해풍에 의해 직접적인 영향을 받는다. 해풍에 섞여 날아오는 염분이 건축물 외부에 흡착하여 시간이 경과함에 따라 내부로 확산 이동하게 되어, 콘크리트 내부의 철근이 부식하게 된다. 따라서, 해안가 구조물의 비래염분에 대한 열화 예측을 보다 정확하게 조사하기 위해서는 실환경하에 작용하는 기상요인, 지형, 구조물의 형태 등 대상지역의 다양한 조건을 정밀하게 반영하여 정해야 할 필요가 있다. 풍향, 풍속, 온도, 습도등의 다양하게 변화하는 기상요인에서 각 요인에 따라 발생되는 비래염분량과의 상관성을 분석하기 위해서는 고정된 실험인자에 따른 지속적인 실험이 필요하다. 따라서 본 연구는 비래염분 포집기 개발 및 인공비래염분 발생장치(이하, 인공장치) 개발과 장치 성능의 정확성 향상을 위한 기초 실험 실시에 목표를 하였고, 또한 개발된 비래염분 포집기를 실 환경에 설치하여 각 실험인자에 따른 실환경에서의 비래염분 포집량을 분석하고자 한다.

• Journal of the Korea Computer Industry Society
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• v.9 no.3
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• pp.137-142
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• 2008

The major influence factor on chloride penetration into concrete structures is chloride ion concentration. In this study, chloride penetration analyses with chloride ion concentration were carried out by the developed program. Also, the service life of concrete structures was predicted. The penetration depth was 32mm in case that chloride ion concentration wad 600ppm. It was shown that the service life of concrete structures with 40mm cover depth was 167 years even though they had been exposed at chloride ion concentration 600ppm during 100 years.

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.233-241
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• 1997

최근 해안환경하에 있는 콘크리트구조물의 철근부식은 구조물의 내구성 저하 및 유지관리라는 차원에서 커다란 문제점을 가지고 있다. 이와 같은 현상은 해양구조물의 건설이 날로 증가하고 있고, 또 콘크리트 제조시 잔골재의 일부를 염분이 함유된 해사를 사용함으로써 더욱 심각해지고 있다. 본 연구에서는 콘크리트 표면으로부터 침투해 들어오는 침입염분의 거동을 모델화하였으며, 콘크리트 세공속의 수용액상에 있은 염화물이온의 확산을 포함하는 물리 화학적 진행, 시멘트 수화물에 고정되는 염분의 흡착과 탈착 및 고정염과의 화학반응 등의 현상을 유한요소법에 의해 해석을 실시하였다. 본 연구의 결과는 콘크리트 내부의 철근 발청시기의 예측, 해안환경하에 있는 콘크리트 구조물의 침투 염분에 의한 콘크리트 덮개의 결정, 콘크리트 구조물의 염화물이온의 허용치 설정을 비롯하여 내구년수를 예측하는데 유용하게 활용될 수 있을 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.51-51
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• 2020

본 연구에서는 기수역에서의 GPS 전자부자를 활용한 계측 데이터와 염분측정 데이터를 비교분석하여 GPS 전자부자의 거동 특성이 담수의 실제 거동특성과 같이 일치하게 나타나는지 확인하고, GPS 전자부자에 대한 활용성을 증명하고자 하였다. 기수역에서의 담수와 해수의 분포를 확인하기 위해서는 많은 인력과 장비를 소모하며 수리량과 염분도에 대한 측정을 통해 분석을 할 수 있는데, 대표적인 수리량 측정장비인 ADCP 또는 ADV는 각종 측정 한계들이 존재한다. 따라서 이러한 기수역에서의 수체 구간별 흐름 특성이 어떻게 나타나는지 확인하기 위해서 GPS 전자부자를 활용하고자 하였으며. GPS 전자부자의 데이터와 수직방향으로 측정한 염분도 데이터와 비교하고자 하였다. 수영강 좌수영교 상류 1km지점에서 주입하였으며 간조 시와 만조 시에 유하시켜 수영강에 위치한 좌수영교와 수영교에서 각각 좌측, 중간, 우측에서 수심방향으로 측정한 염분도를 상층 중층 하층으로 평균하여 비교하였다. 본 연구에서 사용한 GPS 전자부자는 표면부자이기 때문에 만조 시 하류방향으로 더 뻗어 나가는것으로 확인하였고, 간조 시에는 흐름이 더디거나 정체하는 것으로 나타났다. 이러한 계측 결과는 담수의 흐름 특성과 일치하게 나타나는 것을 확인하였고 이러한 GPS Floater를 활용한다면 굳이 각종 수질을 측정하지 않아도 흐름 상황으로 간조인지 만조인지에 대한 상황과 염분 분포를 대략적으로 알 수 있다. 이러한 GPS 전자부자의 위치데이터와 시간을 잘 이용한다면 ADCP의 유속 측정에 대한 단점을 보완할 수 있는 Lagrangian 타입의 유속을 측정 할 수 있다. 이러한 GPS 전자부자를 하천에서 선주입으로 활용한다면 각 구간별로 수체에 대한 흐름과 유속들을 분석할 수 있을 것으로 사료된다. 또한 GPS 전자부자를 좀더 활용하여 IoT 기반 수질센서 등과 같은 각종 센서가 GPS Floater에 결합이 된다면, 흘러가면서 각종 데이터 정보취득을 통해 수체내 흐름을 분석하는 것뿐만 아니라 수환경 유출오염사고들에 대한 초기대응에 많은 도움이 될 것으로 사료 된다.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.667-673
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• 1998

Rebar corrosion in a simulated pore solution (SPS) with chloride ion was analyzed by Tafel and AC impedance method and corrosion effects of surface roughness and iron oxide layer were also investigated. Corrosion estimation of rebar by electrochemical impedance spectroscopy is very useful, and the measured value can be adapted to proposed electrochemical equivalent circuit model. Corrosion potential increased to the cathodic direction as the concentration of chloride ions increased and corrosion current had the same tendency as above. Surface films were analyzed with scanning electron microscope and Auger electron spectroscopy. Thermally oxidized layer by torch flame for 15 sec was very poor at anti-corrosive property. The corrosion rate of rebar increased as the surface roughness increased. Also, higher temperatures above RT of SPS in initial stage caused a rebar to be corroded faster.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.57-58
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• 2014

For durability design to protect against chloride-induced corrosion, it is important to estimate the amount of chlorides on the surface. However, it is difficult to estimate the airborne chlorides, a boundary condition, due to the difference between the amount of chlorides attached to a surface of an actual structure and that in the air. Therefore, in this study the attachment rate analysis of airborne chlorides was evaluated for 13 types of finish materials. As a result, despite differences in the amount of airborne chlorides according to the finishing type, it was found that 60 percent of airborne chlorides were attached to mortar, 30 percent were attached to steel, and 25 percent were attached to tiles compared with the amount of chlorides in the air.