• 한국수자원학회논문집
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• 제56권11호
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• pp.697-703
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• 2023

본 연구에서는 부식에 의한 관두께 감소를 예측하여 수정 간접평가법을 개발하였다. 수정 평가법과 직접평가법과 비교를 통해 노후상수관을 선정함에 있어 정확도를 확인하였다. 가중치 조정은 기존 평가항목의 중요도에 따라 수질부식성, 토양부식성, 매설깊이, 도로형태의 가중치를 낮추고 관두께의 가중치를 추가하는 방법으로 가중치를 산정하였고 그 결과 관두께의 가중치는 0.1530으로 결정하였다. 직접평가법과 비교한 결과 기존 간접평가법에 비해 수정 간접평가법의 정확도가 31.03% 상승한 것으로 분석되었다. 수정 간접평가법을 통해 노후 상수관의 개량 우선순위 선정 시 기존 간접평가법보다 정확하고 효율적으로 노후관을 선정할 수 있을 것이다.

• 한국안전학회지
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• 제21권2호
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• pp.1-6
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• 2006

It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damage caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of the pipeline structure. In this study, we estimate the allowable damage by comparing the ASTM B31G code to a modified theory considering diverse detailed corrosive forms. The ASTM B31 G code has been developed as the evaluation method for reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials. Furthermore, we suggest a method for estimating the expected life span of used pipelines by utilizing the reliability method based on major variables such as the depth and length of damage and the corrosion rate affecting the life expectancy of the pipelines.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.155-158
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• 2008

In this study we compared corrosion resistance tests which were carried out according to the national technique standard and the UL standard to ensure the reliability of smoke detectors in foul weather. The sensitivity of smoke detectors became so blunt that the least operational smoke concentration was a maximum change of 13% in the national technique standard, while it was a maximum change of 145% in the UL standard. As a result of this study the test method of corrosion resistance was made an objective evaluation in the national technique standard. Therefore it could be said that a basis of developing the test method of corrosion resistance was prepared for our country.

• 한국가스학회지
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• 제5권3호
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• pp.45-50
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• 2001

개방형 기화기는 해수를 이용하여 열교환을 수행함으로써 액체상태의 액화천연가스를 천연가스로 기화시키는 역할을 한다 86년부터 가동된 U-tyre 기화기는 천연가스생산과 관련된 중요설비 중 하나로서, 기화기 튜브는 항상 해수내에서 운전되고 있으며 기화기 튜브와 파이프사이의 용접부에서 해수로 인한 부식이 진행되고 있다. 본 연구에서는 용접부에서의 국부적인 부식원인을 찾기 위해 이종금속부식의 가능성을 평가해 보았으며 또한 비파괴적인 방법을 이용하여 부식피트의 깊이를 측정하고 유한요소를 통한 안전성 평가에 목적을 두었다. 이종금속부식가능성에 대하여 용접부 각 부위별로 시료를 채취하여 3.5$\%$(wt.) NaCl 용액내에서 모재와 용접부위의 부식전위를 측정하였으며, 비파괴 검사를 통한 잔류두께측정은 tangential radio-graphy 시험이 가장 신뢰성 있는 기법임이 확인되었다. 미세한 부식피트가 발생된 경우에는 표면형상 복제기법을 적용하였다. 비파괴적인 방법을 이용하여 산출된 부식피트의 깊이와 형상을 근거로 2차원 유한요소 해석을 수행함으로써 내압으로 인한 기화기 튜브의 안전성을 평가할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.793-796
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• 2004

In domestic, various repair materials and method systems to keep up with these reinforced concrete deteriorated due to salt damage, carbonation. chemical decay et. being developed and applied. However, present polymer cement mortar applied to section restoration system cause the problem of long-term working and economica] efficiency. because that is divided into two process of liquid corrosion prevention agent and polymer cement mortar. In this background, accelerated test with due regard to $3\%$ NaCl soaking and autoclave cure was performed to confirm steel bar corrosion prevention properties of polymer cement mortar mixed with corrosion prevention agent of powdered type. In conclusion. we confirmed application possibility and excellency of steel bar corrosion prevention properties of polymer cement mortar mixed with corrosion prevention agent of powdered type comparing general polymer cement mortar applied to section restoration system of present study.

• Corrosion Science and Technology
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• 제5권1호
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• pp.33-38
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• 2006

Current coating practice requires the thickness of anti-corrosion organic coatings to be over $250{\mu}m$ for immersion parts of ships and offshore structures and the corrosion resistance of these coatings has been evaluated by destructive and qualitative analysis. Recently, Electrochemical Impedance Spectroscopy(EIS) method has been employed, as an alternative, to evaluate corrosion resistance of organic coatings. This method is characterized as being nondestructive, reproducible, and quantitative in evaluating aging of organic coatings. In this study, EIS method was adopted to quantitatively and effectively select the coating systems having optimized protective performance. Evaluations of several epoxy and epoxy/polyurethane coating systems typically used for ships and offshore structures were carried out in wet($50^{\circ}C$, $90^{\circ}C$) and dry(room temp.) environments to accelerate the degradation of the organic coatings. These results were compared with the conventional scribed(scratched) test results. The plausible prediction model for determining the remaining life-time of coating systems was also proposed based on variations of impedance data, FT-IR and $T_g$ measurements results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.544-547
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• 2003

The owner of water pipeline has a burden of responsibility for the protection of corrosion and the prevention against leakage of water. So, they have been installed a CP(Cathodic Protection) System in odor to protect corrosion. And they also have been measured and analyzed the data about P/S(Pipe to Soil) potential of water pipeline. The P/S potential is basic data of evaluation for water pipeline corrosion. They need remote automatic corrosion monitoring system for easy maintenance. In this paper, The communication method was studied mainly. And the specifications of proposed TRS (Truncked Radio System ) terminal for corrosion monitoring are introduced briefly.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.3-4
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• 2014

There is high probability of steel corrosion on the reinforced concrete exposed to marine environment by penetration of chloride ion. When making concrete structure with slag as admixture in marine environment, salt damage can be prevented. Therefore, this paper presents experimental results of steel corrosion resistance of slag concrete considering marine environment through half-cell potential method which is one of the nondestructive test. As a result of half-cell potential experiment, it was assumed that every specimen exposed to marine environment was not corroded, and as a result of destroying specimens, it was confirmed that there was no corrosion in specimens.

• 한국해양공학회지
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• 제4권1호
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• pp.88-100
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• 1990

Among the test methods to evaluate stress-corrosion cracking(SCC) on the basis of fracture mechanics, constant displacement(bolt) loading method using modified-WOL specimen is practically convenient. In this test method, compliance formula is generally required to calculate load(consequently $K_{ISCC}$). There are many problems in using the analytic compliance formula to calculate $K_{ISCC}$, so we had proposed the experimental $K_{ISCC}$ evaluation technique in the previous report. This study has employed the slightly altered configuration of modified-WOL specimen made of weldable structural stee(BS360-50D). With these specimens, stress-corrosion tests have been performed in $H_2S$ gas saturated 20% HCl solution. Through the test, the problems as mentioned earlier have been discussed again, and the proposed evaluation technique has been verified. And the stress-corrosion cracks and hydrogen blisters have been investigated in the initiation step with the aids of metallurgical micrographs, SEM fractographs, and EPMA analysis. The inclusions segregated in the mid-thickness region traps hydrogen to produce the hydrogen blistering. The applied or residual stress does not contribute the occurrence of the blister. Hydrogen absorbed into the mid-thickness region is consumed to produce the blistering so that stress-corrosion crack could hardly be detected at that region. The stress-corrosion cracks initiate from the inclusions and propagate in radial pattern. And the initiation site is remote from the crack tip and is inclined from the crack plane, which is assumed to be caused by the triaxial stress and the amount of the absorbed hydrogen.

• 한국건축시공학회지
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• 제14권5호
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• pp.397-405
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• 2014

극한 염해환경에서 철근보강 지오폴리머 시험체의 외부전원법 전기방식 특성을 평가를 위하여 일련의 촉진실험을 실시하였다. 동시에 같은 조건의 보통 시멘트 콘크리트도 제조하여 비교 검토하였다. 환경조건은 침지대, 간만대, 그리고 크랙을 상정하였다. 지오폴리머는 밀실한 재료적 특성에 기인한 열화인자 침투 저항 증대에 의해 자연전위 뿐만 아니라 촉진 종료 후의 부식면적에서도 상당히 우수한 방식 성능이 있는 것으로 밝혀졌으며 향후 제작 양생 등의 문제를 개선함으로써 해양구조물로써의 활용이 다양해질 것으로 기대된다.