• Proceedings of the Korean Geotechical Society Conference
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• 2002.11b
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• pp.18-30
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• 2002

이암 및 셰일은 점토를 함유하고 있어 풍화작용을 받을 경우 공학적 성질이 급격히 변화하여 강도 저하, 내구성저하현상 및 토사와 유사한 거동을 보이는 등 토목공사에 위험한 요소가 되고 있다. 풍화된 시료엔 대한 실험용 시료 가공이 어렵고 적용 가능한 실험법이 적어 공학적 특성이나 거동을 정량적으로 파악하는 기법이 다른 암종에 비해 극히 제한된다. 현재까지 강도측정과 같은 일반적인 물성의 단순측정보다는 내구성을 분석하는 슬레이킹 내구성 시험 (Slake durability test), Modified Jar test, 팽창율 측정시험 (Swelling test) 등의 정량화 시험법이 주로 사용되고 있으며 국내 현장에서도 적용을 권장할 수 있다. 이러한 실험치의 해석에서 단일 실험치 (예: 팽창율)만으로 지질공학적 특성을 파악하는 경우 잘못된 판단을 할 수도 있으므로, X선 회절분석시험 (XRD: X-Ray Diffraction Test), TG-DTA분석, 주사전자현미경 (SEM: Scanning Electron Microscope) 이미지 분석, 투수계수 측정실험 등도 함께 수행하여 실험결과를 종합적으로 해석하는 것이 바람직하다.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.315-324
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• 2016

Because of a fissility characteristics of shale in the Gyoungsang super-group, it breaks down to debris when daylighted by construction work and causes a slope unstability. To assess the durability property of shale, a series of slake durability tests was conducted by controlling test conditions such as shape of specimen, number of specimen, revolution speed, revolution number, drying temperature and pH of submerging liquid. For the specimen shape, cube one showed relatively lower durability index than cuboid and/or fan shape one. The test with the more number of specimens showed the less durability index because of a higher friction among specimens in the drum. The durability index is linearly decreased by increasing the total number of revolution, while the revolution velocity could not affect the index. And the durability index is also decreased by increasing the drying temperature of specimen and by decreasing the pH of submerging liquid. Because the durability index of shale is almost similar to that of crystalline rocks, the disintegration characteristics of shale could not be assessed by the slake durability test recommended by ISRM, and thus a new test method by changing the total revolution number may be required for the shale having fissility characteristics.

• Prospectives of Industrial Chemistry
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• v.22 no.4
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• pp.1-12
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• 2019

최근 전 세계적으로 이상화탄소 배출규제에 대응하기 위해 신에너지를 동력원으로 하는 자동차에 관심이 증가하고 있다. 그중 이온 교환막 연료전지(PEMFC)는 내연기관을 대신에 자동차 동력원으로 많이 사용되어지고 있으며 양산화를 위한 노력을 전 세계적으로 하고 있다. 하지만 이러한 수소 자동차가 시장과 소비자의 요구 조건을 충족하기 위해서는 내구성을 개선하여야 한다. 현재 선진사들을 중심으로 수소 자동차의 내구성을 개선하기 위해 노력하지만, 대부분 실험적 방법으로 내구성의 분석 및 평가를 수행하고 있다. 하지만, 이러한 방법은 비용과 시간이 많이 들기 때문에 경제적이지 못하다. 본 기고문에서는 내구성에 영향을 받는 인자, 연료전지 시스템 내구성을 예측하고 평가할 수 있는 수소 자동차 내구성 모델 개발에 필요한 수식에 관한 연구, 그리고 내구성 개선을 위한 해석적 방법(simulation)에 관한 연구 동향을 소개하고자 한다.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.773-784
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• 2008

Even if the exploitation of copper slag produced during the smelting process of copper as aggregate for construction purpose has been permitted since 2004 in Korea, the lack of sufficient data enabling to evaluate its long-term stability that is its durability has to date impeded its application. This study intends to investigate experimentally the durability characteristics of 18 and 27 MPa-class commercial concretes in which natural sand (fine aggregates) has been partially replaced by copper slag through accelerated and exposure tests so as to provide bases promoting the application of copper slag concrete. The experimental results revealed insignificant difference of the durability characteristics in most of the mix proportions in which 30% of natural sand was replaced by copper slag. In the case where crushed sand was adopted, tests verified similar characteristics for replacement ratio of 50%. Particularly, the results of the exposure test conducted during 8 years demonstrated that equivalent level of durability was secured compared to the case using natural sand. In the case of 18MPa-class lower grade concrete, exposure test verified also that the physical lifetime similar to 50 years could be secured until carbonation reaches cover depth of 20 mm.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.79-86
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• 2007

The corrosion durability of steel bridge coatings, such as organic and metallic coatings, is often evaluated by field exposure tests, but such tests take from several years to decades to complete. As a potential method for fast corrosion testing, accelerated exposure tests were considered in this study. The S6-cycle accelerated exposure test, specified in the Japanese Industrial Standards (JIS K5621), was carried out on uncoated structural steels for 30, 60, 90, 120 and 150 days, and the resultant weight loss was determined. The weight loss was compared with that obtained from previous field exposure tests, and acceleration factors of the S6-cycle test to field exposure test sites were determined. The application of the S6-cycle accelerated exposure tests to field environments was presented based on the acceleration factor and the amount of flying salt.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.140-148
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• 2016

This study examined the durability of face-slab concrete in Concrete-Faced Rock-filled Dams(CFRDs). The durability of face-slab concrete can be improved by optimizing the amount of fly ash in the cement mixture. Durability tests including plastic shrinkage, permeability, abrasion resistance, and repeated freezing and thawing were done on face-slab concrete specimens with different amounts of fly ash and blended PVA(Poly Vinyl Alcohol) fibre. When the effect of the fly ash content on concrete durability was evaluated, the results showed that a 15% fly ash content and 0.1% blended PVA fiber yielded the optimum durability level for concrete-faced rock-filled dams.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.275-276
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• 2001

담수어류의 종묘 생산시 담수산 rotifer, Brachionus calyciflorus는 동물 먹이생물로 많이 이용되고 있다. 특히, 유성생식에 의해 형성된 이종의 내구란은 두터운 2차 난막으로 싸여져 있어 외부환경이 부화에 적합하지 않으면 강한 내구성을 지니고 있어 휴면상태를 계속 유지한다. 이러한 내구란은 종의 유전적 형질을 효율적으로 보관 할 수 있을 뿐만 아니라 대량배양용 seed와 생태 독성학의 실험재료로 이용할 수 있다. 또한 Artemia cyst처럼 쉽게 부화시켜 자어에 직접 공급할 수 있는 장점을 가지고 있다. (중략)

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.305-311
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• 2010

The industrial by-product market has increased at a geometric rate worldwide with the rapid economic growth. At present time, conventional disposal methods of industrial by-products in Korea including landfill, incineration and storage already have reached their limits. In this study, the industrial by-products such as fly ash and silicafume were used as mineral admixtures, which are commonly added to concrete mix to inhance the economic efficiency, long-term strength and durability of concrete, to determine the optimized mix proportion of high performance shotcrete. Through the series of tests (compressive strength test, accelerated chloride ion penetration test, measurement of chloride diffusion coefficient). The results of the study showed that the proposed mix proportions satisfied the requirements of domestic as well as international guidelines for shotcrete, with a higher durability than the existing shotcrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.156-162
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• 2008

The fatigue durability test using the actual size beam was performed with a cramp joint in order to apply to the highway bridge deck slab. Three types of beam were investigated for durability performance by considering stress conditions in real bridge deck slabs, 1) A beam with major shear force applied at the joint (RC Type) 2) A beam with major bending moments applied at the joint (PSC Type) 3) A beam with the pure shear applied at the joint. The experiment for beams with cramp joints showed that the cramp joint had enough durability for fatigue regardless of the overlaid length of the looped distribution bars under the current design strength level. Moreover, it was clarified that the enough durability for fatigue under the load repetition was achieved by increasing the joint span grater than 1.5D with the consideration of the deformation due to reduction in joint stiffness.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.301-302
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• 2022

최근 들어 염해, 콘크리트의 탄산화, 동결융해 등의 열화요인 의하여 발생할 수 있는 콘크리트의 내구성에 대한 다양한 연구가 진행되고 있는데, 이러한 열화요인은 독립적이 아닌 복합열화의 형태로 작용하게 되는데, 열화현상을 저감하는 한 방편으로 플라이애쉬와 같은 혼화재를 사용하디도 한다. 플라이애쉬는 유동성 증진을 통한 내구성의 향상과, 수화열 저감을 통한 균열감소 및 장기강도 증진 등의 효과가 있으며, 시멘트를 대체함으로써 경제적인 효과를 유발하는 장점도 가지고 있다. 그러나 플라이애쉬는 품질편차가 크고, 경우에 따라서 미연탄소분에 의한 AE제 흡착 등으로 인한 콘크리트의 내구성 및 강도를 저하시킬 수 있는 요소를 내포하고 있으므로 사용 시 주의가 필요하다. 본 연구에서는 열화를 저감하고, 내구성을 갖는 고강도 콘크리트를 제조하기 위하여 다양한 배합비의 플라이애쉬 혼입 콘크리트를 실험한 후 그 결과를 분석·고찰함으로써 내구성 콘크리트의 제작 시 혼화재로서의 적용성 및 타당성을 검증하고자 하며, 플라이애쉬를 내구성 재료로 그 활용을 극대화하고, 다양한 플라이애쉬의 사용량과 물/결합재비(W/B)에 대하여 내구성이 높은 고강도 콘크리트 제조방법을 범용화하며, 그 품질을 평가하는 것을 목적으로 한다.