• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.35-41
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• 2005

Recently, various fiber reinforced cementitious composites are used in order to solve problems of concrete as the brittleness breaking. Especially, in U.S.A., Europe, and Japan, ultra-high strength steel fiber reinforced cementitious composites(ultra-high strength SFRCC) with compressive strength in excess of 100 MPa were developed. However few studies have been investigated on the high-strength SFRCC in Korea. Therefore, in this paper, to make ultra-high strength SFRCC with the range of compressive strength 180MPa, it was investigated the constitute factors of ultra-high strength SFRCC influenced on the compressive strength. The experimental variables were water-binder ratio, replacement of silica fume, size and proportion of sand, type and replacement of filling powder, and using of steel fiber in ultra-high strength SFRCC. As a result, in water-binder ratio 0.20, we could make ultra-high strength SFRCC with compressive strength of 180MPa through using of silica fume, quartz sand with below 0.5mm filling powder and steel fiber.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.223.1-223.1
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• 2010

CFRP는 우수한 기계적 강도와 경량 특성으로 인하여 NGV/FCV용 가스를 저장하기 위한 재료로서 널리 이용되고 있다. 탄소 섬유와 에폭시로 이루어진 CFRP는 화염 노출 시 매트릭스의 열적 분해 반응에 의해 급격한 물성 변화를 일으킨다. CFRP 메트릭스가 100kW/$m^2$ 이하의 열플럭스에 노출되는 경우 표면온도 변화에 따른 용기 내부로의 열확산 메카니즘을 규명하기 위해서는 시간에 따른 경계조건의 변화를 명확히 할 필요가 있다. 본 연구에서는 Fuel bed type 가열장치의 열플럭스를 계산하였으며 계산된 열플럭스에 노출되는 CFRP 용기 표면의 온도 변화 측정 실험을 수행하였다. 또한 측정 결과를 보고된 문헌의 결과와 비교하였다.

• Journal of Korea Ship Safrty Technology Authority
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• s.38
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• pp.12-21
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• 2015

유리강화섬유(FRP,Fiber Reinforced Plastic)은 가볍고 내구성등이 우수하여 가공하기 쉬워 선박건조, 특히 어선의 건조재료로 많이 활용되고 있으나, FRP의 재료인 매트와 로빙이 인화성을 가진 수지와 접합되어 화재에는 매우 취약한 특성을 가지는 특성을 가진다. 최근 10년간의 중앙해양안전심판원의 어선화재 재결서 분석결과 전체의 약80%에 해당하는 화재사고가 기관실에서 발생하였다. 이에 새로 출범한 해양수산부는 FRP선박의 구조기준을 개정하여 총톤수10톤 이상 선박의 기관실에 대한 방화조치를 그 이하선박까지로 적용 확대하였으며, 어선구조기준 역시 행정규칙 행정예고를 통해 강화하려는 움직임을 보이고 있다. 본 지에서는 국내외 화재사고 발생현황 및 관련 규제 내용을 비교 분석하여 제시하였으며 분석결과, 일반선박의 방화조치에 대한 규제는 거의 유사하였으나 어선관련 규제의 경우, 영국의 규제가 가장 강화되어 있었으며 관련 화재사고 발생현황도 국내 및 일본과 비교해 보았을때 같은 기간 발생한 일반선의 화재발생척수 대비 어선의 화재발생척수가 적은것을 확인할 수 있었다.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.252-258
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• 2011

Nickel fiber mat was investigated as a potential structured catalyst for steam reforming of biogas in the temperature range of $600-700^{\circ}C$. The activity of as-received catalyst was very low owing to the smooth surface of fibers. Pretreatment of the catalyst by oxidation followed by reduction under methane partial oxidation condition significantly improved the catalytic activity, although degradation of the activity was found during the reaction due to oxidation and sintering. This deactivation was retarded by supplying additional hydrogen in the inlet gases or by coating $CeO_2$ over the catalyst surfaces.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.152-163
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• 2019

In this paper, effect of steel fiber inclusion, compressive strength of matrix, shear reinforcement and shear span to depth ratio on the flexural behavior of UHPFRC(Ultra High Performance Fiber Reinforced Concrete) were investigated with test of 10-UHPFRC beam specimens. All test specimens were subjected to the flexural static loading. It was shown that steel fiber significantly improve the shear strength of UHPFRC beams. 2% volume fraction of steel fiber change the mode of failure from shear failure to flexural failure and delayed the failure of compressive strut with comparatively short shear span to depth ratio. UHPFRC beams without steel fiber had a 45-degree crack angle and fiber reinforced one had lower crack angle. Shear reinforcement contribution on shear strength of beams can be calculated by 45-degree truss model with acceptable conservatism. Using test results, French and Korean UHPFRC design recommendations were evaluated. French recommendation have shown conservative results on flexural behavior but Korean recommendation have shown overestimation for flexural strength. Both recommendations have shown the conservatism on the flexural ductility and shear strength either.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.101-105
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• 2002

FRP(Fiber glass reinforced plastics) is compound with materials, which are created to combine each other materials, of which nature of mechanical and chemical are different. Even though the weight and the thickness are identic, its physical figure of characteristic changes with consisting of lay-up and work situation. It is also a method of creating after manufacturing of mould. It has feature that manufacturing of FRP runs parallel design of material with design of structure simultaneously. The rule of FRP structure is distinguished from the length of a ship and it is hard to catch the feature of structure mechanics due to identical formula and figure used for it regardless of the shape of a ship or the speed. This studying, basing on a small FRP ship, will show te fundamental data needed to design of structure analysing the feature of intensity with direction, the method of Lay-up, and the characteristic of materials of FRP.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.1-9
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• 2008

Fiber Reinforced Polymer (FRP) composites are used extensively in aerospace, marine, automotive, infrastructure, chemical processing and sporting good applications. A concern with using FRP composites in some engineering structures is their high flammability and poor fire resistance In this research, material properties of FRP composites at increasingly high temperatures was measured and verified. The obtained mechanical properties of FRP composites were performed according to ASTM D3039/D3039M and tested to a wide range of heat conditions with temperatures from Room-temp. to 300 for times up to 30 min. It is found that the mechanical properties of FRP composites dropped with increasing heat or temperature. The reduction to the properties was due mainly to thermal degradation and combustion of the polymer matrix.

• Journal of the Korean Geosynthetics Society
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• v.4 no.1
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• pp.27-36
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• 2005

Discharge capacity of the fiber mat and the fiber drain made with natural fibers abstracted from plant source was evaluated by permeability test for fiber mat and Delft type test and composite discharge capacity test using disturbed clayey soils for fiber drain. The permeability test results for environmentally friendly coconut fiber mat prove that fiber mat has outstanding permeability in substituting permeable sand. However, discharge capacity of fiber drain evaluated by conventional Delft type discharge capacity test was relatively lower than that of plastic drain board. Nevertheless, settlement and pore pressure dissipation behaviors of fiber drain and plastic drain board installed clay soil during the composite discharge capacity test were almost similar to that of plastic drain board. It is found that the natural fiber drain satisfies requiring minimum discharge capacity in substituting the conventional plastic drain board.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.198-204
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• 2019

Polymer composites are widely used as industrial materials requiring high mechanical properties. Glass fibers and fillers, which are used as a reinforcement in composites, usually have some problems such as nonuniform dispersion and poor interfacial adhesion. In this study, an acrylic acid-modified polyethylene wax was synthesized by the sequential reaction of pyrolysis of polyethylene followed by grafting with a polar acrylic acid. The acrylic acid-modified polyethylene wax was applied to polymer composites of the polyamide matrix and glass fiber reinforcement. The effect of acrylic acid-modified polyethylene wax on physical properties of polyamide based composites was thoroughly investigated.

• Polymer(Korea)
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• v.24 no.6
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• pp.845-853
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• 2000

The optimum cure cycle and carbonization condition were selected by the DSC and TGA analysis and green bodies were prepared by the method of hot press molding and then carbonized up to 140$0^{\circ}C$. Additives such as graphite powder, carbon black, milled carbon fiber and carbon fiber mat, which were considered to be effective in improving the interlaminar shear strength, were also added to check their effects on the density and porosity of products. Then, their relations with mechanical properties such as ILSS and flexural strength were investigated. The composites added 9 vol% of graphite powder showed the greatest values of ILSS and flexural strength. Otherwise, in case of adding carbon black, the composites showed the slight improvement of ILSS at its contents of 3 vol% but the flexural strength was decreased. When milled carbon fiber and carbon fiber mat were added, the lack of resin and the heat shrinkage during the carbonization caused the delamination, resulting in decreasing the density, ILSS and flexural strength.