• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.119-126
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• 2009

This study investigated the fire resistance of RC columns applying Fiber addition method, Fire board attaching method, and Fire proof sparying method. The results were summarized as following. The test showed that increase of fiber content, as expected, decreased the fluidity of fresh concrete, but for the types of fiber, the specimens containing nylon(NY) was favorable. The incline of fiber content also affected on the air content of concrete, which the specimens adding polypropylene(PP) fiber was the lowest, followed by a less decrease in polyvinyl alchhol(PVA) and then NY respectively. For the compressive strength at 28days, it was over 50MPa and showed slight increasing tendency by rising fiber contents. After the fire test completed, control concrete exhibited the severe demage, while the specimens containing more than 0.05vol.% of PP and NY was able to protect from spalling. In the case of splay, the partly spalling occurred at the all finishing material, however the RC columns were protected from spalling. For the methods attached with boards, all RC columns were protected except the dry attaching method. The reduced weight ratio was favorable because it was below 8 % except for plain concrete.

• Journal of the Korea Institute of Building Construction
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• v.20 no.3
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• pp.235-243
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• 2020

In recent years, the use of high-strength concrete has increased with increasing height and enlarging scale of the buildings However, it has been pointed out that the use of high-strength concrete is the most serious problem compared to ordinary concrete in terms of the spalling of concrete cross sections caused by fires. For this reason, fiber cocktail methods, which are made of polypropylene fibers, nylon fibers, etc., are mainly used to improve the fire resistance performance. However, the majority of research on high-strength concrete to which the fiber cocktail method was applied is mainly focused on the effect of reducing spalling, and few studies have investigated and analyzed the effect of micropores produced by melting PP fibers on the long-term durability of high-strength concrete after a fire. Therefore, in this study, the effect of micropores on the depth of carbonation was examined through carbonation tests and microstructure analysis, assuming high-strength concrete to which fiber-mixed construction method was applied, which caused fire damage.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.465-471
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• 2009

To prevent the explosive spalling of the high strength concrete and control the rise of temperature in the steel rebar during fire, a fiber cocktail method has been proposed simultaneously with the use of polypropylene and steel fiber. After applying the fiber cocktail (polypropylene and steel fibers) into the mixture of high strength concrete with a compressive strength of between 40 and 100 MPa and evaluating the thermal properties at elevated temperatures, the fire test was carried out on structural members in order to evaluate the fire resistance performance. Two column specimens were exposed to the fire without loading for 180 minutes based on the standard curve of ISO-834. No explosive spalling has been observed and the original color of specimen surface was changed to light pinkish grey. The inner temperature of concrete dropped rapidly starting from 60mm deep. After 60 minutes of exposure to the fire, the temperature gradient of fiber cocktail reinforced high strength concrete was measured as 2.2oC/mm, which is approximately 5 times less than that of normal concrete. The final temperatures of steel rebar after 180 minutes of fire test resulted in 488.0oC for corner rebar, 350.9oC for center rebar, and 419.5oC for total mean of steel rebar. The difference of mean temperature between corner and center rebar was 137.1oC The tendency of temperature rise in concrete and steel rebar changed between 100oC and 150oC The cause of decrease in temperature rise was due to the water vaporization in concrete, the lower temperature gradient of the concrete with steel and polypropylene fiber cocktails, the moisture movement toward steel rebars and the moisture clogging.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.423-424
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• 2010

This study purpose is to develop the high fireproof concrete which applied method of combined fiber mixed with polymer powder and organic fiber which can satisfy flowability and the fire resistance properties for construction of the super tall building. According to the results, in case of polymix it is effective to the reduction of internal temperature rise and spalling resistance so it as fire resistance that is similar to existing fiber cocktail.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.53-59
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• 2018

This study analyzed the field applicability through the combination of environment-friendly grid-typed reinforcements and pre-mixed fiber with filler. The film of the grid-typed reinforcement is made by recycled PE resin. And, Ascon fiber is obtained the dispersion by pre-mixing of filler. To be able to recognize in advance the various circumstances that could arise in the construction of the road pavement layer, we conducted a basic field application test of the (Mock Up) pavement layer. As a result, it was found that the pavement with environment-friendly grid-typed reinforcement and dispersive fiber construction had improved strength, stress, and rutting resistance. It is consistent with the strength and stress results of the actual test of the mock up specimen. It is expected to perform an effective role in the safety as well as the use of environment-friendly fibers in actual construction.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.949-952
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• 2008

화재안전 신뢰성이 확보된 고강도 콘크리트 구조물의 시장 공급을 위하여 GS건설에서는 2005년 부터 고강도 콘크리트 구조물의 강도 영역별 폭렬 저감 및 거동 안전성 평가와 수치해석 방법을 통한 경제적인 설계방법를 최종 연구목표로 하여 현재까지 콘크리트 재료의 열적 특성 확보와 구조부재 화재 특성 연구를 수행해 왔다. 강도발현, 시공성, 내화성능과 경제성에 대한 분석을 해외연구 기관에 의뢰하여 섬유혼입공법을 선정한 후 이에 대한 재료의 물리적 특성과 역학적 특성 실험결과를 바탕으로 고강도 콘크리트 구조부재의 내화성능을 예측 분석할 수 있도록 비열 모델, 열전도율모델, 압축강도 모델, 탄성계수 모델을 구축하였다. 또한 기둥과 보에 대한 내화실험을 실시하여 내화성능을 평가하였으며, 이에 대한 열적 해석을 병행하여 진행하였다.

• Journal of Korean Society of societal Security
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• v.2 no.3
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• pp.55-60
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• 2009

After applying the fiber cocktail(polypropylene and steel fibers) into the mixture of high strength concrete with a compressive strength of 50 MP, the fire test was carried out on specimens in order to evaluate the fire resistance performance, such as possible explosive spalling, temperature distributions of concrete and rebar. According to an enforcement ordinance, four column specimens were exposed to the fire for 180 minutes based on the standard curve of ISO-834. No explosive spalling has been observed. The required minimum quantity of polypropylene to prevent explosive spalling is more than 0.57 kg per unit concrete volume. The comparing test results from temperature distributions of concrete and rebar has found that the difference of fiber quantity is insignificant.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.775-785
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• 2006

This study focused on the development of surface deformations of GFRP rebars with a better bond characteristic for reinforcing concrete, and simultaneously, of GFRP rebars with more simple and economic production process. This research paper describes a development and bond performance of GFRP rebar with molded deformations, which is composed of polymer resin and milled glass fiber. To determine proper mix ration of milled fibers, material test of hardened epoxy and pullout tests of GFRP rebar with various mix ratio were conducted. The test results indicate that the new strategy of using a mixture of epoxy resin and milled fiber could be successfully applied to a surface structure of GFRP rebar to enhance bond with concrete. The bearing resistance of the ribs was further enhanced by the milled fibers at mechanical and environmental loading state.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.170-171
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• 2015

본 논문에서는 내충격 방폭 성능 강화를 위해 개발된 유기계 단섬유 HPFRCC의 휨인성을 평가하였다. 유기계 단섬유 보강재는 아라미드섬유를 사용하였으며, 아라미드섬유 원사를 섬유가공 방법 중에 하나인 ATY(Air texturd yarn)공법을 통해 단섬유 형태로 제조하였다. 아라미드섬유 보강재를 혼입한 HPFRCC의 휨인성 시험을 통해 아라미드섬유의 내충격 방폭 성능 강화용 섬유보강재로의 성능을 평가하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.469-470
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• 2009

Recently, so that HSC can secure the fire resistance properties at the time of a fire in super tall building suggested method of combined fiber. Thus, there is the purpose to develop the high fireproof concrete which applied method of combined fiber which can satisfy flowability and the fire resistance properties of HSC for construction of the super tall building.