• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.491-496
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• 2001

In recent years, the research and development about the new material proceed rapidly and actively in the building industry. As building structures become bigger, higher and more specialized, so does the demand for material with higher strength. In the future, we will need to research repair and rehabilitation to make high strength concrete mixed steel fibrous building safe. The carbon fiber reinforced plastic bonding method is widely used in reinforcing the existing concrete structure among the various methods. The repair of initiate loaded reinforced high-strength concrete beams mixed steel fibrous with epoxy bonded Carbon Fiber Sheets(CFS) was investigated experimentally. The CFS thickness and length were varied to assess the peel failure at the curtailment of CFS, The behaviour of the repaired beams was represented by load-longitudinal steel strain relation and failure modes were discussed. The test results indicate that CFS is very effective for strengthening the demand beams and controlling deflections of reinforced high strength concrete beams mixed steel fibrous happen diagonal crack, the increase in the number of CFS layers over two layers didn't effect the increase in the strength of beams.

• 한국방재학회 논문집
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• 제11권1호
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• pp.1-6
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• 2011

고강도 콘크리트의 폭렬현상을 억제하여 내화 성능을 개선하기 위한 방법으로 고온에서 수증기가 콘크리트 표면으로 이동할 수 있도록 경로를 제공하여 주는 섬유를 혼입하는 방안이 있다. 섬유를 혼입하여 콘크리트의 폭렬을 억제하는 방법은 고온에 의해 콘크리트 내부에서 용융되는 섬유에 의해 만들어지는 통로가 서로 연결되어 고압의 수증기를 콘크리트 외부로 이동시킬 수 있을 때 효과가 있다. 수증기가 배출될 통로를 형성하는 섬유의 연결성에 대한 percolation 이론을 섬유혼입 고강도 콘크리트의 내화실험 결과에 적용하였다. 본 연구에서는 percolation 이론과 섬유혼입 고강도 콘크리트의 폭렬 발생의 연관성을 분석하였고, 섬유혼입 고강도 콘크리트 가상 시편을 이용하여 내부 섬유 입자가 서로 연결되어 있는 것을 입체적으로 구현하고 일정 부피비의 섬유가 혼입되었을 때 수증기 배출 통로가 확보되는 것을 확인하였다.

• 한국농공학회논문집
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• 제55권4호
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• pp.29-35
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• 2013

The objective of the current study is to evaluate the effects depending on the types of reinforcing fibers being influential in view of mechanical properties and impact resistance of hybrid fiber reinforced concrete (HFRC) for applications to precast concrete structure. Hybrid fibers applied therefor were three types such as PP/MSF (polypropylene fiber+macro synthetic fiber), PVA/MAF (polyvinyl alcohol fiber+MSF) and JUTE/MSF (natural jute fiber+MSF), where the volume fraction of PP, PVA and natural jute was applied with 0.2 %, respectively, while based on 0.05 % volume fraction of MSF. The HFRC was tested for slump, compressive strength, flexural strength and impact resistance. The test result demonstrated that mixture of such hybrid fibers improve compressive strength, flexural strength and impact resistance of concrete. Moreover, it was found that HFRCs to which hydrophilic fibers, i.e. PVA/MSF and JUTE/MSF, were mixed show more improved features that HFRC to which non-hydrophilic fiber, i.e. PP/MSF was mixed. Meanwhile, the finding that PVA/MSF HFRC exhibited better performance than JUTE/MSF HFRC was attributed from the former having higher aspect ratio than that of the latter.

• 한국건축시공학회지
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• 제8권1호
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• pp.43-48
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• 2008

Fifteen concrete specimens were mixed and tested to explore the significance and limitation of appling the polyvinyl alcohol (PVA) fiber and steel fiber with end hook to concrete. Main parameters investigated were volume fraction and length of the fibers. The measured mechanical properties of fiber reinforced concrete are analyzed according to the equivalent fiber amount index explaining the adding amount and length of fibers. Test results showed that compressive strength of fiber reinforced concrete was higher than that of concrete with no fiber by $10{\sim}20%$. The normalized splitting tensile strength and flexural strength of PVA fiber reinforced concrete were similar to those of concrete with no fiber, whereas those of steel fiber reinforced concrete increased with the increase of the equivalent fiber amount index. In particular, much higher ductile behavior was observed in steel fiber reinforced concrete than in PVA reinforced concrete, indicating that the slope of descending branch of load-displacement relationship of steel fiber reinforced concrete decreased with the increase of the volume fraction and length of the fiber.

• 한국방재학회 논문집
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• 제11권2호
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• pp.45-52
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• 2011

고강도 콘크리트의 폭렬현상을 억제하여 내화 성능을 개선하기 위한 방법으로 고온에서 수증기가 콘크리트 표면으로 이동할 수 있도록 경로를 제공하여 주는 섬유를 혼입하는 방안이 있다. 본 연구에서는 섬유혼입 고강도 콘크리트 기둥에 대한 재하 내화 실험을 수행하였고, 내부 철근의 온도분포 예측을 위한 열전달 모델과 고온에서 콘크리트 기둥의 역학적 거동에 대한 재료모델을 제시하였다. 화재 시 콘크리트 내부의 물리적인 현상과 콘크리트의 열적 특성을 고려하여 선행 연구의 재료모델을 수정하였다. 수정한 모델을 이용한 섬유혼입 고강도 콘크리트의 유한요소 해석을 실행하였고, 재하 내화실험과의 비교를 통하여 재료모델을 제안하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.37-38
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• 2023

As one of the resource recovery projects, this study aims to select natural fibers and synthetic fibers that can be used for concrete mixing among waste fibers and reuse them for the base concrete mixture. Using waste fiber, we seek a solution to the problem of reduced fluidity and hardening time of fiber-reinforced concrete and find the optimal mix of the ground concrete mixed with waste fiber.

• 한국지반신소재학회논문집
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• 제14권4호
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• pp.105-115
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• 2015

본 연구에서는 매크로섬유를 PP섬유로 대체하여 유기계 섬유들인 PVA섬유 6mm와 PP섬유 50mm로 하이브리드 보강된 콘크리트의 역학적 특성을 파악하기 위해 섬유의 체적비를 주요변수로 하이브리드 섬유 보강 콘크리트(HFRC) 4배합과 섬유가 없는 Plain콘크리트 1배합을 실험하여 비교하였다. 섬유의 체적비를 1%미만으로 제한하였다. 연구결과 유기계 섬유의 하이브리드 보강은 콘크리트의 강성 및 연성거동을 강섬유만큼 극대화시키지는 못하지만, Plain콘크리트와 비교시 매우 진전된 연성거동을 보이며 휨 인성지수와 등가휨강도 사이의 의미 있는 관계를 확인하였다. 그리고 유기계 섬유로 하이브리드 보강한 콘크리트에서도 섬유의 체적비가 증가할수록 연성이 증가하였고 섬유의 하이브리드를 위해 사용한 마이크로섬유인 PVA섬유보다 매크로섬유인 PP섬유가 콘크리트의 휨 거동에 미치는 영향이 크며, 염분침투시험에서도 섬유의 혼입이 염분침투를 억제하는 효과가 있는 것으로 확인되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.337-340
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• 2005

In this study, an effect of fiber blending on material property of Hybrid Fiber Reinforced Concrete (HFRC) was evaluated. Also, Compare and evaluates collating and mechanical property by the mixing rate of fiber for HFRC was determine. Modulus of rupture and strength effectiveness of Hybrid Fiber Reinforced Concrete mixed with macro-fiber(steel fiber) and micro-fiber(glass fiber, carbon fiber, cellulose fiber). Test result shows, in the case of mono fiber reinforced concrete. As the steel fiber mixing rate increases to 1.5$\%$, the strength effectiveness promotion rate rises. However, when is 2.0$\%$, strength decreases. In the case of hybrid fiber reinforcement concrete, synergy effect of micro fiber and macro fiber happens and higher Modulus of rupture and strength effectiveness appears than mono-fiber reinforcement concrete. Use of hybrid fiber reinforcement in concrete caused a significant influence on its fracture behavior; consequently, caused increase by mixing rate of steel fiber + carbon fiber and contributed by steel fiber + glass fiber, steel fiber + celluloid fiber in reinforcement effect in order. And was expose that steel fiber(1.5$\%$) + carbon fiber(0.5$\%$) is most suitable association.

• 한국농공학회지
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• 제44권1호
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• pp.93-102
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• 2002

Steel fiber and polymer are used widely for reinforcement material of RC structures because of its excellences of the durability, serviceability as well as mechanical properties. The purpose of this study is to investigate the shear behavior of polymer cement high strength concrete beams mixed with steel fiber. The compressive strength of concrete was based on the 100$\times$200 mm cylinder specimens. The compressive strength of concrete are 320$kgf/cm^2$, 436 $kgf/cm^2$ and 520 $kgf/cm^2$ in the 28 days. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns and fracture modes. Also, load-strain and load-deflection examined. During the test cracks were sketched against the load values according to the growth of crack. result are as follows; (1) The failure modes of the specimens are increased in rigidity and durability with mixing steel fiber and polymer. (2) The load of initial crack was similar a theory of shear-crack strength. (3) The deflection and strain at failure load of Polymer-steel fiber high strength concrete beams were increased, improving the brittleness of the high strength concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.21-22
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• 2013

Nowadays, the fiber which mixed with concrete matrix always has low adhesion with cement paste. It's difficult to use fiber to reinforce the structure. For more adding fiber in concrete would cause some problems as the low flowability and surface polishing. Further study is needed in fiber using. In this research, further study in fiber reinforced concrete has been invested. Various fibers with different properties have been used to prevent cracking. Fiber reinforced concrete's fundamental properties as slump, air content, compressive strength and tensile strength have been tested. Optimum type of the fiber and optimum addition ratio of fiber has been invested to increase the utility of the fiber which used in concrete.