• 한국안전학회지
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• 제24권6호
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• pp.103-110
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• 2009

Since the mechanical properties of cement-based materials are time-dependent due to the prolonged cement hydration process, those of fiber reinforced concrete(FRC) may also be time-dependent. Toughness is one of important properties of FRC. Therefore, it should be investigated toughness development of FRCs with curing ages to fully understand the time-dependent characteristics of FRCs. To this end, the effect of curing ages on flexural toughness development of steel fiber reinforced concrete is studied. Three point bending test with notched beam specimen was adapted for this study. Hooked-end steel fiber(DRAMIX 40/30) was used as a fiber ingredient to investigate w/c ratio and fiber volume fraction effect on toughness development during curing. Three different water-cement ratios(0.44, 0.5 and 0.6) and fiber volume fractions(0%, 0.5% and 1%) were used as influence factors. Each mixture specimens were tested at five different ages, 0.5, 1, 3, 7 and 28 days. The study shows that flexure toughness development with age is quite different than other concrete material properties such as compressive strength. The study also shows that the toughness development trend correlates more closely to water/cement ratio than to fiber volume fraction.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.1-6
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• 1996

Cellulose fiber reinforced cement composites manufactured by the slurry-dewatering process have found broad applications in thin cement products as replacement for asbestos cement. This paper focuses on the durability characteristics of these composites under different aging conditions. The effects of wetting-drying and freezing-thaw cycles, carbonation, and exposure to hot and humid environments on the structure and properties of cellulose fiber-cement composites were investigated. The predominant mechanisms of aging in the composites were identified through investigation of structure-property relationships. Measures to control these aging mechanisms were diversed and evaluated. Refined cellulose fiber-cement composites are shown to possess excellent durability characteristics under the effects of various aging processes.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.79-80
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• 2020

This study compared and analyzed the flow and strength characteristics of cement paste according to the rate of mixing of amorphous metallic fiber as part of the research for the development of amorphous metallic fiber reinforced cement composite.

• Advances in concrete construction
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• 제9권4호
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• pp.387-395
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• 2020

This study has been carried out in two-phases to develop Fiber Reinforced Self-Compacting Concrete (FRSCC) performance. In the first phase, the composition of the quaternary composite binder compromised CEM I 42.5N (58-70%), Rice Husk Ash (25-37%), quartz sand (2.5-7.5%) and limestone crushing waste (2.5-7.5%) were optimized. And in the second phase, the effect of two fiber types (steel brass-plated and basalt) was investigated on the SCC optimized with the optimum CB as disperse reinforcement at 6 different ratios of 1, 1.2, 1.4, 1.6, 1.8, and 2.0% by weight of mix for each type. In this study, the theoretical principles of the synthesis of self-compacting dispersion-reinforced concrete have been developed which consists of optimizing structure-formation processes through the use of a mineral modifier, together with ground crushed cement in a vario-planetary mill to a specific surface area of 550 m2 / kg. The amorphous silica in the modifier composition intensifies the binding of calcium hydroxide formed during the hydration of C3S, helps reduce the basicity of the cement-composite, while reducing the growth of portlandite crystals. Limestone particles contribute to the formation of calcium hydrocarbonate and, together with fine ground quartz sand; act as microfiller, clogging the pores of the cement. Furthermore, the results revealed that the effect of fiber addition improves the mechanical properties of FRSCC. It was found that the steel fiber performed better than basalt fiber on tensile strength and modulus of elasticity; however, both fibers have the same performance on the first crack strength and sample destruction of FRSCC. It also illustrates that there will be an optimum percentage of fiber addition.

• 비파괴검사학회지
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• 제27권2호
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• pp.148-156
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• 2007

섬유복합재료의 역학적인 관점에서 볼 때 PVA-ECC (polyvinyl alcohol-engineered cementitious composite)의 섬유분산성 평가는 매우 중요한 요소이다. 그러나 PVA 섬유의 낮은 명암비 때문에 시멘트계 재료와 섬유를 구별하기가 어려우므로, PVA-ECC의 섬유분산성 평가를 하기에는 어려운 점이 있다. 이 연구에서는 이러한 문제점을 해결하기 위하여 PVA-ECC 내의 섬유분산성을 평가할 수 있는 새로운 방법을 제시하였다. 형광의 원리를 이용하여 섬유복합재료 단면에서 PVA 섬유가 초록빛을 발하는 이미지를 얻었고, PVA-ECC 시편에 대한 섬유분산성은 형광 현미경에 부착된 CCD (charge coupled device) 카메라를 통하여 얻어진 이미지를 이미지 프로세싱 기법과 통계적인 방법을 이용하여 평가하였다. 또한 형상분석을 통하여 섬유의 방향성이 분산성에 미치는 영향을 파악하였으며, 판별함수기법과 분수령 알고리즘을 이용하여 섬유 검출 성능을 향상시킬 수 있는 기법을 제시하였다.

• Composites Research
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• 제19권1호
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• pp.43-48
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• 2006

High performance fiber reinforced cement composites have better performances than traditional cement based materials, therefore, have been expected as new construction applications such as the materials for construction & bridge structure, repair and rehabilitation applications, anti-collapse applications, anti-noise applications etc. However, they have lots of the problems such as material design, fabrication method and structural analysis. Also, the most serious problems of High performance fiber reinforced cement composites have been expensive initial cost, lack of long-term exposure data. As a result, it is needed that the efforts for lowering the initial cost and accumulation of long-term exposure. There has been hardly assessment results of life cycle cost for HPFRCC in construction field, but some papers showed that total life cycle cost could be profitable if the initial cost could be reduced.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.87-90
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• 2005

An experimental investigation on the strength and behaviour of reinforced concrete columns using high performance fiber reinforced cement composites has been carried out. The columns were subjected to monotonic axial compression until failure. The variables in this study are the combination ratio of steel cord(SC) and Polyethylene (PE), and the volumetric ratio of transverse reinforcement Test results showed that the fibers, when used in a hybrid form, could result in superior composite performance compared to their individual fiber reinforced cement composites.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.631-634
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• 2004

An experimental investigation on the strength and behaviour of reinforced concrete columns using high performance fiber reinforced cement composites has been carried out. The columns were subjected to monotonic axial compression until failure. The variables in this study are the combination ratio of steel cord(SCI) and polypropylene(PP), and the volumetric ratio of transverse reinforcement Test results showed that the fibers, when used in a hybrid form, could result in superior composite performance compared to their individual fiber reinforced cement composites.

• 콘크리트학회지
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• 제3권3호
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• pp.101-110
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• 1991

이 연구는 피치계 탄소섬유 보강 플라이애쉬.시멘트 복합체의 여러 가지 특성을 실험적으로 구명하고, 그 제조방법을 제시한 것이다. 복합체는 조강시멘트, 시리카 분말, 스티렌 부타디엔 러버 라텍스, 기포제와 탄소섬유 및 플라이애쉬를 사용하여 제조하였고, 배합조건별로 그 특성을 검토하였다. 연구결과, 경량 탄소섬유 보강 플라이애쉬.시멘트 복합체의 압축강도, 인장강도, 휨강도, 흡수성 및 특수성 그리고 건조수축과 같은 물리적.역학적 성질은 스티렌 부타디엔 러버 라텍스를 첨가하므로써 현저히 개선되었으며, 아울러 복합체를 제조하는데는 기건양생보다 오토클래브 양생이 유리한 것으로 나타났다. 이결과, 앞으로 경량 탄소섬유 보강 플라이애쉬.시멘트 복합체를 이용한 프리캐스트 제품의 개발에 크게 기여할 수 있을 것으로 기대된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.336-341
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• 1998

Steel fiber reinforced concrete(SFRC) is a composite material possessing many physical and mechanical properties which are distinct from unreinforced concrete. The use of steel fiber reinforcement to improve the flexural and tensile strengths, extensibility and toughness of ordinary cement concrete is well known at present, but reinforcement of polymer concrete with steel fibers has been hardly reported untill now. The objective of this study was to improve the properties of the polymer concrete by addition of steel fibers. In this paper steel fiber reinforced polymer concrete is prepared with various steel fiber contents and aspect ratio($\ell$ /d), and their mechanical properties were investigated experimentally.