• Title/Summary/Keyword: Fiber pull Out

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Interfacial and Pull-out Properties of PVA and PET Fiber with UV Irradiation in Cementitious Composites (시멘트 복합체 내에서 UV처리에 따른 PVA 및 PET섬유의 계면 및 매입인발특성)

  • Jeon, Esther;Lee, Sang-Soo;Yun, Hyun-Do
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.401-404
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    • 2006
  • Much of requirements to the civil and building structures have been changed in accordance with the social and economic progress. Ductility of high performance fiber reinforced cementitious composites(HPFRCCs), which exhibit strain hardening and multiple crackling characteristics under the uniaxial tensile stress is drastically improved. In HPFRCC application, PVA fiber has been dominantly used as a reinforcement because of its excellent alkali resistant nature as well as high strength. But the inherent strong hydrophilicity of PVA fiber promotes the moisture absorption in cement matrix and thus it may cause the corrosion of steel structure. Therefore, it is necessary to control the interfacial adhesion of cement composites. In present study, to control the interfacial adhesion of the cementitious composites reinforced by PVA fiber, UV irradiation of the PVA fiber were performed and their effects on the adhesion property and general characteristics were investigated extensively.

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Effect of Strain Rate on Tensile Behavior of Hybrid Fiber Reinforced Cement-based Composites (하이브리드 섬유보강 시멘트복합체의 인장거동에 미치는 변형속도의 영향)

  • Son, Min-Jae;Kim, Gyu-Yong;Lee, Bo-Kyeong;Lee, Sang-Kyu;Kim, Gyeong-Tae;Nam, Jeong-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.122-123
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    • 2017
  • In this study, the tensile behavior of single and hybrid fiber reinforced cement composite according to strain rate was evaluated. Experimental results, in the strain rate 10-6/s, fiber reinforced cement composite showed improved of tensile strength and decrease of strain at peak stress as SSF volume content increased. In the strain rate 101/s, the single and hybrid reinforced cement composite' s tensile properties are improved, because of the improved bond strength between the fiber and matrix. And hybrid fiber reinforced cement composite showed high energy absorption capacity, because the SSF prevented the cracking and fracture of the surrounding matrix when during the HSF pull-out.

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Strain Rate Effect on the Tensile Properties of Steel Fiber Hybrid Reinforced Cement Composites (강섬유를 하이브리드 보강한 섬유보강 시멘트복합체의 인장특성에 미치는 변형속도의 영향)

  • Kim, In-Ho;Kim, Gyu-Yong;Lee, Sang-Kyu;Son, Min-Jae;Kim, Gyeong-Tae;Nam, Jeong-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.87-88
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    • 2018
  • In this study, the tensile properties of single and hybrid fiber reinforced cement composite according to strain rate was evaluated. Experimental results, in the strain rate 10-6/s, fiber reinforced cement composite showed improved of tensile strength and decrease of strain at peak stress as SSF volume content increased. In the strain rate 101/s, the single and hybrid reinforced cement composite's tensile properties are improved, because of the improved bond strength between the fiber and matrix. And hybrid fiber reinforced cement composite showed high energy absorption capacity, because the SSF prevented the cracking and fracture of the surrounding matrix when during the HSF pull-out.

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A Study on Behavior of Novel Non-Metallic Anchoring System for FRP Tendons (FRP 긴장재의 비금속 정착 시스템의 거동에 관한 연구)

  • 서관세;조병완;이계삼;김영진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.983-988
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    • 2000
  • Anchoring systems with structural stability and endurance have been one of the most important elements for PSC structures, especially for the structures using non-corrosive FRP tendons. FRP tendons are in increasing use for underground and coastal structures constantly contacted with fresh water or sea water because of their superiority to metallic ones in corrosion-resistance. In this study new non-metallic anchoring system for FRP tendons has been tested and investigated. The newly developed anchoring system utilizes FRP pipes and HEM (Highly Expansive Mortar). The major factors considered in this experiment were expansive pressure of HEM during its hydration and the strength of GFRP(Glass Fiber Reinforced Plastic) Pipe. Anchoring forces of the new anchoring system were investigated from the pull-out testes. The authors analyzed pull-out procedures of the FRP tendons in the various pipe filled with HEM and suggested an improved idea to develop novel non-metallic anchoring system for FRP tendons

Temperature Effect on Impact Fracture Behavior of GF/PP Composites (GF/PP 복합재료의 충격파괴거동에 대한 온도효과)

  • Koh, Sung-Wi;Um, Yoon-Sung
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.41 no.1
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    • pp.78-84
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    • 2005
  • The main goal of this work is to study the effects of temperature and volume fraction of fiber on the Charpy impact test with GF/PP composites. The critical fracture energy and failure mechanisms of GF/PP composites are investigated in the temperature range of 60^{\circ}C$ to -50^{\circ}C$ by impact test. The critical fracture energy increased as the fiber volume fraction ratio increased. The critical fracture energy shows a maximum at ambient temperature and it tends to decreases as temperature goes up or goes down. Major failure mechanisms can be classified such as fiber matrix debonding, fiber pull-out and/or delamination and matrix deformation.

Variation of Mechanical Properties by Carbon Fiber Volume Percent of Carbon Fiber Reinforced Reaction Bonded SiC (탄소섬유 강화 반응소결 탄화규소의 탄소섬유 첨가량에 따른 기계적 특성 변화)

  • Yun, Sung-Ho;Yang, Jin-Oh;Cho, Young-Chul;Park, Sang-Whan
    • Journal of the Korean Ceramic Society
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    • v.48 no.5
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    • pp.373-378
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    • 2011
  • The composite added with surface-coated chopped carbon fiber showed the microstructure of a 3 dimensional discretional arrangements. The fiber reinforced reaction bonded silicon carbide composite, containing the 50 vol% carbon fiber, showed the porosity of < 1 vol%, 3-point bending strength value of 250MPa and fracture toughness of 4.5 $MPa{\cdot}m^{1/2}$. As the content of carbon fiber was increased from 0 vol% to 50 vol% in the composite, fracture strength was decreased due to the increase of carbon fiber, which has a less strength than SiC and molten Si. On the other hand, the fracture toughness was increased with increasing the amount of carbon fiber. According to the polished microstructure, carbon fiber was shown to have a random 3 dimensional arrangement. Moreover, the fiber pull-out phenomenon was observed with the fractured surface, which can explain the increased fracture toughness of the composite containing high content of carbon fiber.

Reinforcing System(MFRI) for Concrete Structure using FRP ROD & High-performance Mortar (섬유복합재봉(FRP ROD)과 고강도 모르터를 이용한 철근 콘크리트 구조물의 휨 보강공법(MFRI) 공법)

  • Bae Ki-Sun;Park Sing-Hun;Lee Sang-Uk
    • Composites Research
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    • v.18 no.4
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    • pp.59-65
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    • 2005
  • This report is on the Reinforcing System(MFRI) for Concrete Structure using FRP ROD & High-Performance Mortar. The main characteristic of this system is as follow. First, the fiber rods in this system have seven times greater tensile strength than general reinforcing steel bars(re-bar) and the weight is a fifth lighter. Camels coated on the fiber rods' surfaces to improve adhesive strength and pull-out strength. Second, high strength shotcrete mortar is has very good workability and low rebound rate. After installing the Fiber Rods, Shotcrete mortar Is applied or sprayed to finish reinforcement. Finally, MFRI system has excellent fire-resisting performance and sogood tolerance against external environment by inserting fiber rods and reinforcing materials into mortar which has high compressive strength. It is applied to bridge slab, utility box and tunnel of civil engineering works, and beam and slab of building structures.

High Performance Fiber Reinforced Cement Composites with Innovative Slip Hardending Twisted Steel Fibers

  • Kim, Dong-Joo;Naaman, Antoine E.;El-Tawil, Sherif
    • International Journal of Concrete Structures and Materials
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    • v.3 no.2
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    • pp.119-126
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    • 2009
  • This paper provides a brief summary of the performance of an innovative slip hardening twisted steel fiber in comparison with other fibers including straight steel smooth fiber, high strength steel hooked fiber, SPECTRA (high molecular weight polyethylene) fiber and PVA fiber. First the pull-out of a single fiber is compared under static loading conditions, and slip rate-sensitivity is evaluated. The unique large slip capacity of T-fiber during pullout is based on its untwisting fiber pullout mechanism, which leads to high equivalent bond strength and composites with high ductility. Due to this large slip capacity a smaller amount of T-fibers is needed to obtain strain hardening tensile behavior of fiber reinforced cementitious composites. Second, the performance of different composites using T-fibers and other fibers subjected to tensile and flexural loadings is described and compared. Third, strain rate effect on the behavior of composites reinforced with different types and amounts of fibers is presented to clarify the potential application of HPFRCC for seismic, impact and blast loadings.

Surface Modification Effect and Mechanical Property of para-aramid Fiber by Low-temperature Plasma Treatment (저온 플라즈마 처리를 이용한 파라 아라미드 섬유의 표면 개질 효과 및 역학적 특성(2))

  • Park, Sung-Min;Son, Hyun-Sik;Sim, Ji-Hyun;Kim, Joo-Young;Kim, Taekyeong;Bae, Jin-Seok
    • Textile Coloration and Finishing
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    • v.27 no.1
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    • pp.18-26
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    • 2015
  • para-aramid fibers were treated by atmosphere air plasma to improve the interfacial adhesion. The wettability of plasma-treated aramid fiber was observed by means of dynamic contact angle surface free energy measurement. Surface roughness were investigated with the help of scanning electron microscopy and atomic force microscopy. The tensile test of aramid fiber roving was carried out to determine the effect of plasma surface treatments on the mechanical properties of the fibers. A pull-out force test was carried out to observe the interfacial adhesion effect with matrix material. It was found that surface modification and a chemical component ratio of the aramid fibers improved wettability and adhesion characterization. After oxygen plasma, it was indicated that modified the surface roughness of aramid fiber increased mechanical interlocking between the fiber surface and vinylester resin. Consequently the oxygen plasma treatment is able to improve fiber-matrix adhesion through excited functional group and etching effect on fiber surface.

Effect of Water Absorption on Fatigue Crack Growth Behavior of E-Glass/Polyerter Composite (E-Glass/Polyester 복합재료의 피로균열성장거동에 미치는 흡습의 영향)

  • Kim, Yon-Jig;Kweon, Il-Hyun;Lim, Jae-Kyoo;Jeong, Se-Hui
    • Korean Journal of Materials Research
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    • v.3 no.1
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    • pp.84-94
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    • 1993
  • This paper deals with the fatigue properties of chopped strand glass mat/polyester composite to understand the effect of water absorption on fatigue behavior of GFRP. The fatigue crack in the both no water and a water absorption materials initiated at the initial of cycle. Thereafter, it was divided with two regions that one decreased with the crack extension and the other increased with the crack extension. The absorption of distilled water degrades the bond strength between fiber and matrix, there, by the tendency of fiber pull-out is increased in perpendicular to crack growth deirection and the debonding of fibers increased to the place which is parallel to crack growth direction. Therefore, the reduction of fatigue strength was caused by these factors.

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