• Title/Summary/Keyword: high performance fiber reinforced cementitious composites

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Multiple Cracking Model of Fiber Reinforced High Performance Cementitious Composites under Uniaxial Tension

  • Wu, Xiangguo;Han, Sang-Mook
    • International Journal of Concrete Structures and Materials
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    • v.3 no.1
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    • pp.71-77
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    • 2009
  • A theoretical model of multiple cracking failure mechanism is proposed herein for fiber reinforced high performance Cementitious composites. By introducing partial debonding energy dissipation on non-first cracking plane and fiber reinforcing parameter, the failure mechanism model of multiple cracking is established based on the equilibrium assumption of total energy dissipation on the first crack plane and non-first cracking plane. Based on the assumption of the first crack to be the final failure crack, energy dissipation terms including complete debonding energy, partial debonding energy, strain energy of steel fiber, frictional energy, and matrix fracture energy have been modified and simplified. By comparing multiple cracking number and energy dissipations with experiment results of the reference's data, it indicates that this model can describe the multiple cracking behavior of fiber reinforced high performance cementitious composites and the influence of the partial debonding term on energy dissipation is significant. The model proposed may lay a foundation for the predictions of the first cracking capacity and post cracking capacity of fiber reinforced high performance cementitious composites and also can be a reference for optimal mixture for construction cost.

W/C Ratio Effects on Mechanical Properties of High Performance hybrid SC and PE Fibers Reinforced Cement Composites (물-시멘트비에 따른 하이브리드 섬유보강 고인성 시멘트 복합체의 역학적 특성)

  • Yun, Hyun-Do;Kim, Sun-Woo;Cheon, Esther;Lee, Sang-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.118-121
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    • 2006
  • The research reported here is concerned with the effects of the fiber combination condition and water/cement ratio on the mechanical properties of high performance fiber-reinforced cementitious composites(HPFRCC). An experimental investigation of the behavior of steel cords(SC) and SC and Polyethylene(PE) hybrid fiber reinforced cementitious material under compressive and tensile loading is presented. In this experimental research, the tensile and compressive strength and strain capacity of HPFRCC were selected using the cylindrical specimens. The results show that W/C ratio is a significant effect factor on the compressive and tensile performance of HPFRCC. The envelope curve concept applies to hybrid fiber-reinforced cementitious composites in tension just as it does to compressive stress-strain curve of fiber-reinforced cement composites. For practical purposes, the tensile envelope curve may be taken to be the same as the monotonic tensile stress-strain curve.

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Dynamic tensile behavior of SIFRCCs at high strain rates

  • Kim, Seungwon;Park, Cheolwoo;Kim, Dong Joo
    • Computers and Concrete
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    • v.26 no.3
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    • pp.275-283
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    • 2020
  • Reinforced concrete (RC) does not provide sufficient resistance against impacts and blast loads, and the brittle structure of RC fails to protect against fractures due to the lack of shock absorption. Investigations on improving its resistance against explosion and impact have been actively conducted on high-performance fiber-reinforced cementitious composites (HPFRCCs), such as fiber-reinforced concrete and ultra-high-performance concrete. For these HPFRCCs, however, tensile strength and toughness are still significantly lower compared to compressive strength due to their limited fiber volume fraction. Therefore, in this study, the tensile behavior of slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs), which can accommodate a large number of steel fibers, was analyzed under static and dynamic loading to improve the shortcomings of RC and to enhance its explosion and impact resistance. The fiber volume fractions of SIFRCCs were set to 4%, 5%, and 6%, and three strain rate levels (maximum strain rate: 250 s-1) were applied. As a result, the tensile strength exceeded 15 MPa under static load, and the dynamic tensile strength reached a maximum of 40 MPa. In addition, tensile characteristics, such as tensile strength, deformation capacity, and energy absorption capacity, were improved as the fiber volume fraction and strain rate increased.

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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Tension Stiffening of High Performance Fiber-Reinforced Cementitious Composites (고인성 섬유보강 시멘트 복합체의 인장강성)

  • Yun Hyun-Do;Yang Il-Seung;Han Byung-Chan;Hiroshi Fukuyama;Cheon Esther;Kim Sun-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.441-444
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    • 2004
  • This paper presnets the tensile behavior of 8 high performance fiber-reinforced cementitious composites (HPFRCCs) members, each reinforced with one deformed bar 16mm in diameter. The variables included HPFRCC(Ductal, steel cord and polyethylene hybrid fiber, PE fiber) versus normal concrete. Fibers used in HPFRCC significantly increased tensile strength, ductility, and tension stiffening of cementitious materials. For HPFRCC, after first cracking, tensile load continue to rise without fracture localization. Sequentially developed parallel cracks contributed to the inelastic strain at increasing stress level. After yielding of the reinforcing bars, HPFRCC showed increases in loads with increasing strains.

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The Evaluation of Flexural Performance of Beam of Repair as High Toughness Cementitious Composites (고인성 시멘트 복합체에 의해 보수된 보 부재의 내하력 평가)

  • Ryu, Gum-Sung;Koh, Kyung-Taeg;Park, Jung-Jun;Ahn, Ki-Hong;Yoon, Pil-Yong;Kim, Jin-Su
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.625-628
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    • 2006
  • In this study, the beam which is repaired as high toughness cementitious composites evaluated on flexural performance. As for the test results, it was found that high toughness performance of beams of the repair as high toughness cementitious composites showed more better than the existing repair method and demonstrated about 95% semi-reinforcement to compare with reinforcement of carbon fiber sheets of one layer without interface and brittle failure. Therefore, appling on using PVA fiber reinforced high toughness cementitious composites, the repaired concrete structures can be increased to flexural performance.

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Evaluation on Flexural Capacity of Reinforced Concrete Beams with Ultra-High Performance Cementitious Composites (UHPCC를 사용한 철근 콘크리트 보의 휨강도 평가)

  • Kang, Su-Tae;Park, Jung-Jun;Koh, Gyung-Taek;Kim, Sung-Wook
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.5
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    • pp.81-90
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    • 2008
  • This paper concerns the flexural capacity of reinforced concrete beams with ultra-high performance cementitious composites(UHPCC). It was investigated if the existing equations to estimate the flexural capacity of reinforced fiberous concrete beams are applicable with the experiments including lightly reinforced concrete beams. The reinforcing effect when the steel fiber reinforced concrete was used in beams was also estimated. The results showed that the equation to predict the flexural capacity of reinforced steel fiber concrete by ACI 544 committee didn't have a good agreement with the test results and underestimated the flexural capacity in especially lightly reinforced beams with under 1.5% reinforcement ratio. the enhancement of flexural capacity was quite considerable in lightly reinforced beams when the steel fiber reinforced concrete was used. A equation to predict the reinforcing effect of steel fiber in reinforced steel fiber beams was developed. the equation was proposed as a function of both the characteristics of steel fiber and reinforcement ratio.

Effect of Strain Rate on the Mechanical Properties of High Performance Fiber-Reinforced Cementitious Composites (재하속도에 따른 고성능 섬유보강 시멘트 복합체의 역학적 특성)

  • Yun Hyun-Do;Yang Il-Seung;Han Byung-Chan;Hiroshi Fukuyama;Cheon Esther;Kim Sun-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.29-32
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    • 2004
  • An experimental investigation of the behavior of steel cords(SC) and SC and Polyethylene(PE) hybrid fiber reinforced cementitious material under compressive and tensile loading is presented. In this experimental research, the tensile and compressive strength and strain capacity of high performance fiber-reinforced cementitious composites(HPFRCC) were selected using the cylindrical specimens. Uniaxial compressive and tensile tests have also been carried out at varying strain rates to better understand the behavior of. HPFRCC and propose the standard loading rate for compressive and tensile tests of new HPFRCC materials. The results show that there is a substantial increase in the ultimate compressive and tensile strength with increasing strain rate.

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Flexural toughness density of High Performance Fiber Reinforced Cementitious Composites (고인성 섬유보강 시멘트 복합재료의 휨인성 밀도)

  • Kim, Dong-Joo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.401-402
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    • 2010
  • This research initially suggest flexural toughness density as a key parameter describing energy absorption capacity of High Performance Fiber Reinforced Cementitious Composites [HPFRCC] regardless of the size of specimen. Two types of high strength steel fibers, Hooked and Twisted fiber, were used in two types of flexural specimen ($100{\times}100{\times}350mm^3$ and $150{\times}150{\times}500mm^3$) to estimate and validate the flexural toughness density.

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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.