• Title, Summary, Keyword: steel fiber reinforced concrete

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Long-Term Characteristics on Flexural Performance of Steel Fiber Reinforced Concrete Continuous Slab (강섬유보강콘크리트 연속슬래브 휨성능의 장기거동 특성)

  • Hong, Geon-Ho;Jung, Seong-Won
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.10
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    • pp.163-170
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    • 2019
  • In spite of various advantages, steel fiber reinforced concrete is still limited in its use due to the insufficient research results on the structural performance and design criteria. This study evaluated the long-term behavior of the steel fiber reinforced concrete slabs by long-term loading experiments based on the short-term load bearing capacity of steel fiber reinforced concrete slabs obtained from previous studies. In this study, long-term loading experiments were carried out on Total four 2-span continuous slab specimens were tested for examining the long-term behavior of steel fiber reinforced concrete members. Long-term behavior characteristics of members were evaluated by measuring the long-term deflection, drying shrinkage, the number and width of cracks. Experimental results showed that the instant deflection of the steel fiber reinforced concrete slab is about 50% of the normal reinforced concrete slab. And, it was analyzed that the long-term deflection of the specimen using steel fiber reinforced concrete was about 10~20% lower than that of normal concrete by the long-term deflection over 100 days. In addition, the slab specimen using steel fiber reinforced concrete was evaluated to have just 70% of the number and width of cracks compared with normal concrete specimens.

Effect of Volume Fraction and Length of Fiber on the Mechanical Properties of Fiber Reinforced Concrete (섬유보강 콘크리트의 역학적 특성에 대한 섬유 체적비와 길이의 영향)

  • Yang, Keun-Hyeok;O, Seung-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.1
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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.

Strengthening Efficiency of Ring Type Steel Fibers in Concrete Panels (콘크리트 패널 내 원형 강섬유의 보강 효율성)

  • 조원택;이차돈;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.327-332
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    • 2001
  • It is generally observed that steel fiber reinforced concrete with traditional straight steel fibers overcomes brittle nature of plain concrete by failure mechanisms by fiber pull-out rather than fiber rupture resulting from fiber yielding or concrete fracture at failured surface. Ring type steel fibers in concrete which is confined in concrete matrix and has better orientation, thus, lead to fiber yielding and concrete fracture as well as increase of flexural behavior of concrete more efficiently, Comparative experimental study is performed in order to measure the relative efficiencies of steel fiber reinforced concrete reinforced with two different fibers. It is found that better toughness is obtained from the ring type steel fiber reinforced concrete than from straight steel fiber reinforced concrete under flexural loading.

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Mechanical Behavior of Steel Fiber Reinforced Polymer-impregnated Concrete (강섬유보강 폴리머침투콘크리트의 기계적 성질에 관한 연구)

  • 변근주;송영철;정해성;정기영
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.156-161
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    • 1993
  • This paper is to develop steel fiber reinforced polymer-impregnated concrete(SFPIC) by impregnation polymer impregnate into hardened steel fiber reinforced concrete(SFRC). Steel fiber induces ductile behavior and polymer impregnant increase compressive strength. Steel fiber reinforced polymer-impregnated concrete specimens are prepared with fiber contents of 0.0, 1.5, 2.0, 2.5% and tested to obtain uni-axial and bi-axial compression strengths, tensile strength and flexural strength. The strength and mechanical properties of normal concrete, SFRC, SFPIC are compared.

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Direct Tensile Behavior of Steel.Fiber Reinforced Concrete (강섬유콘크리트의 직접인장 거동 특성)

  • 이신호;고재군
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.29 no.4
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    • pp.124-131
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    • 1987
  • The aims of this study was to determine the mechanical properties of steel-fiber reinforced concrete under direct tensile loading, and also to insestigate the mechanism fiber reinforcement in order to improve the possible applications of steel-fiber reinforced concrete. In this study the major variables of experimental investigation were fiber conntents, and the lengths and diameters of fibers. The major results obtained are summarized as follows : 1. The strength, elastic modulus and energy absorption capability of steel-fiber reinforced concrete under direct tensile loading were improved as increasing of fiber contents. 2. The direct tensile strength of steel-fiber reinforced concrete was not influenced by the lengths of fiber, but was decreased as increasing of fiber diameters. 3. The direct tensile strength of steel-fiber reinforced concrete was not influenced by the fiber aspect-ratio, but this was because the fiber contents were below the critical value of fiber content. 4. The correlation of direct tensile strength and combined parameter, Vf l/d, was not good. 5. Mutiple cracking and post-crack resistance were investigated at stress-strain curves in direct tensile test. 6. The effect of fiber reinforcement can be influenced by fiber orientation and the bond strength between fiber and matrix. 7. The improvement of mechanical properties of steel-fiber reinforced concrete under direct tensile loading can be theoretically explained by the concept of composite materials.

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Interfacial bond properties and comparison of various interfacial bond stress calculation methods of steel and steel fiber reinforced concrete

  • Wu, Kai;Zheng, Huiming;Lin, Junfu;Li, Hui;Zhao, Jixiang
    • Computers and Concrete
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    • v.26 no.6
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    • pp.515-531
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    • 2020
  • Due to the construction difficulties of steel reinforced concrete (SRC), a new composite structure of steel and steel fiber reinforced concrete (SSFRC) is proposed for solving construction problems of SRC. This paper aims to investigate the bond properties and composition of interfacial bond stress between steel and steel fiber reinforced concrete. Considering the design parameters of section type, steel fiber ratio, interface embedded length and concrete cover thickness, a total of 36 specimens were fabricated. The bond properties of specimens were studied, and three different methods of calculating interfacial bond stress were analyzed. The results show: relative slip first occurs at the free end; Bearing capacity of specimens increases with the increase of interface embedded length. While the larger interface embedded length is, the smaller the average bond strength is. The average bond strength increases with the increase of concrete cover thickness and steel fiber ratio. And calculation method 3 proposed in this paper can not only reasonably explain the hardening stage after the loading end curve yielding, but also can be applied to steel reinforced high-strength concrete (SRHC) and steel reinforced recycled coarse aggregate concrete (SRRAC).

Tests on fiber reinforced concrete filled steel tubular columns

  • Gopal, S. Ramana;Devadas Manoharan, P.
    • Steel and Composite Structures
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    • v.4 no.1
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    • pp.37-48
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    • 2004
  • This paper deals with the strength and deformation of both short and slender concrete filled steel tubular columns under the combined actions of axial compression and bending moment. Sixteen specimens were tested to investigate the effect of fiber reinforced concrete on the ultimate strength and behavior of the composite column. The primary test parameters were load eccentricity and column slenderness. Companion tests were also undertaken on eight numbers of similar empty steel tubes to highlight the synergistic effects of composite column. The test results demonstrate the influence of fiber reinforced concrete on the strength and behavior of concrete filled steel tubular columns.

Improvement and Evaluation of Structural Performance of Steel Fiber Reinforced Concrete Beams Using Early Age Concrete (초기재령 강섬유보강 철근콘크리트 보의 구조성능 평가 및 개선)

  • Ha, Gee-Joo;Shin, Jong-Hack;Kwak, Yoon-Keun;Kwon, Chil-Sung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.3
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    • pp.129-137
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    • 1999
  • Reinforced concrete structures using early age concrete were result in the degradation of structural performance due to crack, overload, unexpected vibration and impact load. It demands urgently that reinforced concrete structure using early age concrete should be improved the serviceability and structural performance with the application of new fiber materials. Therefore specimens, designed by the test varibles, such as with or without stirrup and percent of steel fiber incorporated, were constructed and tested to evaluate and develop the structural performance of reinforced steel fiber concrete beam. Based on the test results reported in this study, the following conclusions are made. Specimens, designed by the over 0.75% of steel fiber incorporated, were showed the ductile behavior and failed slowly with flexure and flexure-shear. Comparing with the load-displacement relationship of specimen BSS, designed by the recommendations of the Ministry of Construction and Transportation, reinforced steel fiber concrete beam using early age concrete, over 0.75% of steel fiber incorporated, gets enough load carrying capacity and ductility. Increasing the percent of steel fiber incorporated(0.25~2.0%), the ultimate shear stress of each specimen were increased 12~40% than that of control specimen SSS.

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Slump and Mechanical Properties of Hybrid Steel-PVA Fiber Reinforced Concrete (강섬유와 PVA 섬유로 하이브리드 보강된 콘크리트의 슬럼프 및 역학적 특성)

  • Yang, Keun-Hyeok
    • Journal of the Korea Concrete Institute
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    • v.22 no.5
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    • pp.651-658
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    • 2010
  • Sixteen concrete mixes reinforced with hybrid steel-polybinyl alcohol (PVA) fibers and a control concrete mix with no fiber were tested in order to examine the effect of the micro and macro fibers on the slump and different mechanical properties of concrete. Main variables investigated were length and volume fraction of steel and PVA fibers. The measured mechanical properties of hybrid fiber reinforced concrete were analyzed using the fiber reinforcing index and compared with those recorded from monolithic steel or PVA fiber reinforced concrete. The initial slump of hybrid fiber reinforced concrete decreased with the increase of the aspect ratio and the volume fraction of fibers. In addition, splitting tensile strength, modui of rupture and elasticity, and flexural toughness index of concrete increased with the increase of the fiber reinforcement index. Modulus of rupture and flexural toughness index of hybrid fiber reinforced concrete were higher than those of monolithic fiber reinforced concrete, though the total volume fraction of hybrid fibers was lower than that of monolithic fiber. For enhancing the flexural toughness index of hybrid fiber reinforced concrete, using the steel fiber of 60 mm length was more effective than using the steel fibers combined with 60 mm and 30 mm lengths.

Flexural Strength of Steel Fiber Reinforced Concrete Beams (강섬유보강 콘크리트보의 휨강도에 관한 연구)

  • 김우석;백승민;곽윤근
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.695-700
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    • 2001
  • The objective of this study is to evaluate the flexure strength of steel fiber reinforced concrete beams and the effect of the adding steel fiber to flexural strength, and is to compare the proposed equation with the previous equation for predicting the flexural strength of fiber reinforced concrete beams. Based on earlier published studies and tests, predictive equation is proposed for evaluating the flexural strength of steel fiber reinforced concrete beams. The proposed equation gave good prediction for the flexural strength of the tested beams.

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