• Structural Engineering and Mechanics
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• 제53권6호
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• pp.1253-1269
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• 2015

The present paper investigates the post heating behavior of concrete beams reinforced with fiber reinforced polymer (FRP) bars, namely carbon fiber reinforced polymer (CFRP) bars and glass fiber reinforced polymer (GFRP) bars. Thirty rectangular concrete beams were prepared and cured for 28 days. Then, beams were either subjected (in duplicates) to elevated temperatures in the range (100 to $500^{\circ}C$) or left at room temperature before tested under four point loading for flexural response. Experimental results showed that beams, reinforced with CFRP and GFRP bars and subjected to temperatures below $300^{\circ}C$, showed better mechanical performance than that of corresponding ones with conventional reinforcing steel bars. The results also revealed that ultimate load capacity and stiffness pertaining to beams with FRP reinforcement decreased, yet their ultimate deflection and toughness increased with higher temperatures. All beams reinforced with FRP materials, except those post-heated to $500^{\circ}C$, failed by concrete crushing followed by tension failure of FRP bars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.527-533
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• 1997

The purpose of this study is to investigate the fatigue behavior of the reinforced concrete beams strengthened with steel plate and CFS(csrbon fiber sheet). In this study, fatigue loads of 60 to 80 percent of the ultimate strength are applied to the specimens. From the results of test the beams strengthened with steel plate show the flexural failure mode, while the specimens strengthened with CFS fail by separation between CFS and concrete surface. In case of the stress level of 70%, strength degradations of the beams with steel plate and CFS in normalized flexural rigidity at 5,000 cycles is 24 and is 24 and 28 percent respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.461-464
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• 2005

As the research on the development of the lightweight concrete block by the hydro-thermal synthetic reaction mixed with the calcareous material and bottom ash that is used less among siliceous material, we studied on the physical and chemical characteristics in the changes of hydro-thermal synthetic reaction of lightweight concrete block compounded with the PP fiber to increase flexural toughness and to prevent fragility failure. The results of the experiment are as follow. According to the increase of hydro-thermal synthetic reaction and the fiber content, compressive and flexural strength increased. Despite the changes of the hydro-thermal synthetic reaction time, tobermorite was produced on each of the specimens similarly. However, the phase of tobermorite was changed in accordance with the changes of time. Also, $CaCo_{3}$ appeared on the surface of the 9 hour hardened specimen.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.139-140
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• 2014

The purpose of this study in to evaluate relationship between mechanical properties of materials and fiber type by reinforced fiber with high-velocity impact fracture behavior of fiber reinforced concrete. As a result, for fracture behavior by high-velocity impact, it is considered that impact fracture behavior is not affected by static mechanical properties directly but affected by fiber type and density of the number of fiber. It is necessary to consider type, shape, mechanical properties and the number of fiber with flexural and tensile performance for the evaluation on impact resistance performance of fiber reinforced concrete.

• Steel and Composite Structures
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• 제4권2호
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• pp.113-132
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• 2004

Double skin composite element (DSCE) is a novel form of construction comprising two skins of profiled steel sheeting with an infill of concrete. DSCEs are thought to be applicable as shear or core walls in a building where they can resist in-plane loads. In this paper, the behaviour of DSCE subjected to combined bending and shear deformation is described. Small-scale model tests on DSCEs manufactured from micro-concrete and very thin sheeting were conducted to investigate the flexural and shear behaviour along with analytical analysis. The model tests provided information on the strength, stiffness, strain conditions and failure modes of DSCEs. Detailed development of analytical models for strength and stiffness and their performance validation by model tests are presented.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.107-112
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• 1991

The object of this study is to investigate material characteristics and flexural behavior of high strength concrete. Principal causes of variations of high compressive strength include the strength-producing capabilities of cement and silica hume. Compressive strength of 1200 kgf/$\textrm{cm}^2$ is introduced for identifying the effect of the variation of the size of porocity and alternative method of measurement, Acoustic Emition method, is applied to examine the phenominon of concrete failure. The main test variables in the beam element are tensile steel ratios, presence of shear reinforcement, and change of steel shape. The estimation of stress block in the flexural test of this element tends to support the present theory and may suggest a desirable shape of the stress block.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.473-476
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• 2004

Carbon Fiber Reinforced Polymer(CFRP) composites are widely applied to strengthen deteriorated concrete structures. This paper presents the experimental results of the performance of reinforced concrete(RC) beams strengthened with Near Surface Mounted T-shape CFRP. Simple beams with 3m span length were tested to investigate the effect of CFRP reinforcement shapes on the flexural behavior of strengthened RC beams. The test results were analyzed with the special emphasis on the failure mode and the maximum load.

• Computers and Concrete
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• 제4권1호
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• pp.19-32
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• 2007

This paper is concentrated on the behaviors of five different types of fiber reinforced concrete (FRC) in uniaxial tension and flexural impact. The complete stress-strain responses in tension were acquired through a systematic experimental program. It was found that the tensile peak strains of concrete with micro polyethylene (PEF) fiber are about 18-31% higher than that of matrix concrete, those for composite with macro polypropylene fiber is 40-83% higher than that of steel fiber reinforced concrete (SFRC). The fracture energy of composites with micro-fiber is 23-67% higher than that of matrix concrete; this for macro polypropylene fiber and steel fiber FRCs are about 150-210% and 270-320% larger than that of plain concrete respectively. Micro-fiber is more effective than macro-fiber for initial crack impact resistance; however, the failure impact resistance of macro-fiber is significantly larger than that of microfiber, especially macro-polypropylene-fiber.

• Steel and Composite Structures
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• 제8권5호
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• pp.423-438
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• 2008

This paper reports an experimental investigation of the behaviour of concrete-encased composite columns subjected to short-term axial load and biaxial bending. In the study, six square and four L-shaped cross section of both short and slender composite column specimens were constructed and tested to examine the load-deflection behaviour and to obtain load carrying capacities. The main variables in the tests were considered as eccentricity of applied axial load, concrete compressive strength, cross section, and slenderness effect. A theoretical procedure considering the nonlinear behaviour of the materials is proposed for determination of the behaviour of eccentrically loaded short and slender composite columns. Two approaches are taken into account to describe the flexural rigidity (EI) used in the analysis of slender composite columns. Observed failure mode and experimental and theoretical load-deflection behaviour of the specimens are presented in the paper. The composite column specimens and also some composite columns available in the literature have been analysed and found to be in good agreement with the test results.

• 한국구조물진단유지관리공학회 논문집
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• 제7권3호
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• pp.125-131
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• 2003

본 연구에서는 최근 구조물 보강을 위해 사용이 증가하고 있는 CFRP로 보강된 철근콘크리트 보의 휨거동 특성을 분석하였다. 실험변수로 보강길이와 폭, 철근비, 단부정착 여부 그리고 무보강 기준실험체의 예상 극한하중의 75%에 상응하는 사전하중 여부를 고려하였으며, 각각의 실험변수에 따른 영향을 분석하였다. 이를 위해, 총 20개의 철근콘크리트 보를 제작하고 실험을 수행하였으며, 실험변수에 따른 극한하중, 처짐, CFRP의 변형률 그리고 파괴모드의 변화 특성에 대해 연구하였다.