• 한국산학기술학회논문지
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• 제8권2호
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• pp.348-353
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• 2007

본 연구에서는 중공형 섬유보강폴리머(Fiber Reinforced Polymer : FRP) 바닥판이 적용된 교량에 적합한 신축이음장치를 개발하고자 신축이음장치의 설계기준 및 특성을 분석하였다. 또한, 신축이음장치를 선정하는 기준이 되는 설계 신축량 산정법과 FRP바닥판 상세를 검토하여, 강콘크리트 거더 교량에 적용 가능한 FRP바닥판용 신축이음장치를 개발 제안하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.601-608
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• 2000

Steel fiber and Polymer are used widely for the reinforcement material of RC structures because of its excellence of durability, serviceability as well as mechanical properties. Polymer-Steel fibrous high strength concrete beam's input ratio are 1.0%. The shear span-to-depth ratio are 1.5, 2.8 and 3.6, compressive strength of specimens 320kg/㎠, 436kgf/㎠ and 520kgf/㎠ in 28 days. The static test was carried out to measure the ultimate load, the initial load of flexural crack and of diagonal crack, from which crack patte군 and fracture modes are earned. Also, stress-strain, load-strain and load-deflection are examined during the test cracks(shear crack, flexural crack, and diagonal tension crack), when the load values are sketched according to the growth of crack. Result are as follows; (1) The failure modes of the specimens increase in rigidity and durability in accordance with the increase of mixing steel fiber and polymer. (2) The load of initial crack was the same as the theory of shear-crack strength (3) Polymer-Steel fibrous high strength concrete beams have increased the deflection and strain at failure load, improving the brittleness of the high strength concrete. (4) In this result of study, an additional study need to make a need formular because the study is different from ACI formular and Zsutty formular.

• 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 2006년도 추계 학술발표회 논문집
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• pp.565-568
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• 2006

This study evaluates the physical mchanical properties, durability of porous concrete for pavement according to content of polymer and steel fiber to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of Korea National Housing Corporation as for every factor of mixture but in the case of the flexural strength, more than 0.6Vol.% of steel fiber satisfied the Japan Concrete Institute proposition values. The case when 0.6Vol.% of steel fiber and 10Wt.% of polymer are used at the same time shows that the loss rate of mass by Cantabro test became 36.7% better and freeze-thaw resistance became 33% better.

• Steel and Composite Structures
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• 제32권1호
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• pp.21-35
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• 2019

This study investigates the flexural behavior of steel-concrete composite beams strengthened with prestressed carbon fiber-reinforced polymer (CFRP) plates. An innovative mechanical anchorage system was developed. The components of the system can be easily assembled on site before applying a prestressing force, and removed from the structures after strengthening is completed. A total of seven steel-concrete composite specimens including four simply supported beams strengthened at the positive moment region and three continuous beams strengthened at the negative moment region were tested statically until failure. Experimental results showed that the use of prestressed CFRP plates enhanced the flexural capacity and reduced the mid-span deflection of the beams. Furthermore, by prestressing the CFRP laminates, the material was used more efficiently, and the crack resistance of the continuous composite specimens at the central support was significantly improved after strengthening. Overall, the anchorage system proved to be practical and feasible for the strengthening of steel-concrete composite beams. The theoretical analysis of ultimate bearing capacity is reported, and good agreement between analytical values and experimental results is achieved.

• 콘크리트학회논문집
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• 제25권3호
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• pp.313-320
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• 2013

이 연구에서는 환경을 고려한 고성능 보수 보강재료 개발을 위하여 섬유를 보강한 폴리머 시멘트 모르타르의 특성을 연구하였다. 친환경 수지인 UM 수지를 일반 시멘트 모르타르와 일정 비율로 혼합하였다. 강도 증진의 영향을 확인하기 위해서 PVA 섬유, 강섬유 그리고 PVA섬유와 강섬유를 일정한 비율로 혼합한 하이브리드 섬유를 일정한 비율로 첨가하였다. 강도특성을 파악하기 위하여 섬유를 보강한 폴리머 시멘트 모르타르에 대하여 압축강도, 쪼갬 인장강도, 휨강도 실험을 수행하였다. 내구성을 파악하기 위하여 폴리머 시멘트 모르타르에 대하여 흡수율 실험, 내약품성 실험을 수행하였다. 실험 결과 UM 수지 폴리머 시멘트 모르타르는 내구성능이 개선되었고, 이러한 폴리머 시멘트 모르타르에 섬유를 보강하면 콘크리트 및 모르타르의 취약점인 인장강도와 휨강도가 증가하였다. 향후 외부 노출된 콘크리트 구조물의 내구성 향상을 위한 보수보강재료로 사용성을 확인하였다.

• 콘크리트학회논문집
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• 제19권6호
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• pp.727-734
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• 2007

철근과 fiber-reinforced polymer (FRP)의 물리적, 역학적 특성의 차이 및 슬래브 상부 보강재의 기둥 인접부 집중 배근, 그리고 기둥 인접부 슬래브에 강섬유 콘크리트 (SFRC)의 타설 등에 따른 2방향 슬래브의 펀칭 전단 거동에 대한 효과를 평가하였다. 펀칭 전단강도, 강성, 연성, 변형률 분포 그리고 균열 제어 성능 등을 파악하였다. 실험 결과 기둥 인접부의 슬래브에 집중 배근을 하거나 SFRC를 타설하는 것은 glass fiber-reinforced polymer (GFRP) 바로 보강된 슬래브의 펀칭 전단 거동을 향상시켰다. 기둥 인접 구역에 집중 배근된 슬래브의 실험 결과를 다양한 설계기준과 타 연구자에 의해 제안된 예측식과 비교하였으며, 집중 배근으로 인한 이점을 예측식에 반영할 수 있도록 집중 배근된 슬래브의 철근비를 산정하는 합리적인 방법도 제안하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.114-117
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• 2006

Concrete beams reinforced with fiber reinforced polymer (FRP) bars exhibit large deflection and crack width as compared to concrete beams reinforced steel due to modulus of elasticity of FRP bars. Current design code for prediction and crack width developed in concrete structures reinforced with steel bars may not be used for concrete beams reinforced with FRP bars. Thus a number of researcher have attempted to propose modifications to the ACI 318 empirical equation for estimating the effective moment of inertia of reinforced concrete beams. Others used numerical method to calculate the deflection. The purpose of this paper is to evaluation of methods of ACI 440.1 R-01, ISIS Canada design manual, and others for predicting deflection for glass fiber reinforced polymer reinforced concrete beams.

• 한국공간구조학회논문집
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• 제7권3호
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• pp.141-151
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• 2007

The appearance of many Glass Fiber Reinforced Plastic (GFRP) constructions look like ordinary steel construction, because GFRP has been imitated by the same way with the traditional steel's cross section as well as connection system. In terms of detachable connection, there was not enough appropriate option of GFRP connection, such as a traditional bolt connection for steel and wood structures. Most of all, from material characteristic of GFRP related to the deficient ductility, the shearstress principle of GFRP s not proper for the material property, which causes ineffective and not economic application of material. With this research problem, the innovative and detachable onnection system, which is more considered with appropriate material characteristic for FRP, is developed. Not only short time but also long time research with various connection variations is carried out.

• 콘크리트학회논문집
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• 제25권5호
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• pp.573-581
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• 2013

이 논문은 강섬유보강콘크리트와 GFRP (glass fiber reinforced polymer)사이의 부착 특성을 조사하기 위한 실험적 연구를 수행하였다. 실험 주요 변수로는 보강근 지름, 섬유혼입량, 피복두께 및 콘크리트의 압축강도를 설정하였다. 부착파괴는 주로 콘크리트 피복에서의 쪼갬으로 인하여 유발되며, 이러한 콘크리트의 쪼갬파괴는 보강근과 콘크리트 사이의 변형 차이로 유발되는 인장력때문에 발생한다. 따라서, 보강근과 콘크리트 사이의 부착파괴를 방지하기 위하여, 콘크리트 피복부위의 인장강도를 향상시켜야 한다. 실험결과를 살펴보면, 섬유혼입량 증가는 부착강도를 크게 향상시키고 있으며, 피복두께는 최종 파괴모드를 변화시킴을 확인할 수 있었다. 보강근의 지름 또한 최종 파괴모드를 변화시킴을 확인할 수 있었다. 일반적으로 보강근의 지름은 부착특성에 영향을 미치는 것으로 알려져 있으나, 섬유혼입량은 부착특성에 큰 영향이 없는 것으로 알려져 있다. 콘크리트 압축강도의 증가는 보강근과 콘크리트 사이의 부착강도를 증가시켰으며, 이는 압축강도의 증가가 직접적으로 인장강도의 증가를 유발하기 때문이라고 판단된다.