CFRP 판으로 전단 보강된 이후 동결융해에 노출된 철근콘크리트 보의 거동 및 음향방출 특성 (Behavior and Acoustic Emission (AE) Activities Characteristics of Reinforced Concrete Beams Strengthened in Shear with Carbon Fiber-Reinforced Polymer(CFRP) Plate Exposed to Freezing and Thawing Cycle)

서지정보

· 발행기관 : 대한건축학회
· 수록지 정보 : 대한건축학회논문집 구조계 / 24권 / 9호 / 3 ~ 12페이지
· 저자명 : 윤현도, 김선우, 이영오, 전수만, 서수연, 최기봉

초록

External plating of reinforced concrete (RC) structures with carbon fiber-reinforced polymer (CFRP) plate, sheets, or both, is
now a widely recognized as repair and retrofit technique. CFRP sheets and plates are being used to strengthen outside concrete
structures. The CFRP reinforcements are bonded to beams and slabs using structural adhesives. Adhesive strength can be
affected by environmental exposure. During freezing-and-thawing cycling, temperature-induced stresses in the adhesive layer, due
to differential thermal expansion between the CFRP and the substrate concrete, may lead to bond damage and contribute to or
cause premature CFRP composite separation. This paper presents the results of experimental program undertaken to investigate
the effects of freeze-thaw cycling (from -18 to 4℃) on the behavior and failure characteristics of RC beams strengthened in
shear with CFRP plate using acoustic emission (AE) technique. The beams were plated with CFRP plate (S system, thickness of
1.2 mm, tensile strength of 2,800 MPa) then were subjected to between 0 and 400 freezing-and-thawing cycles. Based on the
results presented, freezing-and-thawing cycling between 0 and 120 cycles does not appear to significantly affect the overall load
deflection behavior, the crack development, and strain distributions of RC beams strengthened in shear with CFRP plate. But
CFRP-strengthened concrete beams exposed to more than 240 freezing-and-thawing cycles exhibited 10% reduction in strength
compared to CFRP-strengthened RC beam without being exposed to freezing-and-thawing. The AE-b value derived from the
frequency-amplitude distribution of AE signals, was compared with the development of fracture process of CFRP-strengthened
RC beams.

영어초록

External plating of reinforced concrete (RC) structures with carbon fiber-reinforced polymer (CFRP) plate, sheets, or both, is
now a widely recognized as repair and retrofit technique. CFRP sheets and plates are being used to strengthen outside concrete
structures. The CFRP reinforcements are bonded to beams and slabs using structural adhesives. Adhesive strength can be
affected by environmental exposure. During freezing-and-thawing cycling, temperature-induced stresses in the adhesive layer, due
to differential thermal expansion between the CFRP and the substrate concrete, may lead to bond damage and contribute to or
cause premature CFRP composite separation. This paper presents the results of experimental program undertaken to investigate
the effects of freeze-thaw cycling (from -18 to 4℃) on the behavior and failure characteristics of RC beams strengthened in
shear with CFRP plate using acoustic emission (AE) technique. The beams were plated with CFRP plate (S system, thickness of
1.2 mm, tensile strength of 2,800 MPa) then were subjected to between 0 and 400 freezing-and-thawing cycles. Based on the
results presented, freezing-and-thawing cycling between 0 and 120 cycles does not appear to significantly affect the overall load
deflection behavior, the crack development, and strain distributions of RC beams strengthened in shear with CFRP plate. But
CFRP-strengthened concrete beams exposed to more than 240 freezing-and-thawing cycles exhibited 10% reduction in strength
compared to CFRP-strengthened RC beam without being exposed to freezing-and-thawing. The AE-b value derived from the
frequency-amplitude distribution of AE signals, was compared with the development of fracture process of CFRP-strengthened
RC beams.

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