CFRP 그리드의 최적 인장 시험방법 제시 및 고온 노출에 따른 성능평가 = Optimized Tensile Test Method for Assessing the Performance of CFRP Grids under High-Temperature Exposure

국문 초록 (Abstract)

FRP 복합재료 중 CFRP(탄소 섬유 강화 플라스틱)는 현재 RC 구조물의 내부 및 외부 보강재로서 그리드 형태로 활용되고있다. 그러나 CFRP 그리드에 대한 성능평가 기준은 매우 미흡하여 FRP 보강근 기준을 사용하고 있다. 따라서 본 연구에서는 그리드가닥 수와 경계조건과 변수를 고려하여 CFRP 그리드의 인장 성능을 평가하기 위한 실험이 수행되었다. 가닥 수는 1, 2, 3가닥에 대한인장시험이 수행되었으며, 경계조건의 경우 모르타르, 에폭시, 에폭시 + 모르타르로 변수를 지정하였다. 인장시험을 통하여 최적 가닥수 및 최적 경계조건으로 개발한 시편을 토대로 고온 노출 시간에 따라 CFRP 그리드의 인장 성능 평가가 수행되었다. 온도는 130°C 로 유지되었으며, 5개의 시편을 각각 70분(Case 2), 100분(Case 3), 120분(Case 4), 150분(Case 5) 고온에 노출하여 비 고온 노출 시편과 비교하였다. 실험 결과, 비 고온 노출 시편과 비교하여 Case 5에서는 인장강도와 탄성계수가 각각 최대 51.32% 및 44.4% 감소한것으로 나타났다.

다국어 초록 (Multilingual Abstract)

Among fiber reinforced plastic (FRP) composites, carbon FRP (CFRP) is commonly used in the form of grids for both internal and external reinforcement in reinforced concrete structures. However, existing performance evaluation standards for CFRP grids are inadequate, necessitating the adoption of standards intended for FRP reinforcement bars. This study aims to address this gap by evaluating the tensile performance of CFRP grids by considering various variables, such as the number of grid strands and type of filling materials within the tubes. Tensile tests were carried out on CFRP grids comprising 1, 2, and 3 strands, and the filling materials tested included mortar, epoxy, and a combination of epoxy and mortar. Based on the results, which identified the optimal number of strands and filling materials, further tests were performed to assess the tensile performance of CFRP grids under varying high-temperature exposure durations. The temperature was consistently maintained at 130℃, with five specimens subjected to high temperatures for 70 min (Case 2), 100 min (Case 3), 120 min (Case 4), and 150 min (Case 5). These were compared with specimens that were not exposed to high temperatures (Case 1). The experimental results showed that, compared with specimens not exposed to high temperatures, the tensile strength and modulus of elasticity in Case 5 decreased by up to 51.32% and 44.4%, respectively.

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