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Title |
Feasibility of Using Cementitious Composite Sensors Including Fe-Modified Biochar?MWCNT for Monitoring Strain and Damage of Concrete Shear Walls
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Authors |
우진석(Jin-Seok Woo) ; 윤현도(Hyun-Do Yun) ; 김선우(Sun-Woo Kim) ; 박완신(Wan-Shin Park) ; 최원창(Won-Chang Choi) ; 서수연(Soo-Yeon Seo) |
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DOI |
https://doi.org/10.4334/JKCI.2025.37.3.381 |
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Keywords |
바이오차; 다중벽탄소나노튜브; 시멘트 기반 복합체; 변형감지센서; 지진 모니터링 biochar; multi-walled carbon nanotube (MWCNT); cement-based composite; strain-detecting sensor; seismic monitoring |
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Abstract |
This study developed a strain-detecting cementitious composite (FBMC) sensor by incorporating Fe-modified biochar and multi-walled carbon nanotubes (MWCNTs), and evaluated its applicability to real structures by embedding it in a concrete shear wall subjected to cyclic lateral loading. The sensing performance of the structural member’s deformation and damage level was quantitatively assessed through comparison with a commercial strain gauge. MWCNTs, added at 1 % by cement weight, were uniformly dispersed using ultrasonic treatment to form a conductive network within the matrix. Under cyclic compressive loading, the sensor’s performance was analyzed based on fractional change in resistance (FCR), response linearity, and gauge factor(GF). The FBMC sensor exhibited superior cyclic response stability and sensing precision (R²=0.913) compared to a sensor using only Fe-modified biochar (FBC). In the shear wall experiment, the FBMC sensor was embedded in the boundary region, and its FCR response was compared with vertical reinforcement strain, damage index (DI), and energy dissipation coefficient (η). The results showed that the sensor exhibited a peak FCR response at a drift ratio of 1.7 %, securing a wider damage-sensing range than the vertical reinforcement. Furthermore, strong correlations with DI and η confirmed the sensor’s quantitative ability to track structural damage progression. The FBMC sensor maintained high sensitivity and response stability under cyclic loading, demonstrating its suitability for real-time structural health monitoring. However, signal degradation due to disconnection of the conductive network after sensor cracking was observed.
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