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Micro-CT 활용 콘크리트 내 철근 早식 정량을 위한 실험적 연구
장인동 ( Jang In-dong ),이종구 ( Yi Chong-ku ) 한국건축시공학회 2019 한국건축시공학회 학술발표대회 논문집 Vol.19 No.1
Corrosion of rebars in reinforced concrete structures is a major factor that shortens the life of the structure. As corrosion progresses, the adhesion between the concrete tissues and the rebar decreases and the cracks in the concrete due to the expansion of the oxide intensify. Although it is necessary to measure corrosion behavior of rebars inside the concrete to measure degradation of structures due to rebar corrosion, no studies have been conducted to measure corrosion of rebars in In-situ state. In this study, corrosion of rebars in reinforced concrete specimens was attempted to be quantified using micro-computer tomography. Since corrosion of concrete takes several months per 10mm of cover, accelerated corrosion techniques were applied. Accelerated corrosion on the specimen was conducted by applying a 10 V magnetic field to the buried rebar and external electrodes with the specimen submerged in a 10% calcium chloride solution. The experiment found that within two weeks, more than 40% of rebar reduction occurred, and the cracks in the radial cracks occurred through the concrete structure, leading to the transfer of the oxide produced through the cracks to the surface of the specimen.
서스펜션 민감도 해석을 이용한 SRS 성능 개선 방안 연구
장영진(Youngjin Jang),김국태(Guktae Kim),신상하(Sangha Shin),장진희(Jinhee Jang),김인동(Indong Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
This paper describes the sensitivity study and case study for improving the Smooth Road Shake (SRS) performance. Smooth Road Shake performance is one of the top quality concerns that directly affect vehicle sales. It is an important factor to ensure vehicle ride performance. So, the SRS design targets need to be defined and the proposed design needs to be assessed very early in the vehicle development phase. The SRS is composed of the steering wheel and floor panel vibrations caused by tire imbalance mass. This study focuses on the steering wheel torsional vibration resulting from the fore/aft walking mode of the corner caused by imbalance mass. We performed the fundamental dynamic simulation of SRS by using ADAMS solver based on Motionview with in-house templates. We showed the dominant factor for enhancing the SRS performance and we provided design recommendation.
장인동 ( Jang Indong ),김소현 ( Kim Sohyun ),송지훈 ( Song Jihun ),이종구 ( Yi Chongku ) 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.23 No.2
본 연구는 철근 콘크리트 내 강제 부식된 철근의 단조가력(Monotonic loading) 부착성능을 파악하고, 추후 해석모델 검증을 위한 데이터를 확보하기 위한 것이다. 이를 위해 이전 연도에 진행된 연구(철근 콘크리트의 가속 부식 실험 방법 정립 및 부식 특성 분석)를 바탕으로 제작된 철근 콘크리트 부재의 부식이 진행되었다. 철근의 직경, 철근 부식도, 콘크리트 압축 강도가 실험 변수로 지정되었고, 선행 연구를 바탕으로 자체 제작한 인발 시험기를 활용하여 실험 변수에 따른 철근의 콘크리트 인발 거동을 실험하였다.
이형 철근의 콘크리트 부착 모델 수립을 위한 Micro-CT 활용 단조가력 시험
장인동 ( Jang Indong ),조정현 ( Cho Junghyun ),이종구 ( Yi Chongku ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.2
In reinforced concrete adhesion studies, the demolition of the specimen is inevitably involved, and the studies conducted are limited to the macro load-displacement analysis. In order to establish an elaborate model for concrete bonding reinforced rebars, it is necessary to observe the rebar bonding behavior in the in-situ state. In this study, specially manufactured reinforcing bars, micro-UTM and μ-computer tomography (μCT) are used to observe reinforcing bars in the in-situ state. As a result of the monotonic pullout test of the processed reinforcing bar, maximum bond stress were shown to be 16.7MPa, which is slightly higher than the existing 10 to 12 MPa, and then the empty space inside the specimen in which the pullout test was conducted using μCT was confirmed. Through additional research, the fracture phenomenon of concrete excluding voids will be studied.
박테리아 펠렛을 자기치유 소재로 사용한 모르타르의 강도 및 치유성능
장인동(Indong Jang),손다솜(Dasom Son),류영웅(Young-ung Ryu),박우준(Woojun Park),이종구(Chongku Yi) 한국건설순환자원학회 2020 한국건설순환자원학회 논문집 Vol.8 No.1
본 연구에서는 메틸 셀룰로오스를 기반으로 제작한 박테리아 펠렛을 모르타르에 혼입하였으며, 펠렛 혼입에 따른 모르타르 내부 생존률과 강도, 정수위 투수실험에 의한 균열 치유율을 조사하였다. 펠렛은 복합 배양한 박테리아 포자 분말과 메틸셀룰로오스, PVA 영양소 2종과 물로 이루어져 있으며, 유압 프레스를 통해 압출되어 지름 2mm∼길이 3∼4mm의 형상을 갖는다. 셀룰로오스 펠렛은 중성 pH에서 팽창하여 박테리아와 영양소를 방출하고, 염기성 환경에서 반응하지 않는 성질을 띄어 시멘트 모르타르 내부 박테리아의 장기 생존률이 증대하는 효과가 있다. 또한 펠렛 혼입 모르타르는 정수위 투수실험을 통한 균열 자기치유 성능이 대조군 모르타르에 비해 현저히 상승하였다. 셀룰로오스 기반 펠렛은 새로운 종류의 박테리아 담체 시스템으로 추후 펠렛 개량 및 최적화로 자기치유 콘크리트 개발에 도움을 줄 것이다. In this study, cellulose-based bacterial pellets was used for the self-healing concrete manufacturing. The pellet is composed of complex cultured bacterial spore powder, methyl cellulose, two kinds of PVA nutrients and water, and is extruded through a hydraulic press to have a shape of 2mm in diameter to 3 to 4mm in length. Cellulose pellets expand at neutral pH, release bacteria and nutrients, and do not react in a basic environment, increasing the long-term survival rate of bacteria in cement mortar. In addition, pellet self-healing performance of pellet mortar was significantly higher than that of control mortar. Cellulose-based pellets are a new type of bacterial carrier system that will help develop self-healing concrete in the future by improving and optimizing pellets.