• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
• /
• pp.323-326
• /
• 2005

Uniaxial tension test of Glass Fiber Reinforced Polymer (GFRP) bar reinforced concrete prisms was performed. The objective was to investigate the adequate cover thickness of the GFRP rebars. The tension stiffening effect of GFRP bar reinforced concrete was also studied. The test variables included rebar types (conventional steel rebar and two different GFRP rebars) and cover thicknesses (five different cover thicknesses ranging between 1-3db). Normal strength concrete was used. Cracking patterns on concrete surface and cracking loads were careful1y observed during the direct tensile test. The test results indicated that the adequate cover thickness of the GFRP rebars may even be larger than that of the steel rebars and that the cover thickness of 2db commonly specified for the GFRP rebars may not be large enough. The tension stiffening effect of the GFRP rebars was also quantified and documented from the test results.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.124-127
• /
• 2004

This study is to investigate the bond characteristics of glass fiber reinforced polymer(GFRP) reinforcing bars in concrete by pullout test experimentally. Three different types of GFRP bars with different surface deformations were considered in this study. Also, standard deformed steel reinforcing bar with or without epoxy-coating were included for the comparisons of bond strength. All test procedures including specimens preparation, test apparatus and measuring devices were made according to the recommendation of CSA(Canadian Standards Association) Standard S806-02. From the test results, it was found that small surface indentations contributed to increase the bond strength of GFRP bar significantly. Based on the limited test results till now, the bond strength of GFRP bar with sand-coated deformation commercially available in foreign market is around $80\%$ of that of steel deformed bars.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
• /
• pp.273-276
• /
• 2006

Airborne chlorides is moved to inland by sea wind and attach to the surface of concrete then penetrated into concrete. In addition, concrete structures are greatly affected by salt attack primarily due to airborne chlorides like it can be seen through the corrosion of rebar. Therefore, it is important to review the relationship among airborne, surface and penetrated chlorides. In this study, airborne, surface and penetrated chlorides were examined in terms of surface roughness of concrete. The results showed that penetrated and surface chlorides have close relationship with surface roughness of concrete.

• 대한토목학회논문집
• /
• 제26권4A호
• /
• pp.775-785
• /
• 2006

본 논문은 우수한 부착성능과 더불어 단순한 공정으로 생산이 가능한 GFRP 보강근의 표면성형 기법을 제시하였다. 논문에는 제안하고자하는 표면성형기법에 대한 내용과 개발된 보강근의 콘크리트 부착성능에 대하여 언급하였다. 본 논문에서 제안하는 표면성형공법은 에폭시레진에 초단섬유인 milled glass fibers를 혼입하여 GFRP 보강근의 외부에 프레스 성형하는 공법이다. milled fibers의 적적한 혼합비를 결정하기 위하여 다양한 혼입비로 제작된 경화된 에폭시 시편의 압축강도실험과 다양한 혼입비의 표면형상을 갖는 부착시험편의 pull-out 실험이 수행되었다. 실험결과, 정적하중하에서 뿐 아니라 환경하중 재하상태에서도 milled fibers의 혼입량이 증가할수록 콘크리트와의 부착성능이 증진됨을 확인됨으로써 본 공법의 효용성을 검증하였다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 가을 학술논문 발표대회
• /
• pp.37-38
• /
• 2022

During the past decades, the corrosion of the steel rebar embedded in concrete structure surrounding marine environment is actually problematic and required the suitable preventive method. An eco-friendly corrosion inhibitor mix is investigated to stifle the active corrosion in comparison with other commercial corrosion inhibitors. The hybrid inhibitor enhances the corrosion resistance and the workability of concrete. However, it reduces the compressive strength slightly after 28-day-age. The electrochemical studies and mechanical studies are pointed out the corrosion resistance property, corrosion kinetics, and the mechanical properties of all concrete samples. H-3 is the optimum dose of hybrid inhbitor that meets the demand of both electrochemical property and mechanical property. It performs the noble features due to the formation of optimum amount of P-Zwitterions-(Cl)-Fe complex onto the steel rebar surface.

• 한국구조물진단유지관리공학회 논문집
• /
• 제16권2호
• /
• pp.40-48
• /
• 2012

콘크리트내의 철근의 부식은 열화와 콘크리트 구조물의 조기파괴의 주된 원인이 된다. 본 연구에서는 비파괴 기법 중 전자기적 열유도방법과 적외선 열화상기법을 이용한 철근부식평가가 시도되었는데, 부식 또는 비부식된 철근의 열특성 차이를 이용한 것이다. 본 논문은 이러한 개념을 배경으로 수행한 실험적 연구이며, 유도전류를 통해 콘크리트 표면으로부터 내부 철근을 가열하고 외부의 적외선 카메라를 이용하여 표면의 온도변화를 관측한다. 피복두께가 다른 콘크리트 시편은 앞면과 배면의 피복두께를 동일하게 제조하여 앞면에서 가열과 배면에서의 온도측정을 동시에 할 수 있도록 고안되었다. IC (Impressed Current) 방법을 통하여, 철근 부식을 촉진하였으며, 적외선 화상을 통하여 온도가열과 냉각을 전 시험과정에 걸쳐 측정하였다. 본 실험을 통하여 부식/비부식 철근의 뚜렷한 온도변화를 확인하였으며, 부식된 시편에서 빠른 온도증가속도 및 냉각속도를 평가하였다. 본 연구는 콘크리트 매립철근의 비파괴적인 부식탐지의 가능성을 보여주고 있다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.112-113
• /
• 2021

Phosphate based inhibitor is playing a decisive role in inhibiting the corrosion of steel rebar in chloride condition. We have used different amount of ammonium phosphate monobasic (APMB) as corrosion inhibitor in mortar with different amount of chloride ions. The compressive strength, flexural strength, open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization resistance (PPR), scanning electron microscopy (SEM) and Raman spectroscopy were performed to access the effect of inhibitor on corrosion resistance. As the amount of inhibitor is increased, the compressive strength increased. The electrochemical results show that as the amount of inhibitor and chloride ions are increased, the total impedance and corrosion resistance of steel rebar increased attributed to the formation of the stable oxide films onto the steel rebar surface. It is suggested that APMB can work in high concentration of chloride ions present in concrete where phosphate ion helps in formation of stable and protective phosphate based oxide film.

• 한국건축시공학회지
• /
• 제19권6호
• /
• pp.511-520
• /
• 2019

혼화재 혼입에 따른 콘크리트의 철근부식 임계염화물량의 변화를 실험적으로 평가하였다. 콘크리트 배합조건은 OPC 100%, OPC 70% + GGBFS 30%, OPC 40% + GGBFS 60%, OPC 40% + GGBFS 40% + FA 20% 로 구분하여 4가지 배합의 철근 콘크리트 시험체를 제작하였다. 시험체에 NaCl 수용액을 공급하며, 매립된 철근의 자연전위를 모니터링 하였다. 부식이 발생한 것으로 판단된 시험체는 NaCl 수용액 공급면으로부터 5mm간격으로 절단하여 염소이온량 프로파일을 실시하였다. 콘크리트에 매립된 철근의 부식 개시시기는 시멘트를 혼화재로 치환하여 사용하는 경우 지연되는 것을 확인하였다. 하지만 콘크리트에 매립된 철근의 부식임계염화물량은 혼화재 혼입율 증가에 따라 감소하여, OPC 1.46kg/㎥, S30 0.98kg/㎥, TBC 0.74kg/㎥, S60 0.71kg/㎥ 순으로 높게 나타났다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 봄 학술논문 발표대회
• /
• pp.43-44
• /
• 2022

In this study, the optimum amount of chloride ions is used to collaborate with hybrid corrosion inhibitor for carbon steel rebar treatment in simulated pore concrete (SCP) solution is discovered. The corrosion inhibition performance of hybrid inhibitors is carried on by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP). The highest corrosion inhibition resistance is found in case of LP-C2 after 240 h exposure. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate well with electrochemical studies. Anodic type inhibition action was confirmed by potentiodynamic polarization study.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 가을 학술논문 발표대회
• /
• pp.65-66
• /
• 2021

In this study, the optimum amount of hybrid inhibitors i.e. L-Arginine (LA) and sodium phosphate tribasic dodecahydrate (SP), applied for carbon steel rebar in simulated pore concrete (SCP) solution contaminated with 3.5 wt.% NaCl, was discovered. The corrosion inhibition performance of hybrid inhibitors was investigated by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization. The highest corrosion inhibition efficiency was found as 99.52% corresponding to 2% LA and 0.25% SP after 210 h exposure. Anodic type inhibition action was confirmed by potentiodynamic polarization study. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate with electrochemical studies.