• 제목/요약/키워드: surface chloride concentration

검색결과 244건 처리시간 0.026초

비색판별법을 이용한 콘크리트의 표면염화물량 산정 (A Study for the Calculation of the Surface Chloride on the concrete by using Colorimetric method)

  • 이진우;이문환;서치호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.815-820
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    • 2001
  • This study is to set a new standard for using of the colorimetric method through grasping the character of the colorimetric method, and measuring the chloride concentration at the place of the change of color. Also, to predict chloride concentration around rebar and time reaching limit chloride concentration through measuring the chloride concentration of concrete surface by the colorimetric method and this study presents the new program of concrete degradation and diagnosis of the durability by salt damage. First the use of the colorimetric method was examinated, second the chloride concentration through slicing concrete submerged in artificial seawater for 6 months was measured. And the chloride concentration at the place of the change of color was calculated by using colorimetric method. Finally, the cloride concentration of the concrete surface was calculated.

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염화물의 농도가 전기아연도금에 미치는 영향 (Effects of Chloride Concentration on Zinc Electroplating)

  • 김재민;이정훈;김용환;김영하;홍문희;정훤우;정원섭
    • 한국표면공학회지
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    • 제43권2호
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    • pp.51-56
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    • 2010
  • The zinc electroplating with respect to the chloride concentration was investigated by X-ray diffraction(XRD), scanning electron microscope (SEM), and cathodic polarization measurement. The cathodic overpotential during electroplating was first decreased and then increased with increase of chloride concentration in electrolyte. The decreased cathodic overpotential leads to preferred orientation of (002) plane, high current efficiency and satisfactory zinc deposits. The increased cathodic overpotential causes random orientation, low current efficiency and edge burning. The cathodic overpotential was affected by chloride concentration in electrolyte, not by the kind of chloride, such as NaCl and KCl. An optimized chloride concentration was 3 M for zinc electroplating. Also, it is considered that NaCl can be a alternation for KCl as a main salt of zinc electroplating bath.

Probabilistic evaluation of chloride ingress process in concrete structures considering environmental characteristics

  • Taisen, Zhao;Yi, Zhang;Kefei, Li;Junjie, Wang
    • Structural Engineering and Mechanics
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    • 제84권6호
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    • pp.831-849
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    • 2022
  • One of the most prevalent causes of reinforced concrete (RC) structural deterioration is chloride-induced corrosion. This paper aims to provide a comprehensive insight into the environmental effect of RC's chloride ingress process. The first step is to investigate how relative humidity, temperature, and wind influence chloride ingress into concrete. The probability of initiation time of chloride-induced corrosion is predicted using a probabilistic model that considers these aspects. Parametric analysis is conducted on several factors impacting the corrosion process, including the depth of concrete cover, surface chloride concentration, relative humidity, and temperature to expose environmental features. According to the findings, environmental factors such as surface chloride concentration, relative humidity and temperature substantially impact on the time to corrosion initiation. The long- and short-distance impacts are also examined. The meteorological data from the National Meteorological Center of China are collected and used to analyze the environmental characteristics of the chloride ingress issue for structures along China's coastline. Finally, various recommendations are made for improving durability design against chloride attacks.

제설제 살포에 따른 콘크리트 포장의 염화물 침투특성 (Characteristics of Chloride Penetration due to Sprinkle of the Deicing Salt on the Concrete Pavement)

  • 박진호;김명유;양은익;이성태;박해균
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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    • pp.475-478
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    • 2005
  • Deicing salt has been generally used for traffic safety in winter, and the amount is increasing every year. However, deicing salt may induce the decrease of bond strength, surface scaling, and environmental pollution, etc. the purpose of this paper is to suggest the fundamental data on safety and durability for concrete structures through the estimation of chloride concentration profile and chloride diffusion coefficient. According to the test results, the critical chloride concentration($0.9\~1.2kg/m^3$)was measured at depth $23\~30mm$, and the limit chloride concentration($0.3kg/m^3$)was reached to depth 40mm. Also the surface chloride amount indicates 3.45kg per concrete unit weight, and the results showed the possibility of corrosion by deicing salt penetration.

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염화물을 함유한 제설제가 콘크리트의 열 특성과 미끄럼저항성에 미치는 영향에 관한 연구 (Effect of Chloride-containing Deicer on the Thermal Charateristics and Skid Resistance of Concrete)

  • 이병덕;윤병성
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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    • pp.509-512
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    • 2004
  • This research is targeting that estimate the effect on cement concrete pavement with type of chloride deicers. In order to this study objective, when chloride deicers were spread on road surface, thermal characteristics test was conducted. Also, skid resistance test according to types and concentration of chloride deicier, road surface conditions were investigated. As a test results, thermal characteristics with kind of chloride deicier could know that sodium chloride(NaCl) is exothermic reactive material, calcium chloride$(CaCl_2)$ is endothermic reactive material. And, in case of mixed salt of the calcium and sodium chloride, it could know that can change to the exothermic or endothermic reaction according to dosage ratios. Skid value by British Pendulum Tester(BPT) has shown that it is seldom difference between the types($CaCl_2$, NaCl, mixed salt) and solution concentrations(0.5, 0.8, 1.0, 4.0, $10\%$) of chloride deicier comparing with tap water except mixed salt($10\%$ solution concentration).

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산성비 환경을 모사한 수용액에서 염화물 농도에 따른 전기자동차 배터리 하우징용 재료의 전기화학적 특성 연구 (Investigation on Electrochemical Characteristics of Battery Housing Material for Electric Vehicles in Solution Simulating an Acid Rain Environment with Chloride Concentrations)

  • 신동호;김성종
    • Corrosion Science and Technology
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    • 제21권2호
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    • pp.147-157
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    • 2022
  • Electrochemical characteristics and damage behavior of 6061-T6 aluminum alloy used as a battery housing material for electric vehicles were investigated in solution simulating the acid rain environment with chloride concentrations. Potentiodynamic polarization test was performed to analyze electrochemical characteristics. Damage behavior was analyzed through Tafel analysis, measurement of damage area, weight loss, and surface observation. Results described that corrosion current density was increased rapidly when chloride concentration excceded 600 PPM, and it was increased about 7.7 times in the case of 1000 PPM compared with 0 PPM. Potentiodynamic polarization experiment revealed that corrosion damage area and mass loss of specimen increased with chloride concentrations. When chloride concentration was further increased, the corrosion damage area extended to the entire surface. To determine damage tendency of pitting corrosion according to chloride concentration, the ratio of damage depth to width was calculated. It was found that the damage tendency decreased with chloride concentrations. Thus, 6061-T6 aluminum alloy damage becomes larger in the width direction than in the depth direction when a small amount of chloride is contained in an acid rain environment.

Ni Sulfamate-chloride 전기도금 용액에서 전류밀도와 첨가제의 농도 변화가 Ni 박막에 미치는 영향 (Effects of the Changes of Current Density and Additive Concentration on Ni Thin Films in Ni Sulfamate-chloride Electrodeposition Baths)

  • 윤필근;박덕용
    • 한국표면공학회지
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    • 제51권1호
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    • pp.62-70
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    • 2018
  • Sulfamate plating solution containing a small amount of chloride bath was fabricated to study the properties of the electrodeposited Ni thin films. Effects of the changes of current density and additive concentration on current efficiency, residual stress, surface morphology and microstructure of Ni thin films electrodeposited from Ni sulfamate-chloride baths were investigated. The current efficiency was measured to be more than about 95%, independent of the changes of current density and saccharin concentration in the baths. Residual stress of Ni thin film was appeared to be the compressive stress modes in the range of $5{\sim}30mA/cm^2$ current density. Maximum compressive stress was observed at the current density of $10mA/cm^2$. Compressive stress values of Ni thin/thick films were increased to be about -85~-100 MPa with increasing saccharin concentration from 0 to 0.0195 M(4 g/L). Surface morphology was changed from smooth to nodule surface appearance with increasing the current density. Smooth surface morphology of Ni thin films electrodeposited from the baths containing saccharin was observed, independent of the saccharin concentration. Ni thin/thick films consist of FCC(111), FCC(200), FCC(220), FCC(311) and FCC(222) peaks. It was revealed that the FCC(200) peak of Ni thin films is the preferred orientation in the range of $5{\sim}30mA/cm^2$ current density. The intensity of FCC(200) peak was gradually decreased and the intensity of FCC(111) peak was increased with increasing saccharin concentration in the baths.

Effects of pH and Chloride Concentration on Corrosion Behavior of Duplex Stainless Steel and Titanium Alloys Ti 6Al 2Nb 1Ta 1Mo at Elevated Temperature for Pump Impeller Applications

  • Aymen A., Ahmed;Ammar Yaseen, Burjes;Ammar Yaseen, Burjes
    • Corrosion Science and Technology
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    • 제21권6호
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    • pp.454-465
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    • 2022
  • The objective of this study was to determine effects of temperatures and pH of sodium chloride solution with MgCl2 ions on corrosion resistance of duplex stainless-steel X2CrNiMoN22-5-3 (DSS) and Ti 6Al 2Nb1Ta1Mo (Ti). Effects of sodium chloride concentration on corrosion resistance were also studied. Corrosion behavior and pitting morphology of duplex stainless steel (DSS) and Ti alloys were evaluated through potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). It was found that a decrease in pH significantly reduced the corrosion resistance of both alloys. Changes in chloride concentration and temperature had more substantial impact on corrosion behavior of DSS than on Ti alloys. Pitting corrosion was formed on DSS samples under all conditions, whereas crevice corrosion was developed on Ti samples with the presence of magnesium chloride at 90 ℃. In conclusion, magnesium chloride ions in an exceedingly strong acidity solution appear to interact with re-passivation process at the surface of these alloys and influence the resulting surface topography.

비색판별법을 이용한 콘크리트의 표면염화물량 산정 및 매립철근의 건전도 평가 (Calculation of the Surface Chloride and Estimation for the Soundness of Embedded Rebar by Using Colorimetric Distinction Method)

  • 이문환;이진우
    • 콘크리트학회논문집
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    • 제15권6호
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    • pp.794-801
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    • 2003
  • 건축물의 요구성능에 대한 관심이 점차 높아짐에 따라 건축물의 성능평가를 통하여 사용연한을 예측하고 건축물의 수명을 연장시키거나, 새롭게 재구성하려는 노력이 계속되고 있다. 그러나 아직 염화물에 의한 성능저하 평가에 있어 그 비용의 문제와 평가과정의 전문성 등의 많은 난점을 가지고 있다. 본 연구는 콘크리트 내부의 염화물침투 깊이를 측정하는 간이적 방법인 비색판별법을 이용하여 염화물에 의한 성능저하평가를 하고자 비색판별법의 적용가능성을 검토 후 변색위치의 침투염화물량을 정량분석하였다. 또한, 이를 이용하여 콘크리트 표면염화물량을 산정하고 철근위치 염화물량의 예측 및 한계염화물량에 도달시간 예측의 실용적 평가수단을 제시하였다. 염화물에 의한 철근콘크리트 구조물의 성능평가에 있어 간이평가 수단인 비색판별법의 활용에 따라 샘플수의 다량확보를 통한 신뢰수준의 향상을 이룰 수 있을 것으로 사료된다.

Sulfamate-Chloride Bath에서 Co 농도의 변화에 따른 Ni-Co 필름의 특성 변화 (Property Changes of Ni-Co Film with the Change of Co Concentration in Sulfamate-chloride Bath)

  • 윤필근;박덕용
    • 한국표면공학회지
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    • 제53권1호
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    • pp.1-8
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    • 2020
  • Sulfamate-chloride baths were fabricated to study the properties of the electrodeposited Ni and NiCo thin films. The dependences of current efficiency, deposit composition of Ni and Co, residual stress, surface morphology and microstructure of electrodeposited Ni and NiCo thin films on CoCl2 concentration in sulfamate-chloride baths were investigated. The current efficiency was measured to be more than about 90%, independent of the changes of CoCl2 concentration in the baths. Residual stress of Ni and NiCo thin films was increased from about 45 to about 250 MPa with varying CoCl2 concentration from 0 to 0.210 M CoCl2 in the baths and then reached to a plateau, about 250 MPa above 0.420 M CoCl2 concentration. Nodular surface morphologies were observed at most CoCl2 concentrations in the baths except 0.210 M. NiCo thin film electrodeposited from the bath with 0.210 M CoCl2 concentration showed an acicular surface morphology. Pure Ni thin film consists of FCC(111), FCC(200), FCC(220), and FCC(311) peaks without any preferred orientation. On the other hand NiCo thin films make up of HCP(100), FCC(111), HCP(101), FCC(200), FCC(220) or HCP(110), FCC(311) or HCP(112) and FCC(222) peaks. It was revealed from the analysis of XRD result that FCC(111) peak at the NiCo thin film electrodeposited from the bath with 0.084 M CoCl2 concentration can be regarded as the preferred orientation. However the peak of the preferred orientation was changed to FCC(220) or HCP(110) above 0.084 M CoCl2 concentration in the baths. Then the intensity of FCC(220) or HCP(110) peak was gradually decreased with increasing CoCl2 concentration further. The crystalline size of pure Ni thin film was observed to be about 53 ㎛ and those of NiCo thin films were in the range of 35~45 ㎛.