• 한국구조물진단유지관리공학회 논문집
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• 제27권4호
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• pp.45-53
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• 2023

본 연구에서는 해양환경에 노출된 강부재의 표면염분과 부식량의 상관관계를 분석하기 위하여 해상강교량의 보강형 거더 부재와 강박스 실험체를 대상으로 표면염분량과 평균부식두께를 부재단위로 평가하였다. 표면염분은 월단위로 1년간 Bresle method를 활용하여 계측하였고, 부식량은 실험용 모니터링 강판에 발생한 부식생성물로 인한 중량감소량을 평균부식두께으로 환산하여 분석하였다. 표면염분과 부식량을 계측한 결과, 강부재의 형상이나 설치위치에 따라 상대적인 표면염분량과 평균부식두께의 차이가 나타났으며, 동일한 교량 내에 설치된 동일한 형상의 부재라도 부식량이 국부적으로 급격히 증가하는 것을 확인하였다. 표면염분과 부식량의 상관관계를 분석하기 위하여 표면염분에 따른 부식량 발생 경향을 평가하였으며, 부식량을 평가할 수 있는 평가식을 부재의 형상별로 분석하였다. 표면염분과 부식량의 상관관계 분석 결과, 표면염분의 영향으로 강부재에서 발생하는 부식량은 부재의 형상에 따라 약 1.15배까지 변화하는 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제12권2호
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• pp.10-19
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• 1984

The $3{\times}3{\times}30$ ($cm^3$) sized lumbers of Populus alba-grandulosa L. were treated with four fire-retardant solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate and aluminium chloride for 1, 15, 30, and 60 minutes and 1, 3, and 7 days. Thereafter they were air-dried and burned at high temperature about $1,800^{\circ}C$ and for short time of five minutes. This study estimated the relationship between absorbed chemical amounts and rate of weight loss or residual bending strength of these burned lumbers. The results were as follows: 1) In absorption amount of fire-retardant chemicals, diammonium phosphate showed the largest, aluminium chloride the smallest, but monoammonium phosphate and ammonium sulfate showed similar level. 2) The absorption amount of chemicals was decreased with the increase of specific gravity in the same species except aluminium chloride. 3) The rate of weight loss was decreased as the absorption amount of chemicals increased, especially monoammonium phosphate was most effective. 4) The MOR value of the residual bending strength was increased as the absorption amount of chemicals increased and especially monoammonium phosphate showed the most efficient effect. 5) Aluminium chloride showed more striking increase of MOR value of residual bending strength with the increase of absorption amount than any other chemical, therefore its MOR value was similar to the maximum MOR value of the most effective monoammonium phosphate. 6) The correlation between weight loss and MOR value of the residual bending strength was negative and aluminium chloride showed the most striking negative relation, but the others showed similar trends. 7) The correlation between work to proportional limit and absorption amount of chemicals was positive and the degree of increase in work to proportional limit was most in aluminium chloride, and the next, in monoammonium phosphate and diammonium phosphate in turn. 8) The correlation between work to maximum load and absorption amount of chemicals showed positive and diammonium phosphate revealed the best result and aluminium chloride showed better results than other two chemicals.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
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• pp.123-124
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• 1990

Seaside concrete structure is deteriorated by chloride-ion, sulphate and salt cristalization in concrete pore. Therefore the amount of these chemical substance should be analyzed for evaluating the durability of seaside concrete structure. In this study, the amount of chloride-ion in concrete was surveyed in order to estimate the damage state of concrete structure within am influence of seawater.

• 콘크리트학회논문집
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• 제20권4호
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• pp.415-421
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• 2008

콘크리트 중의 철근부식은 콘크리트 제조시 초기부터 콘크리트 중에 존재하는 염소이온과 기상작용 등의 환경요인에 의하여 외부로부터 침투하는 염소이온이 어느 값 (임계염화물량) 이상의 경우에 발생한다. 이 때문에 각 국에서는 콘크리트 중의 염소이온량의 상한치를 규제하고 있으며, 국가별 상황에 적절하게 상이한 방법으로 규제하고 있다. 따라서 본 연구에서는 콘크리트 중 염소이온량의 합리적인 규제방법을 제안하기 위하여, 단위시멘트량이 다른 콘크리트 중의 염소이온에 의한 철근부식 임계 염화물량을 실험적으로 산출하였다. 그 결과, 철근부식 임계염화물량은 단위시멘트량의 변화에 따라 크게 변화하는 것을 알 수 있었다. 또한, 실험으로부터 얻어진 철근부식 임계염화물량은 기존의 모델계산의 결과와 잘 일치함을 알 수 있었다. 현행과 같이 철근부식 임계염화물량을 콘크리트 단위체적 당의 양 (콘크리트 총량표기)으로 단위시멘트량에 관계없이 일률적으로 관리하면, 단위시멘트량 등의 콘크리트 배합조건, 환경조건의 변화 등이 철근부식 임계염화물량에 미치는 영향을 고려할 수 없을 것으로 판단된다. 따라서, 철근부식 임계염화물량을 단위시멘트량 당의 양 (시멘트 종량표기)으로 표기하는 것으로, 단위시멘트량에 관계없이 일정한 값으로 표시할 수 있기 때문에 합리적이라고 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.493-496
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• 2006

Steel corrosion in concrete is aggravated with the increase of chloride content in concrete. So, there are regulations in the total amount of chloride ions in concrete in Korea and Japan. The purpose of this paper is to propose a resonable method to regulate the amount of chlorides in concrete. In this study, the experimental results showed that it is rather reasonable to regulate the amount of chloride ions in cement than the total amount of the chloride ions in concrete.

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

• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.40-41
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• 2018

The purpose of this study is to compare the amount of critical chloride of rebar embedded in concrete according to the substitution rate of admixture. In order to determine the starting point of corrosion of rebar, electrodes were embedded in concrete, chloride was supplied, and OCP of rebar was observed in real time. The amount of the contaminants in the concrete surrounding the rebar was judged to be the critical corrosion chloride contents of the rebar at the start of the corrosion. As a result of the comparative evaluation, it was confirmed that the critical chloride contents of the rebar decreased with increasing the substitution ratio of the admixture.

• 한국구조물진단유지관리공학회 논문집
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• 제27권5호
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• pp.16-22
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• 2023

이 연구는 원전 콘크리트 배합설계를 모사한 콘크리트 시험체에 대하여 염수침지 실험을 수행하였으며, 시험체 깊이에 따른 염화물량과 XRF 성분의 상관관계를 분석하였다. 원전 콘크리트의 표면부의 염화물량은 염수 침지기간이 증가함에 따라 소폭 증가하였으나, 깊이 5.5 mm 이상의 콘크리트 시험체 내부 염화물량은 염수 침지기간이 증가함에 증가하는 경향이 뚜렷하게 나타났다. 콘크리트의 염화물량과 XRF 성분의 상관관계 분석결과, OPC 배합과 비교하여 FA가 20% 치환된 배합은 XRF 성분분석을 통한 Cl 이온의 구성비율과 염해저항성 평가결과의 상관관계가 매우 높게 나타났다. 이에 따라 FA가 20% 치환된 원전 콘크리트 배합에서는 반복적인 데이터 누적을 통해 XRF 성분분석을 통하여 염소이온분석 및 염해저항성능 평가가 가능함을 확인하였다.

• Structural Engineering and Mechanics
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• 제85권2호
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• pp.197-206
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• 2023

The deterioration caused by chloride penetration and carbonation plays a significant role in a concrete structure in a marine environment. The chloride corrosion in some marine concrete structures is invisible but can be dangerous in a sudden collapse. Therefore, as a novelty, this research investigates the ability of a non-destructive damage detection method named the Power Spectral Density (PSD) to diagnose damages caused only by chloride ions in concrete structures. Furthermore, the accuracy of this method in estimating the amount of annual damage caused by chloride in various parts and positions exposed to seawater was investigated. For this purpose, the RC Arosa bridge in Spain, which connects the island to the mainland via seawater, was numerically modeled and analyzed. As the first step, each element's bridge position was calculated, along with the chloride corrosion percentage in the reinforcements. The next step predicted the existence, location, and timing of damage to the entire concrete part of the bridge based on the amount of rebar corrosion each year. The PSD method was used to monitor the annual loss of reinforcement cross-section area, changes in dynamic characteristics such as stiffness and mass, and each year of the bridge structure's life using sensitivity equations and the linear least squares algorithm. This study showed that using different approaches to the PSD method based on rebar chloride corrosion and assuming 10% errors in software analysis can help predict the location and almost exact amount of damage zones over time.