교량 바닥판은 대형 차량 및 제설제와 같은 다양한 환경 요인으로 인해 급속히 악화되는 부재이다. 한국에 건설된 교량의 수명이 길 어짐에 따라 교량 바닥판의 교체 수요가 증가 할 것으로 예상된다. 다른 국가에서는 프리 캐스트 바닥판을 이용한 급속 교량 건설 기술이 열화 된 교량 바닥판의 교체 수요 대응을 위해 적극적으로 사용되고 있다. 본 연구에서는 국내 교량 바닥판의 상태평가 데이터를 수집 및 분석하여 교량 바닥판 열화 모델을 제안 하였다. 또한 교량 규모의 관점에서 열화된 교량 바닥판의 미래 대체 수요를 예측하였다.

This paper presents an experimental study to evaluate complex deterioration resistances of concretes according to addition of modified sulfur. The complex deterioration tests were performed to concretes with freezing-thawing and deicing chemicals. From the test result, it was confirmed that the complex deterioration resistances of modified sulfur cement concrete was higher than that of normal concrete.

Concrete has been recognized as a material which is resistant to the high temperature, but chemicophysical property of concrete is changed by the high temperature. So, mechanical properties of concrete may be reduced. Therefore, concrete is evaluated mechanical properties for safety inspection. However, research of ultrasonic pulse method is not much. Therefore, the purpose of this study is to Non-Destructive Test of 30, 70, 110MPa concrete exposed high temperature using ultrasonic pulse velocity.

Visual inspection has generally been applied to examine the coating deterioration. However, it was difficult to evaluate an anti-corrosion performance of paint film. In this study, thus, to quantitatively evaluate an anti-corrosion performance of paint film under various corrosion enviornent, change in the impedance paint coating was evauated using EIS (Electrochemical Impedance Spectroscopy).

This paper presents an experimental study to evaluate complex deterioration resistances of concretes according to addition of modified sulfur. The complex deterioration tests were performed to concretes with freezing-thawing and deicing chemicals. From the test result, it was confirmed that the complex deterioration resistances of modified sulfur cement concrete was higher than that of normal concrete.

Concrete has been recognized as a material which is resistant to the high temperature, but chemicophysical property of concrete is changed by the high temperature. So, mechanical properties of concrete may be reduced. Therefore, concrete is evaluated mechanical properties for safety inspection. However, research of ultrasonic pulse method is not much. Therefore, the purpose of this study is to Non-Destructive Test of 30, 70, 110MPa concrete exposed high temperature using ultrasonic pulse velocity.

Visual inspection has generally been applied to examine the coating deterioration. However, it was difficult to evaluate an anti-corrosion performance of paint film. In this study, thus, to quantitatively evaluate an anti-corrosion performance of paint film under various corrosion enviornent, change in the impedance paint coating was evauated using EIS (Electrochemical Impedance Spectroscopy).

Indices are selected for the evaluation of deterioration of coated steel, and an evaluation method is proposed for each index. The evaluation methods proposed in this study are then applied on the existing inspection data measured on site, and the correlation between the resulting evaluation scores and service life of the coating is derived statistically. This correlation called to as the deterioration model can be used to determine the performance grade for the durability of coated steel.

Recently, interests for maintenance of transmission tower are increasing to extend life of structures and reduce maintenance cost. However, existing classical diagnosis method of corrosion deteriorated degree on the transmission tower steel members, visual inspection, has a problem that error often due to difference of inspector’s individual knowledge and experience. In order to solve the problem, this study carried out to develop the corrosion deterioration inspection tool for transmission tower steel members. This tool is composed of camera equipment and computer-aided diagnosis system. We standardized the photographing method by camera equipment to obtain suitable pictures for image processing. Diagnosis system was designed to evaluate automatically degree of corrosion deterioration for member of transmission tower on the basis of the RGB color image processing techniques. It is anticipated that developed the corrosion deterioration inspection tool will be very helpful in decision of optimal maintenance time for transmission tower corrosion.

This study was conducted for the development of degradation model for the coated steel member in the atmospheric environment. Field inspection data was assessed against the existing evaluation factors which were proposed by the related research process. A correlation between evaluated degradation score and service life of coated steel member was plotted on the graph, and degradation of the coated steel member could be evaluated by quantitative analysis method.

Selection of a typical four companies products of domestic structural one-component sealant, high temperature, low temperature, room temperature to set up the environment for each of 80, -20, 20 ℃ and the left and right displacement of the test piece 30, 15, 0% of the maximum compression / expansion It was carried out by the repeated fatigue.

Waterproofing materials applied in underground structures are commonly exposed to environmental factors such as rain water, vibration, structural movement. Particularly in the case of rain waters, the pollutants and chemical substances penetrate into the waterproofing layer surface and cause complex degradation. Approaching this problem with only conventional leakage preventative measures may prove difficulties in solving it. In this regard, 3 dimensional material evaluation methods (waterproofing system structure) should be employed over 2 dimensional methods, and a testing method that allows the simultaneous testing of various degradation conditions found in underground environments is necessary.

Oxidative and thermal degradation of alkanolamines for a promising CO2 capture technology of absorption might cause decrease in CO2 capture efficiency and formation of hazardous byproducts. In this study, characteristics of a representative absorbent of monoehtanolamine (MEA) were examined for a long term operation using a laboratory scale absorption system. An CO2 absorption system with ID 56 mm and absorption zone height 100 cm was developed for the characterization. Absorption solution of 30 wt% MEA was circulated at 100 mL/min to treat air with 15% CO2 and 1 ppm NO at 10 L/min. Temperatures of absorber and stripper were maintained at 40℃ and 120℃, respectively. For the course of 5 weeks continuous operation, MEA concentration was decreased approximately by 70% and CO2 removal efficiency was dropped from 95% to 65%. Ionic byproducts of NH4 +, NO2 -, and NO3 - were accumulated up to 48 g/mL, 0.2 g/mL, and 1.5 g/mL, respectively, tracking the variation of MEA concentration. Formation of various organic byproducts were also observed.

To suggest the preliminary data for effective maintenance of bridge structures, the damage patterns of expressway bridges are quantitatively analyzed in the present study. The defects are the primary damage, and the deterioration occurred around the joint.

This study, depending on the concrete mix material by performing the test on the basis of the wet and dry condition and freeze-thaw, and to elucidate the difference in the corrosion initiation time of there steel, in both environments, it is an object of correlation coefficient derived through the results of the accelerated corrosion test in a laboratory corrosion period of the structure of the marine environment.

Bridge decks are rapidly deteriorated by various environmental effects such as heavy vehicle and deicing salt, etc. For bridge owners in Korea, therefore, it is important to understand the defect characteristics and causes of deterioration of bridge decks as well as to predict the future need for bridge deck replacement based on proper deterioration models. Finding a solution to the problem, in this research, the site investigation for 76 domestic old bridges were undertaken and deterioration models of bridge decks were proposed by analysing service year-condition index relationships of more than 500 bridges.

Steel structure such as steel bridges are severely affected by the corrosion, and thus has to be maintained by periodic inspection and repetitive painting. In this study, existing empirical models for the degradation of coating are reviewed which is used for evaluation of corrosion, and in addition applied to definition of the state inspection criteria and condition rating by further research.

This study established key factors causing deck slab deterioration based on GPR database of 747 highway bridges, and predicted deck slab damage rates with respect to bridge service life. To minimize the influence of bridge service life on deck slab deterioration, the deck slab damage rate database was corrected based on a linear regression model of bridge service life vs. deck slab damage rate. The corrected deck slab damage rates were analyzed to determine correlation considering the number of snowy days, the amount of snowfalls, the number of freeze-thaw days, average winter temperature, altitude, the amount of deicing chemicals and equivalent traffic volume, and then both the number of freeze-thaw days and the amount of deicing chemicals were determined to be key factors causing deck slab deterioration. The complex deterioration considering both key factors was represented deck slab damage rate charts, and the average deck slab life was derived. The results of this study will be used as a guideline for highway bridge maintenance to identify the progress of deck slab deterioration for a given bridge and predict the time required deck slab rehabilitation.

최근에 건설분야 RC구조물의 시공도중 및 완공 이후에 이산화탄소 및 염소이온 등의 외기환경 노출과 콘크리트자체의 열화로 구조물의 사용성 및 구조성능 저하를 초래할 수 있다. 재료 및 시공적 측면에서 콘크리트의 탄산화 및 균열과 철근부식을 억제하고 제어할 수 있는 다양한 기술과 연구결과가 개발되고 소개되고 있다. 본 특집기사에서는 RC구조물을 건설하는데 있어 콘크리트의 내외부적인 요인에 의해 발생될 수 있는 열화와 그에 대한 대책과 관련된 최근기술 및 공법을 소개함으로써 관련기술에 관심을 갖고 있는 실무자나 연구자에게 유용한 자료를 제공하고자 한다. 첫째로, 동절기에 시공되는 옥외노출 콘크리트 수평부재에 동결융해로 인한 사용성 및 내구성 저하의 발생원인과 저감방법을 조사하는 기술을, 두번째로, 해상에 건설되는 콘크리트 토목구조물의 염해로 인한 콘크리트 및 철근의 열화요인과 대책에 대해 케이슨 구조물의 시공사례소개와, 마지막으로, 콘크리트의 수축에 의한 균열문제를 해결하기 위해 개발된 원통거푸집을 이용한 팽창콘크리트의 구속팽창 시험방법에 대한 개요와 활용사례에 대해 소개한다. 향후, 콘크리트 구조물의 열화에 따른 보수 및 보강에 관련된 첨단기술을 다시 소개하는 장을 마련할 수 있었으면 합니다.

Multi-physics nondestructive evaluation(NDE) technologies were proposed for monitoring section-loss and breakage of strands and tendons in prestressed girders moved from an actual bridge. The primary NDE technologies include Magnetic flux(MFL), Electrical resisticity(ER), Half-cell Potential (HCP), and Linear-polarization(LPR).