• 한국구조물진단유지관리공학회 논문집
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• 제10권1호
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• pp.190-196
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• 2006

기존 연구에서 살펴보면, 철근콘크리트구조물에 발생한 화재로 인해 경화된 시멘트 페이스트와 골재의 수축과 팽창의 차이에 따라 조직이 와해되고, 열응력에 의해 균열이 발생하여 내구성이 저하한다. 그래서 성능저하의 정확한 진단은 일반적인 콘크리트구조물에서 방화성능저하의 매커니즘에 관한 기초가 요구되며, 고온에 노출된 콘크리트의 특성에 대한 기초 정보와 데이터는 성능저하의 정확한 진단을 위해 필요하다. 따라서, 본 연구는 다양한 콘크리트 시험체를 제작하여, 고온 환경에서 노출시켜, 폭열을 관찰하고, 공학적인 특성을 평가함으로서 화재피해를 입은 콘크리트구조물 성능저하의 빠르고 정확한 진단을 위한 기초적인 데이터를 제공하고자 한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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• pp.160-166
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• 1994

In general, the problems of strengthening and repairing of deteriorated or damaged reinforced concrete members are usually worked out in situ by externally bounding steel plates using epoxy resins, which has been recognized to be one of effective and convenient methods. But the disadvantages of strengthening/repairing concrete members with externally bonded steel plates include ; (a) deterioration of the bond at the steel-concrete interface caused by the corrosion of steel ; (b) difficulty in manipulating the plate at the construction site ; (c) improper formation of joints, due to the limited delivery lengths of the steel plates ; and etc. Therefore these difficulties eventually have led to the concept of replacing the steel plates by fiber-reinforced composite sheets which are characterized by their light weight, extremely high stiffness, excellent fatigue properties, and outstanding corrosion resistance. In the paper, for the reliability assessment of reinforced concrete beams externally strengthened by carbon fiber plastic(CFRP) laminates, an attempt is made to suggest a limit state model based on the strain compatibility method and the concept of fracture mechanics. And the reliability of the proposed models is evaluated by using the AFOSM method. The load carrying capacity of the deteriorated and/or damaged RC beams is considerably increased. Thus, it may be stated that the post-strengthening of concrete beams with externally bonded CFRP materials may be one of very effective way of increasing the load carrying capacity and stiffeness characteristics of existing structures.

• 콘크리트학회논문집
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• 제13권1호
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• pp.9-15
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• 2001

콘크리트 구조물의 성능저하는 여러 성능저하 요인들의 상호작용에 의해 발생한다. 특히 중성화는 시간의 경과에 따라 증가하는 대표적인 성능저하기구로 알려져 있다. 최근 들어 중성화 메카니즘에 관한 기초적인 연구와 더불어 중성화로 성능저하된 구조물의 내구성 증진을 위한 공법 및 기술개발이 활발히 진행중이다. 이에 본 논문에서는 기존에 제안되고 있는 중성화 단계에 따른 보수공법을 바탕으로 중성화된 콘크리트에 침투성 알칼리성부여제를 도포함에 따른 알칼리성 회복성상과 표면피복재의 종류에 따른 알칼리성 유지성능을 정량적으로 비교.분석하였다. 본 실험결과 알칼리성부여제를 토포함에 의해 촉진중성화에 의해 pH가 저하된 콘크리트의 알칼리성 회복성능을 확인 할 수 있었으며, 알칼리성부여제 도포후 표면피복재에 따라 콘크리트의 알칼리성 유지성능은 큰 차이를 나타내는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.769-772
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• 2005

The river environments of many streams in korea have been deteriorate through the rapid industrialization and urbanization since the 1960s. In Germany and Japan, on the other hand, much efforts on the research and project have been made for the restoration of the deteriorated streams to close-to-nature. in order to restore the deteriorated streams, therefore, it is necessary to investigate such advanced technologies and materials. In view of this requirement, various research paths are being taken focusing on coarse aggregates to make multi-functional porous concrete having continuous voids so as to improve water and air permeability, acoustic absorption, water purification, and applicability to vegetation. The Purpose of this study is to investigate the method for recovery of the environment in the streams area using porous concrete block. the porous concrete block applies for test in the cheonggae-cheon have been monitored planting during six month. after 6 months, plant grows flourishing and reconstructed in state such as nature rivers.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.667-672
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• 2002

Concrete cooled to very low temperature cyclically is deteriorated by ice formation in micro-pores. Although the factors to the deterioration are various, storage at very low temperature is mentioned as one of the factors. In practice, storage of cryogenic structure is kept at very low temperatures, and as such, it is important to take into consideration the influence of storage at such low temperature on the deterioration of concrete. Thus, in this study, the influence of storage on the deterioration of concrete at minimum temperatures taking into consideration the different W/C and air content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.271-274
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• 2001

Recently, we are facing with the trend of demanding high durability concrete for creek structures. When creek structures are deteriorated, it is very difficult to repair them. The objective of this paper is to develop a mixing model for high durability creek concrete having 300kg/$\textrm{cm}^2$ compressive strength. According to the result of durability experiment, high durability concrete for creek structures has high resistance of air permeability, absorption, chloride diffusion, and chemical attack.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.429-432
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• 2000

Test methods by hydraulic oil or vehicular live load have been used for structural evaluation of prototype bridge. However it has been reported that the use of hydraulic jack has some disadvantages for the view of safety and economy, and the complete structural evaluation through each loading state can not be accomplished blocks is presented to overcome those demerits. To verify the application and safely of the use of concrete weight blocks during each loading state, it is applied to prototype deteriorated bridge. As a result, it could be evaluated the structural behavior completely using the concrete weight blocks

• 한국도로학회논문집
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• 제19권2호
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• pp.7-15
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• 2017

PURPOSES : Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests. METHODS : This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672. RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete. CONCLUSIONS :This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.829-832
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• 2006

The river environments of many streams in korea have been deteriorate through the rapid industrialization and urbanization since the 1960s. In korea, on the other hand, much efforts on the research and project have been made for the restoration of the deteriorated streams to close-to-nature. in order to restore the deteriorated streams, therefore, it is necessary to investigate such advanced technologies and materials. In view of this requirement, various research paths are being taken focusing on coarse aggregates to make multi-functional porous concrete having continuous voids so as to improve water and air permeability, acoustic absorption, water purification, and applicability to vegetation. The Purpose of this study is to investigate the method for recovery of the environment in the streams area using porous concrete painting block. the P.O.C block applies for test in the kyungan-cheon have been monitored planting during six month. after 6 months, plant grows flourishing and reconstructed in state such as nature rivers.

• Earthquakes and Structures
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• 제5권3호
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• pp.321-341
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• 2013

This paper investigates earthquake response of reinforced concrete regular frames subjected to rebar corrosion. A typical four-story reinforced concrete frame is designed according to Turkish Earthquake Code in order to examine earthquake response. Then different levels of rebar corrosion scenarios are applied to this frame structure. The deteriorated conditions as a result of these scenarios are included loss in cross sectional area of rebar, loss of mechanical properties of rebar, loss in bond strength and variations in damage limits of concrete sections. The frame is evaluated using a nonlinear static analysis in its sound as well as deteriorated conditions. The rebar corrosion effect on the structural response is investigated by comparing the response of the frame in each scenario with respect to the sound condition of the frame. The results shows that the progressive deterioration of the frame over time cause serious reductions on the base shear and top displacement capacity and also structural ductility of the corroded frames. The propagation time, intensity, and extensity of rebar corrosion on the frame are important parameters governing the effect of rebar corrosion on earthquake response of the frame.