• Title/Summary/Keyword: repair methods

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Performance Evaluation of Repair Methods for RC structures by Accelerating Test in Combined Deterioration Chamber and Long-Term Field Exposure Test (복합열화촉진실험 및 장기현장폭로실험에 의한 RC구조물 보수공법의 보수성능평가)

  • Kwon Young-Jin;Kim Jae-Hwan;Han Byung-Chan;Jang Seung-Yup
    • Journal of the Korean Society for Railway
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    • v.9 no.4 s.35
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    • pp.349-356
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    • 2006
  • At present, the selecting system and analytic estimation criterion on repair materials and methods of the deteriorated RC structures have not yet been set up in domestic. Under these circumstances, deterioration such as shrinkage crack, corrosion of rebar has been often occurred after repair, and this finally results in too frequent repairs. In this study, three types of repair methods were experimentally investigated by the accelerating test in a combined deterioration chamber and long-term field exposure test. Three types of repair methods applied in this study belong to a group of polymer cement mortar, which is commonly used in repair works. According to the results of this study, durability of repair mortar layers and corrosion properties of recovered rebar could be investigated in short period by the accelerating test in a combined deterioration chamber, which can simulate the condition of repeated high-and-low temperature and repeated dry-and-wet environment, spraying chloride solution and emitting $CO_2$ gas. After 36 month long-term filed exposure test in the coastal area, harmful macro-cracks are observed in the polymer cement mortar layer of some repair methods. These crack are considered to result from drying shrinkage of polymer cement mortar. Also, after 36 month exposure, amount of corrosion area and weight loss of rebar are found to be different according to the types of repair methods.

Repair methods of water leakage cracks using crack self-healing technologies for subway tunnels (균열자기치유 기술을 적용한 지하철 터널 누수공사)

  • Ahn, Tae-Ho;Bang, Sin-Young;Kim, Jeong-Mi;Shim, Kwang-Bo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.15-16
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    • 2015
  • In this research, the application of repair methods of water leakage cracks using self-healing technologies for subway tunnels is presented. In order to apply crack self-healing water stop agents and quick setting agents in subway tunnels, laboratory and field tests were performed based on various previous researches. Especially, this study focused on development of crack repair materials and their new repair methods. Therefore, various repair materials were examined for new repair materials with self-healing capability applied to crack sealing method and to patching repair method.

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Structural Analysis of Gas Pipeline Repaired by Carbon Fiber Composite Materials (탄소 섬유 복합재료로 보수된 가스 배관의 구조 해석)

  • Park, Sungho;Kim, Hansang
    • Journal of the Korean Institute of Gas
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    • v.18 no.2
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    • pp.62-68
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    • 2014
  • Composite repair methods besides welding methods such as surfacing and sleeve welding have been used as repair of damaged gas pipelines in foreign countries. Importance of safety management of city gas pipelines have been emphasized recently and our own repair manuals and codes for repair of city gas pipelines are required. It is right time to conduct research on the composite repair methods since the composite repair was introduced rather recently compared to the welding repair methods which have been investigated for long time. In this study, as a starting point of safety assessment of gas pipeline repaird by composite materials, structural analysis of gas pipeline repaired by carbon fiber composite materials was conducted using finite element analysis(FEA) method and the results was discussed.

Non-destructive Testing Methods to Evaluate the Effectiveness of Crack Repair Using Expoxy and Microcement (균열 주입부의 비파괴 검사에 의한 주입효과 판정에 관한 연구)

  • 최홍식;이시우;이호범;송영철;방기성
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.841-846
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    • 2002
  • Development on non-destructive testing methods were performed to evaluate the effectiveness of crack repair for test beams induced a crack. Cracked beams are repaired with expoxy and microcement, and then they are tested by two methods, the ultrasonic pulse velocity method and the transfer function method. It is proved that the ultrasonic pulse velocity method is very valid for the evaluation of the effectiveness on expoxy repair, and the transfer function method is very applicable to evaluate the effectiveness on microcement repair.

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Structural Analysis and Safety Assessment of KS D 3631 Gas Pipeline Repaired by Carbon Fiber Composite Material Sleeve (탄소섬유복합재료 슬리브로 보수된 KS D 3631 배관의 구조 해석 및 안정성 평가)

  • Choi, Jongmin;Kim, Hansang;Cho, Sungmin;Lee, Seungkuk
    • Journal of the Korean Institute of Gas
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    • v.20 no.5
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    • pp.96-103
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    • 2016
  • Proper repair methods of damaged city gas pipeline is important factor to safely transmit gas and to reduce economical loss caused by failure of gas pipelines. Repair methods such as surfacing, type-A and type-B welding and composite sleeve method have been used to repair damaged city gas pipelines. In this paper, among repair methods, composite sleeve repair methods were conducted since they are rather simple processes and their repair quality is not sensitive to workers' ability compared with other repair methods. We discussed composite repair processes especially using carbon fiber prepregs and the experimental results.

Antifuse Circuits and Their Applicatoins to Post-Package of DRAMs

  • Wee, Jae-Kyung;Kook, Jeong-Hoon;Kim, Se-Jun;Hong, Sang-Hoon;Ahn, Jin-Hong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.1 no.4
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    • pp.216-231
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    • 2001
  • Several methods for improving device yields and characteristics have been studied by IC manufacturers, as the options for programming components become diversified through the introduction of novel processes. Especially, the sequential repair steps on wafer level and package level are essentially required in DRAMs to improve the yield. Several repair methods for DRAMs are reviewed in this paper. They include the optical methods (laser-fuse, laser-antifuse) and the electrical methods (electrical-fuse, ONO-antifuse). Theses methods can also be categorized into the wafer-level(on wafer) and the package-level(post-package) repair methods. Although the wafer-level laser-fuse repair method is the most widely used up to now, the package-level antifuse repair method is becoming an essential auxiliary technique for its advantage in terms of cost and design efficiency. The advantages of the package-level antifuse method are discussed in this paper with the measured data of manufactured devices. With devices based on several processes, it was verified that the antifuse repair method can improve the net yield by more than 2%~3%. Finally, as an illustration of the usefulness of the package-level antifuse repair method, the repair method was applied to the replica delay circuit of DLL to get the decrease of clock skew from 55ps to 9ps.

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Study on the Inspection of Repairing Materials and Methods for Concrete Structures (콘크리트 보수 재료 효과 분석 및 공법기준관련 연구)

  • Kim, Do-Gyum;Oh, Kwang-Chin;Ahn, Sang-Ku;Park, Jung-Jun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.317-320
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    • 2006
  • In this paper, in order to inspect effect of marketed repair materials, it inspected first the repair material through laboratory work by repair method. After we carry out laboratory work and choice the construction with ongoing deterioration to inspect performance of repair materials, we apply the repair materials there. This results will be make use of reference whenever selection of repair materials and repair method. Also which will be used basic data for repair construction code.

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Fire Resistant Performance after Application of Repaired Materials for Fire-Damaged Reinforced Concrete Column (화재피해를 입은 철근콘크리트 단주시험체의 보수재료 적용 후 내화성능 평가)

  • Sim, Sang-Rak;Ryu, Dong-Woo
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.5
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    • pp.147-154
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    • 2020
  • Currently, there are no specific repair methods for RC structures damaged by fire, and repair methods are applied when durability deteriorates due to aging. In addition, a number of recent studies have been reported that have conducted fire resistance assessment of the repair materials themselves, assuming exposure to high-temperature environments such as fires. However, researches that evaluate the fire resistance performance of the repair materials by applying existing repair materials to the actual fire damaged reinforced concrete structures are very rare. Therefore, in this study, a number of existing repair materials were applied to fire-damaged concrete column to compare and evaluate the fire resistance performance with the original cover concrete.

A Study on the Effect of Rivet Layout on the Stress Variation in Doubler Repair (보강재 수리시 리벳 배열이 응력 변화에 미치는 영향 연구)

  • Moon, Ju-Yeon;Shin, Ki-Su
    • Journal of the military operations research society of Korea
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    • v.36 no.1
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    • pp.91-102
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    • 2010
  • Doubler repair is one of the frequently applied methods to repair cracks which occur at the structure of aircraft weapon systems. The requirement of the doubler repair for some of aging aircraft has increased more recently. However very few researches have been conducted until now. In this paper, the effect of the various doubler repair methods was evaluated. Especially, the relationship between the array of revet and the effect of stress concentration was investigated. To calculate variation of the stress with different repair methods, commercial FEA program was utilized. As a result, it was shown that the main factor for the variation of stress is pitch and number of revet line. Furthermore the optimized array of revet for the specific geometries of doubler was suggested.

Studies on Repair of Reinforced Concrete Structures(II) - Their Influence on Flexural Performance - (철근콘크리트 구조물의 보수 공법연구(II) - 휨 거동 비교 -)

  • 김병국;신영수;홍기섭;이차돈;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.219-224
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    • 1995
  • A series of 15 reinforced concrete beams was tested to explore the effects of polymer repair on damaged beams. The key parameters for this study were the repair materials, repair methods, repair depths and repair locations. The repaired specimens failed by a typical flexural mode, showing minor interface failure. The results show that epoxy, polyester resins and latex modified cementitous mortars are effective for repairing the concrete beams. The results also show that the depth and the location of the repair do not change significantly the flexural preformance of the repaired beams.

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