• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.241-242
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• 2019

This technology is a water leak repair technology using composite materials of concrete structures that block leakage of structures by injecting rapid microcement into the face of underground concrete to block water and injecting flexible glycidylacrylate. Rapid micro cement system repair materials are mixed with fine fibers to improve the flexural sensitivity of the material and to form a layer that blocks stabilized water at the back of the structure by allowing rapid and tight spatial filling during injection with high cohesion The glycidylacrylate repair material can control the expansion rate, and the external stress also has the characteristic that the form of the material is not destroyed or separated, which can also be applied to vibrating induced structures that produce repetitive fatigue loads, and has an effective durability in saline, alkali, acid (chloric acid, sulfuric acid, nitric acid).

• 한국도로학회논문집
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• 제18권1호
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• pp.43-55
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• 2016

PURPOSES : This study aims to develop a repair material that can enhance pavement performance, inducing rapid traffic opening through early strength development and fast setting time by utilizing MgO-based patching materials for repairing road pavements. METHODS : To consider the applicability of MgO-based patching materials for repairing domestic road pavements, first, strength development and setting time of the materials were evaluated, based on MgO to $KH_2PO_4$ ratio, water to binder ratio, and addition ratio of retarder (Borax), by which the optimal mixture ratio of the developed material was obtained. To validate the performance of the developed material as a repair material, the strength(compressive strength and bonding strength) and durability (freezing, thawing, and chloride ion penetration resistance) was checked through testing, and its applicability was evaluated. RESULTS : The results showed that when an MgO-based patching material was used, the condensation time was reduced by 80%, and the compressive strength was enhanced by approximately 300%, as compared to existing cement-based repair materials. In addition, it was observed that the strength (compressive strength and bonding strength) and durability (freezing and thawing, and chloride ion penetration resistance) showed an excellent performance that satisfied the regulations. CONCLUSIONS : The results imply that an emergent repair/restoration could be covered by a rapid-hardening cement to meet the traffic limitation (i.e. the traffic restriction is only several hours for repair treatment). Furthermore, MgO-based patching materials can improve bonding strength and durability compared to existing repair materials.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.402-407
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• 2002

Laminate tooling process is a fast and simple method to make metal tools directly for various molding processes such as injection molding in rapid prototyping field. Metal sheets are usually cut, stacked, aligned and joined with brazing or soldering. Through the joining process, all of the metal sheet layers should be rigidly joined. When joining process parameters are not appropriate, there would be defects in the layers. Among various types of defects, non-bonded gaps of the tool surface are of great importance, because they directly affect the surface quality and dimensional accuracy of the final products. If a laminate tool with defects has to be abandoned, it could lead to great loss of time and cost. Therefore a repair method for non-bonded gaps of the surface is essential and has important meaning for rapid prototyping. In this study, a rapid laminate tooling system composed of a CO2 laser, a furnace, and a milling machine was developed. Metal sheets were joined by furnace brazing, dip soldering and adhesive bonding. Joined laminate tools were machined by a high-speed milling machine to improve surface quality. Also, repair brazing and soldering methods of the laminates using the $CO_2$ laser system have been investigated. ill laser repair process, the beam duration, beam power and beam profile were of great importance, and their effects were simulated by [mite element methods. The simulation results were compared with the experimental ones, and optimal parameters for laser repair process were investigated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.353-358
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• 2001

The cement concrete pavements are designed twenty years of performance life in Korea. At the present time, some expressways have been elapsed seventy percent of performance life which are detecting local failures. The most repair methods using to repair failures are partial depth repair and full section repair. These methods are most important bonding strength between rapid curing materials and substrate concrete pavements. This study was performed to evaluate bonding strength of the composites section made of rapid curing material and substrate concrete pavements. The pull-out tester was used to test bonding strength for the composites section made of each materials. In the results of the test, the bonding strength values of the epoxy mortar and acrylic mortar are higher than those of the other materials. The performance life of repaired section is affected by various factor. The bonding strength of bonded composites section may be affect the performance life, significantly.

• 대한관절경학회지
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• 제9권2호
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• pp.180-185
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• 2005

목적: 본 논문의 목적은 Rapid Loc 기기를 이용한 관절경적 연골판 봉합술의 임상적, 방사선학적 결과를 평가하고자 하였다. 대상 및 방법: 44례를 대상으로 후향적으로 결과를 분석하였다. 퇴행성 병변이 동반되지 않은 단순 종파열로 진단되어 관절내시경하에서 Rapid Loc 기기를 이용하여 연골판을 봉합한후 평균 6개월이상의 추시가 가능하였던 환자 군을 대상으로 하였다. Orthopaedische Arbeitsgemeinschaft Knie (OAK) 평가 지표와 자기 공명 영상 촬영을 이용하여 임상적 방사선학적 결과를 평가하였다. 관절연 압통, 관절내 부종, McMurray 검사에서 양성인 경우는 임상적 실패로 간주하였다. 결과: 평균 연령은 33.4세 평균 추시기간은 15개월이었다. 임상결과는 우수 15례(34.1%), 좋음 20례 (45.5%), 양호 7례(15.9%), 불량 2례(4.5%) 였다. MRI상 Reicher 분류를 이용한 방사선학적 평가에서 grade 1 15례(33.3%), grade II 21례(50%), grade III 7례(16.7%)였으며, 임상적 실패는 8례(18%)였다. 술후 합병증은 1례에서 발생되었다. 결론: Rapid Loc 기기는 연골판 봉합술에 있어서 매우 우수한 결과를 보였으며, 삽입물이 유연하여 연골 손상이 적고, 사용이 간편하고 파열 부위의 압박 정도를 조절 할 수 있는 등 많은 장점이 있는 기법이라 사료된다.

• 한국구조물진단유지관리공학회 논문집
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• 제22권6호
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• pp.176-181
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• 2018

콘크리트 구조물은 시공 후 다양한 원인에 의해 물리적, 화학적 변형을 통해 물리적인 성능이 저하된다. 이러한 콘크리트 구조물의 성능저하는 사용수명을 감소하기 때문에 합리적인 보수보강이 필요하다. 최근 콘크리트 구조물의 효율적인 보수을 위해, 부착성능을 향상시킨 하이브리드 보수재료에 대한 연구가 활발히 수행되어오고 있다. 본 연구에서는 기존콘크리트와의 부착성능 및 수밀성을 향상시키기 위해 초속경 시멘트에 PVA 분말수지, 나일론 섬유, 라텍스를 혼입 한 하이브리드 보수재를 개발하였다. 보수재료의 성능평가를 위해 압축강도, 건조수축, 부착강도 실험을 수행하였다. 또한 미리 손상이 발생한 시험체를 제작한 후 보수 전후의 휨부착 성능평가를 수행하였다. 휨강도 평가결과, 기존의 초속경시멘트만 혼입한 시험체를 제외한 모든 실험체에서 110%~150%정도 휨강도가 크게 나타났고, 휨강도에 의해 발생된 균열패턴은 모든 실험체가 기존 콘크리트와 일체 거동하는 것으로 나타났다.

• International Journal of Concrete Structures and Materials
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• 제7권1호
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• pp.35-50
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• 2013

Rapid and effective repair methods are desired to enable quick reopening of damaged bridges after an earthquake occurs, especially for those bridges that are critical for emergency response and other essential functions. This paper presents results of tests conducted as a proof-of-concept in the effectiveness of a proposed method using externally bonded carbon fiber reinforced polymer (CFRP) composites to rapidly repair severely damaged RC columns with different damage conditions. The experimental work included five large-scale severely damaged square RC columns with the same geometry and material properties but with different damage conditions due to different loading combinations of bending, shear, and torsion in the previous tests. Over a three-day period, each column was repaired and retested under the same loading combination as the corresponding original column. Quickset repair mortar was used to replace the removed loose concrete. Without any treatment to damaged reinforcing bars, longitudinal and transverse CFRP sheets were externally bonded to the prepared surface to restore the column strength. Measured data were analyzed to investigate the performance of the repaired columns compared to the corresponding original column responses. It was concluded that the technique can be successful for severely damaged columns with damage to the concrete and transverse reinforcement. For severely damaged columns with damaged longitudinal reinforcement, the technique was found to be successful if the damaged longitudinal reinforcement is able to provide tensile resistance, or if the damage is located at a section where longitudinal CFRP strength can be developed.

• Architectural research
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• 제14권2호
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• pp.75-83
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• 2012

Buildings that are more than 10 years old generally have considerable repair and replacement costs due to the rapid deterioration of their systems. For public buildings in particular, which have national and social significance, considerable effort is required not only to ensure a long life cycle and safety but also to minimize the overall public expense. Along with increasing repair and replacement requirements, however, there have been problems related to the establishment of an accurate facility management budget. To address these concerns, a repair and replacement cost management system was constructed. This system manages both invested maintenance and forecast costs to establish a reasonable repair and replacement planning process and budget. The effectiveness of the system was verified through a pilot test targeting one of public Corporation (K).

• 한국구조물진단유지관리공학회 논문집
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• 제6권1호
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• pp.205-212
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• 2002

The deterioration rate of concrete structures in urban area is accelerated due to rapid urbanization and environmental pollution. Repair materials and methods newly introduced in Korea should be investigated whether they are appropriate for the urban environment in Korea. The creek concrete structures are exposed in severe environmental condition than others. Based on these background in mind, the study is focused on evaluation of performance on repair materials used to rehabilitate creek concrete structures. To evaluate the performance of repair materials, four kinds of repair materials were selected based on polymer emulsion. This experimental study was conducted on fundamental performance such as setting time, compressive strength, bending strength, bonding strength, thermal expansion coefficient, and durability performance such as chloride diffusion, carbonation, chemical attack, and steel corrosion rate. On the basis of this study, the optimal repair material which is proper to the environment condition can be selected and service life of creek concrete structures can be extended. As a result, the life cycle cost can be reduced and the waste of material resources will be cut down.

• ETRI Journal
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• 제32권4호
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• pp.642-644
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• 2010

With the rapid increase occurring in both the capacity and density of memory products, test and repair issues have become highly challenging. Memory repair is an effective and essential methodology for improving memory yield. An SoC utilizes built-in redundancy analysis (BIRA) with built-in self-test for improving memory yield and reliability. This letter proposes a new heuristic algorithm and new hardware architecture for the BIRA scheme. Experimental results indicate that the proposed algorithm shows near-optimal repair efficiency in combination with low area and time overheads.