• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.228-229
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• 2015

In this research, properties of new crack repair materials using organic and inorganic composites (OAI) were investigated under various crack conditions. Especially, this study aims to develop new composites repair materials as needed to follow the crack and its repair method. Crack repair methods such as injection method and surface treatment repair method using self-healing capability for the practical industrial application were examined in comparison with normal crack repair method as a epoxy injection. From these results, it was confirmed that the sealing and injection effects through the cracks from field tests could be improved by OAI.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.817-822
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• 2002

The problem of the crack which occures from the reinforced concrete structure could be caused by the complexed factors. When the crack happen, it caused fatal blemish to manage and maintain the structure such as structural problem, licking, spalling, viewing Even though they study and work hard to solve this kind of problem in the world, there are no countermeasure for perfect prevention of crack. After the crack checked out, a method of repair-reinforcement has been studied and operated actively, Generally, occurance of the crack in the concrete structure could be taken as granted, no need to mention the damage from the crack, domestic construction try to hide it rather than repair basically, In many cases the construction amount for repairing the crack has to be made in the construction area and the amount is very expensive. To save the repaing fee, companys repair it under the meeting of their desire. it can be expected for the effection of the construction. For this reason, we compare a new injection method to solve the demerits of the present method, to save and use the merit of the present method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.111-112
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• 2014

This research focuses on the study that micro-crack of concrete is repaired to use self-healing technology. Self-healing concrete is widely studied in domestic and international construction field recently. Micro-crack(less than 0.3mm)of concrete is repaired using a crack repair stick which containing self-healing agents. Therefore, the crack on construction structure will be easily repaired by using a crack repair stick. Also experiment was proceeded because of evaluating the long term durability.

• International Journal of Railway
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• v.2 no.1
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• pp.30-36
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• 2009

Crack and its damage of structure concrete in both FBS and TBS ballastless track are presented. The cause of concrete crack is analyzed. According to corresponding quantitative equation, effective technical measures to depression crack of concrete are put forward, at the same time the rationality of elastic ratio for HGT has been proved. At last, by the analysis of the characteristic of high-speed train, which are serving in the open air, bearing fatigue load, the short time for maintenance window and high speed of service, technical requirement for concrete repair material, repair technology and repair tools of ballastless track structure are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.579-584
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• 1997

This experimentation is to apperciation an efficiency of repair for processing crack by corrosion of steel reinforcing, Crack on concrete by corrosion of steel reinforcing is the fact that the first crack appear on the surface of water because of supplying is of oxygen and water. The crack processing is on surface to be contacted by air and to bottom as mainly the vertical direction from a surface of water. The experimentation gives rise to crack in model by electricity. Crack by corrosion of steel reinforcing is more internal crack than external crack. since it is so. crack by corrosion of steel reinforcing have to attention to repair or intermal crack.

• Journal of Welding and Joining
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• v.29 no.2
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• pp.64-71
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• 2011

In this paper, crack propagation analyses in the inner diameter (ID) repair weld of the dissimilar metal weldment of a nozzle were performed using a finite element alternating method (FEAM). To calculate the theoretical solution for the crack tip stress intensity factor, a weak type singular integral equation consisted of crack surface traction and dislocation density function was constructed and solved in conjunction with the FEAM. A two-dimensional axisymmetric finite element nozzle model was prepared and ID repair welding was simulated. An initial crack, 10% depth of weld thickness, was assumed and crack propagation trajectory from the initial crack to the 75% depth of thickness was calculated using the FEAM. Crack growth versus time curve was also calculated and compared with the curves obtained from ASME code method. With the method constructed in this paper, crack propagation trajectory and crack growth time were calculated automatically and effectively.

• Architectural research
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• v.11 no.2
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• pp.27-34
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• 2009

The purpose of this study is to investigate the problem of crack repair materials and methods in existing concrete structure and to propose the effective injection method on crack repair by packer type. The result of this study is as follows. It is investigated that the crack width in the inner matrix of concrete structure is decreased about 30-40% than that in the surface of the concrete structure. Also it is showed that the possibility which could be monolithic with injection part became higher if the injection part is installed near to surface of concrete on the punching method to vertical direction against crack area. The injection of repair material can be poured smoothly under about $10N/mm^2$ pressure on the condition that cracks are monolithic with injection part without dust by drill. The method which is effective injection for a repair material is the punching method in compliance with coredrill. But, the research continuously is necessary about minimum injection pressure.

• Journal of the Korea Institute of Building Construction
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• v.6 no.2 s.20
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• pp.91-98
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• 2006

The purpose of this study is to investigate the problem of crack repair materials and methods in existing concrete structure and to propose the effective injection method on crack repair by packer type. The result of this study is as follows. It is investigated that the crack width in the inner matrix of concrete structure is decreased about 30-40% than that in the sulfate of the concrete structure. Also it is showed that the possibility which could be monolithic with injection part became higher if the injection part if installed near to surface of concrete on the punching method to vertical direction against crack area. The injection of repair material can be poured smoothly under about $10N/mm^2$ pressure on the condition that cracks are monolithic with injection part without dust by drill. The effective method to pour the injection repair material is the punching method by coredrill but several research to minimize injection pressure should be continually.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.515-518
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• 2005

A concrete is easy to happen crack. So it requires crack-repair work to solve quality deteriorations of a building because of cracks. When crack is filled with crack-repair materials, it is difficult to find out how depth it was injected. So in this study we evaluated the injection depth with using indirect and oblique methods, ultrasonic pulse measurement method of NDT. The results of this study showed that both methods are possible to evalute penetration depth of crack-repair materials and indirect methods is thought to be more useful one than obliqure one.