• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.212-218
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• 1995

This study experimentally evaluated the performance of damaged section which was repaired using polymer materials in reinforced flexural flexural members Six different materials, two types of polymer, two types of polymer-cement and two types of cement, were used by means of injection method on prepacked concrete and spray mortar patching method. As results, the repair works could be done easily and surfaces of the repaired section were smooth.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.81-82
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• 2020

In this study, after applying a silicate-based impregnation and polymer-based coating to fire damaged high strength concrete, carbonation resistance was evaluated to compare and evaluate the carbonation depth according to the type of surface repair materials. As a result of the experiment, it was confirmed that the carbonation resistance was increased in the case of the concrete with the surface repair materials compared to the control specimen without the surface repair materials. In particular, in the case of the polymer-based coating agent, it was confirmed that the carbonation hardly progressed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.109-110
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• 2023

Domestic ultra-hard road repair materials require a lot of time before the road can be opened to traffic. Therefore, in this study, Methyl Methacrylate (MMA) based road repair material was used to improve the above problems. Furthermore, the basic physical properties of MMA-based pavement repair materials are examined to confirm their suitability in concrete pavements. For this study, two types of MMA road repair materials (A type and B type) were selected. Then, the curing of the test specimens prepared for painting was carried out under three conditions. The experimental items were viscosity (drop time) and drying time (set to touch, dry-hard). As a result of the experiment, viscosity (drop time) was faster in type A than in type B. The drying time results were as follows. In the case of set ti touch, both type A and type B dried in about 10 minutes regardless of the curing conditions. In the case of dry-hard, regardless of the curing conditions, A type dried longer than B type, but it dried faster than conventional road repair materials. Therefore, within the scope of this study, it is considered that A type has a high potential for utilization as a road repair material.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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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.

• International Journal of Concrete Structures and Materials
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• 제6권3호
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• pp.199-207
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• 2012

Concrete is an economical construction material and for that reason it is widely used in buildings and infrastructures. The use of deicing salts, expansion joint failure, and freeze-thaw cycles have led to concrete bridge girders experiencing corrosion of steel reinforcement and becoming unsafe for driving. The goal of this research is to assess the effectiveness of current and possible repair techniques for the end region of damaged prestressed concrete girders. To do this, three American Association of State Highway and Transportation prestressed concrete girders were tested to failure, repaired, and retested. Three different repair materials were tested including carbon fiber, glass fiber, and surface mounted rods. Each different repair material was also tested with and without injected epoxy. Comparisons were then made to determine if injecting epoxy had a positive effect on stiffness and strength recovery as well as which repair type regained the largest percentage of original strength.

• 콘크리트학회논문집
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• 제24권4호
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• pp.361-368
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• 2012

보수 보강재는 강도, 안정성, 내구성, 모재와의 부착력 등 많은 특성이 필요하며, 최근 변형경화형 시멘트 복합체(strain-hardening cement-based composite, SHCC)가 기존의 재료를 대체할 수 있는 성능으로 많은 연구가 이루어지고 있다. 팽창형 SHCC는 팽창재를 이용하여 수축이 발생하는 SHCC의 단점을 보완하여 성능을 개선시킨 복합체로 이를 이용해 보강재의 성능을 만족시키면서 동시에 강도 증진 효과를 가져올 수 있을 것으로 예상된다. 따라서 이 연구에서는 SHCC 보강재의 강도, 팽창재 대체 여부 및 보강 두께를 변수로 하여 휨 성능을 평가하였으며, 실제 보강에 적용 시 기초 자료로 활용하고자 한다.

• 한국주거학회논문집
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• 제22권4호
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• pp.83-92
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• 2011

Apartment is settled down as a main housing type and massive supply has been conducted since 1990's. The government has focused on the housing supply to improve the housing number and cut its price. On the contrary, the management of the housing has been neglected to get an early deterioration. Since 1995's, various ways have been made to improve and maintain the building function and performance. Among these, the long-term repair plan has played a main role to manage the housing condition and plan the repair schedule for preparing the massive cost of repair such as a roof proof, elevator change. The long-tern repair plan provides the repair time and repair rate according to various construction types. Most of the management agent apply the repair standard into the field area. But the repair time could not reflect the present condition and bring into the wrong maintenance. Therefore, the repair time for the long-term maintenance plan would be revised and reflected from the material and technology development. |n this study, it aimed at improvement for the repair time in various construction types which are provided in the long-term repair plan. For this, the 22 management agents are surveyed directly. This study shows that the repair time of the painting are correspondent to the repair time of the long-term plan irregardless of the painting materials. Most of other areas would correspondently similar to the long-term plan. This study could not include the building location, material and other haracteristics. Therefore, the further study would be needed to reflect the building and materials attributes to get the detailed repair time.

• 한국농촌건축학회논문집
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• 제12권4호
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• pp.1-11
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• 2010

This study is a research examining reshaped pattern in the perspective of repairing parts and materials through repairing renovation of registered cultural properties constructed in modern times and results are as followings. Repairing construction of registered cultural properties of Jollanamdo according to parts is shown numerously in the order of roof, walls and windows, and mostly outworn as time passes on and leakage were the main cause of repair. Also when original shape was damaged by previous repair in the past, and this was another reason of repairing. It was surveyed that among the repairing job repair of damage occurred on the part of roofing area including water leakage, corrosion and damage of roofing material, and damage of groove channel were the most main cause of repair. Especially when roof leakage is occurred by outworn of roofing materials, this cause corrosion and damage of materials due to the damage of leakage parts and this cause repeating cycles of worse leakage again and again. Main repairing materials which deform the original shape of registered cultural properties were confirmed as copper plate used on the roof. Copper plate showing high frequency of application which replaces groove slate or cement roofing tile used on the roof before has high durability and anti-corrosion but it is considered improper material to recover original shape.

• 건축역사연구
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• 제21권4호
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• pp.81-92
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• 2012

Historic buildings are history of human kind and a crystal of culture. Therefore, we have a responsibility and obligation to succeed to descendants. Once such heritage is damaged, it is hard to restore its original form. Thus, various attempts to preserve its value and authenticity have been made internationally. Among these, the international preservation tendency of historic building in terms of materials has been given to the preservation of materials as well as the preservation of appearance. In accordance with such trend, Korea also presented an equivalent general principle, and has managed historic buildings with the separate related instruction. The most general method to preserve historic buildings in Korea is a repair work. Since the foundation of Korea, the repair work tendency has been carried out in the principle of phenomenon change and original form maintenance. But, such tendency focuses on the appearance such as style, structure and trimming method, and there is insufficient consideration on the authentic preservation of materials. Accordingly, this study attempts to examine preservation principle and methods in the repair works, and also to investigate the afforestation condition for the restoration work. And, by suggesting preservation method of authentic materials, it aims to prepare the reference for the future repair work.

• Computers and Concrete
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• 제32권3호
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• pp.287-302
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• 2023

Corrosion of reinforcing bars in reinforced concrete structures due to chloride attack in environments containing chloride ions is one of the most important factors in the destruction of concrete structures. According to the abundant reports that the corrosion rate around the repair area has increased due to the macro-cell current known as the incipient anode, it is necessary to understand the effective parameters. The main objective of this paper is to investigate the effect of the kinetic parameters of corrosion including the cathodic Tafel slope, exchange current density, and equilibrium potential in repair materials on the total corrosion rate and maximum corrosion rate in the patch repair system. With the numerical simulation of the patch repair system and concerning the effect of parameters such as electromotive force (substrate concrete activity level), length of repair area, and resistivity of substrate and repair concrete, and with constant other parameters, the sensitivity of the macro-cell current caused by changes in the kinetic parameters of corrosion of the repairing materials has been investigated. The results show that the maximum effect on the macro-cell current values occurred with the change of cathodic Tafel slope, and the effect change of exchange current density and the equilibrium potential is almost the same. In the low repair extant and low resistivity of the repairing materials, with the increase in the electromotive force (degree of substrate concrete activity) of the patch repair system, the sensitivity of the total corrosion current reduces with the reduction in the cathode Tafel slope. The overall corrosion current will be very sensitive to changes in the kinetic parameters of corrosion. The change in the cathodic Tafel slope from 0.16 to 0.12 V/dec and in 300 mV the electromotive force will translate into an increase of 200% of the total corrosion current. While the percentage of this change in currency density and equilibrium potential is 53 and 43 percent, respectively. Moreover, by increasing the electro-motive force, the sensitivity of the total corrosion current decreases or becomes constant. The maximum corrosion does not change significantly based on the modification of the corrosion kinetic parameters and the modification will not affect the maximum corrosion in the repair system. Given that the macro-cell current in addition to the repair geometry is influenced by the sections of reactions of cathodic, anodic, and ohmic drop in repair and base concrete materials, in different parameters depending on the dominance of each section, the sensitivity of the total current and maximum corrosion in each scenario will be different.