• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.857-860
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• 1998

Reinforced concrete structure is deteriorated, as time goes on. So many repair materials are developed for the repair. But repair materials have not been adequately applied so far. Because the datum which evaluated the repair materials are not sufficient. The object of this study is estimation f repair materials that is in general use and establish method of application. To acquire the result, we have made experiments on chemical attack, carbonation and chloride permeability test. The carbonation and chloride permeability are very different. Some repair materials are poorer than portland cement mortar.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.293-298
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• 1995

This study experimentally evaluate the bonding performance of repair and strengthening materials. It is very important problem to justify bonding properties between repair and strengthening materials and old concrete. Many previous research and investigation showed that bonding strength of reinforcing materials determines the strengthening effect and the durability of repair work. Therefore, menifestation of bonding properties and the improvement of bonding performance of repair and strengthening materials are very important. In order to improve the perforamnce of repair work, it needs to investigate the behavior of bonding materials, such as stress distribution along the bonding area and the long term performance of the material. The target repair methods are steel plate addition technique and repair mortar method, and the test parameters studied in this paper include epoxy thickness, bonding surface texture, and bonding area.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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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.

• 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.

• International Journal of Concrete Structures and Materials
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• v.6 no.2
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• pp.87-100
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• 2012

The process of selecting a repair material is a typical one of multi-criteria decision-making (MCDM) problems. In this study Analytical Hierarch Process was applied to solve this MCDM problem. Many factors affecting a process to select an optimal repair material can be classified into quantitative and qualitative requirements and this study handled only quantitative items. Quantitative requirements in the optimal selection model for repair material were divided into two parts, namely, the required chemical performance and the required physical performance. The former is composed of alkali-resistance, chloride permeability and electrical resistivity. The latter is composed of compressive strength, tensile strength, adhesive strength, drying shrinkage, elasticity and thermal expansion. The result of the study shows that this method is the useful and rational engineering approach in the problem concerning the selection of one out of many candidate repair materials even if this study was limited to repair material only for chloride-deteriorated concrete.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.21-33
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• 2014

PURPOSES: The purpose of this study was to break away from the workforce method using cold-mix asphalt mixtures and has a constant quality and has develop repair materials of pre-production asphalt-precast types. METHODS: The selection of the repair material was determined as the results obtained through physical properties of materials and the field applicability. In case of repair materials, values obtained through Marshall stability test & the dynamic stability test & retained stability test as well as the site conditions was considered. In case of adhesive, test results were obtained through examination of the bond strength(tensile, shear) and the field applicability of the adhesive was examined through combined specimens to simulate field applications. RESULTS : According to the results of laboratory tests, in the case of repair materials, Marshall stability and dynamic stability, retained stability of cold-mix reaction type asphalt mixture is the highest. In the case of adhesive, two-component epoxy-urea has a very high bonding strength(tensile, shear) was most excellent. According to the results of field tests, when epoxy-urea was excellent workability. Also, the repair body through actual mock-up test did not occur large deformation and fracture after 12 months. CONCLUSIONS : A suitable repair material is cold-mix reaction type mixture of asphalt-precast, a suitable adhesive is a two-component epoxy-urea.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.202-209
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• 2023

In this study, microstructures and mechanical properties of repair materials using calcium sulfoaluminate (CSA) and/or amorphous calcium aluminate (ACA) cements were experimentally investigated. By XRD ansysis, the hydrates formed in repair materials were identified. In addition, the microstructures of repair materials were visually examined through SEM observation. Setting time of mortars made with repair materials were measured. The strength development and ultrasonic velocity of the mortars were also evaluated at the predetermined ages. As a result, it seems that ACA showed a benefit effect with respect to mechanical properties of mortars.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.571-578
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• 1997

In the repair and repair works, epoxy resins are widely used as repair materials. The successful concrete repairs and retrofit works depends on the quality of the repair and retrofit materials. Although many materials for the repairs and retrofit have been developed in many contries, information on the repair methods are somewhat limited. Futhermore, the repairs and retrofit methods are also largely dependent on those froms in other developed contries, it is necessary to initiate rather fundamental repair-related research. The purpose of this study is to investigate th physical and mechanical properties of epoxy resin which is commonly used in repairing concrte crack in RC structures. The basic physical properties such as specific gravity, gel point and shrinkage ratio as well as the mechanical properties such ad the tensile and compressive strength, elastic modulus were acquired by the standard test method (KS code). For the test results, the great deviations of physical and mechanical properties among the test materials were discovered and is, therefore, recommended that careful attentions should be give in selecting the epoxy resin by considering the characteristics of the repair materials and repair works.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.139-146
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• 2024

Various injection materials, such as asphalt-based injection materials, urethane-based injection materials, cement- based injection materials, and acrylic-based injection materials, are used for the repair of aged conduits and underground structures with cracks. In this study, research was conducted on an environmentally friendly acrylic- based leak repair material that exhibits good curing properties even in humid conditions and stability in temperature fluctuations. To compare the performance of the improved acrylic leak repair material with the existing acrylate injection material, experiments were conducted using KS standard methods, including underwater length change rate tests, underwater leakage resistance tests, and chemical performance tests. The comparative experiments revealed that the improved acrylic leak repair material showed no changes in shrinkage due to humidity, temperature variations, or chemical reactions compared to the existing acrylate injection material. In the underwater resistance test, the improved acrylic leak repair material did not show any leakage. Additionally, to assess the environmental impact of the improved acrylic leak repair material, acute fish toxicity tests and acute oral toxicity tests were conducted, and the results showed no mortality and no specific concerns with the test specimens. The experimental results led to the conclusion that the improved acrylic leak repair material is considered to be superior in performance, environmentally safe, and harmless to the human body. Based on various experimental results, it is inferred that the improved acrylic leak repair material is suitable for use as a repair material for cracks in manholes and underground structures compared to the existing acrylate repair material. This study aims to propose valuable data for future technological development by evaluating the applicability of acrylic leak repair materials.