• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.170-171
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• 2021

This study compared the characteristics of the newly established JISA 5011-5 coal gasification slag fine aggregate with the characteristics of CGS generated in Korean IGCC through microscopic analysis. As a result of the study, similar results to K_CGS and J_CGS were found

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.149-150
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• 2023

Although concrete is a material widely used in the construction industry, it is very vulnerable to cracking and has a disadvantage in that durability deteriorates when cracks occur. When cracks occur, harmful factors are introduced through the micro-cracks of the structure, reducing durability. Therefore, in this study, as part of a study to alleviate the problems of maintenance and durability deterioration due to cracks in concrete structures, the mechanical properties of self-healing mortar according to the size of the capsule made of cement material were reviewed.

• Journal of the Korea Institute of Building Construction
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• v.21 no.4
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• pp.305-318
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• 2021

The aim of the research is providing the rheological performance range for manufacturing "mid-workability concrete". The mid-workability concrete means the normal strength range concrete mixture with high workability. Since there is not enough study or quantitative definitions on performance of the mid-workability concrete, in this research, the performance range for high workability of mid-workability concrete mixture using rheology. Because of the mixture characteristics of generally used normal strength concrete such as relatively high water-to-cement ratio and no SCMs, segregation of coarse aggregate should be prevent to achieve a successful high workability. From the experimental study in this research scope, 5 to 35 Pa.s of plastic viscosity was desirable to prevent segregation for nid-workability concrete, and general performance range with rheological parameters was provided.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.12
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• pp.165-172
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• 2019

The aim of the research is to evaluate the influence of various replacing ratios of supplementary cementitious materials(SCMs) such as fly ash(FA), blast furnace slag(BS), and both FA and BS on general properties including segregation resistance as a powder based high fluidity concrete of normal strength grade with water-to-cement ratio 0.40. Specifically, by replacing the SCMs with low density powders, it was assessed that the decreased segregation resistance due to the decreased viscosity by J-ring test. As a result of the experiment, from the general test, the mixtures with SCMs showed increased segregation resistance by increased viscosity as the references, while some segregation was shown from J-ring test due to the decreased density of fresh state mixture related with the capacity of delivering coarse aggregate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.243-251
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• 2022

The purpose of this study is to investigate experimentally the effect of polyethylene fibers with different tensile strength and aspect ratio on the properties of cementless composite. Three types of mixtures according to the types of polyethylene fibers and water-to-binder ratio were prepared and density, compressive strength and tension tests were performed. Test results showed that the mixture reinforced by polyethylene fiber with a low tensile strength by 10 % and a high aspect ratio by 8.3 % had a high tensile strain capacity by 11.7 %, a high toughness by 12.4 %, and a low crack width by 9.1 %. It was also observed that high tensile strain capacity and better cracking pattern could be achieved by increasing the water-to-binder ratio of composite although its strength is low.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.28-29
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• 2017

Recently, the tendency of the insulation of buildings to be important is making the buildings airtight. However, in order to get closer to the technology, it is necessary to improve the performance of walls and panels of buildings, but it is a problem due to the increase of the unit price. We will review the basic data on the density and table flow characteristics of high thermal insulation materials.

• 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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• 2018.11a
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• pp.157-158
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• 2018

In this study, the current tendency to replace a large amount of material admixture, which is fly ash (FA) and blast furnace slag (BS), into concrete is that high-grade cheese high admixture of high fluidity concrete In consideration of the substitution rate, we considered J-Ring to investigate the influence on the segregation resistance and the method of evaluating the classical segregation. In addition to the admixture replacement rate in the study results, the EIS using J-Ring became lower and the percentage of vehicles with segregation increased. Such a tendency is considered to be positive when J-Ring is used when segregation is judged if segregation degree is similar to EIS using J-Ring.

• Composites Research
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• v.19 no.4
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• pp.39-43
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• 2006

A decade ago, the technology of strengthening structures using FRP composites was primitive, with very few publications. Nowadays, the potential growth of research is achieved to the wide recognition of the importance of this new technology. In fact, significant practical applications have been preceded and the development of design methods have been achieved. However, the specific design methods for each applications are still lack of design skills in spite of the wide applications of FRP composites in the construction industry. The purpose of this paper is to report the development of design methods for FRP-strengthened structures by technical review design methods and guidelines of fiber reinforced composites.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.377-378
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• 2023

This study examined the effect of curing conditions on the compressive strength of dry mortar for floor. The compressive strength according to the relative humidity during curing was compared, and the influence of expansive additives on compressive strength under water curing was reviewed. As a result, low relative humidity conditions during curing was not effective in improving the compressive strength of dry mortar for floor, and it was judged that the continuous hydration reaction insufficient due to lack of the moisture supply. In order to improve compressive strength, high relative humidity maintenance was found to be an important factor. However, under water curing conditions, the compressive strength has decreased as a result of continuous volume expansion due to the use of the expansive additives.