• Journal of the Korea Institute of Building Construction
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• v.10 no.4
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• pp.3-9
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• 2010

Fire resistance and material properties of high-strength concrete (W/B 21.5%, 28.5%) with OPC, BS and FA were tested in this study. Main factors of the test consisted of fiber mixing ratio and W/B. Two types of fiber (NY, PP) mixed with the same weight were used for the test. The fiber mixing ratios were 0%, 0.05%, 0.1%, and 0.2% of the concrete weight. After performing the test, Under the W/B level of 21.5% and 28.5%, the spalling was effectively resisted by using the high strength concrete with fiber mixing ratios of 0.05%~0.1%. Compressive strength, flowability and air content are similar those of the fiberless high-strength concrete with the same W/B.

• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.313-319
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• 2018

For the entire world, due to the increased risks of explosion and terrorisms, damages on human life and properties have been increased. Regarding this issue, research on high performance fiber reinforced cementitious composite (HPFRCC) with the protecting performance for the building structures or military facilities against explosion or bombing has been increased (important). Among a series of the research, using emulsified refined cooking oil(ERCO) to reduce the autogenous shrinkage may cause some adverse effect on performance of the mixture such as increased viscosity, decreased fluidity, air content, and strength. Hence, in this research, based on the optimum design of HPFRCC induced by previous research, the influence of ERCO adding timing and dosage on autogenous shrinkage and fundamental properties were analyzed. As a result, it was revealed that 0.5% of ERCO should be added right after the mixing is most effective for the quality of HPFRCC such as fluidity, strength development and autogenous shrinkage reducing.

• Journal of the Korea Institute of Building Construction
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• v.10 no.3
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• pp.49-56
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• 2010

The purpose of this study is to examine the effect of variations in the mix rate of PVA fiber and the replacement ratio of non-sintering Hwangtoh on non-sintering Hwangtoh mortar and concrete mixed with PVA fiber. For water to binder ratio, mortar and concrete were both 50%, and PVA fiber mix rate was 0% and 0.3%. The replacement ratio of non-sintering Hwangtoh was 0, 25, 50 and 75(%) for mortar, and 0, 15, 30 and 50(%) for concrete. The properties of the mortar and concrete were compared and analyzed in 4 different levels, and the results can be summarized as follows. The replacement ratio of 30% of the non-sintering Hwangtoh, and the PVA fiber mix rate of 0.3% is determined to result in concrete of high quality, including strength and fluidity, and crack control by plastic shrinkage.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.419-427
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• 2017

In order to examine the possibility of practical use of aluminate cement concrete at low-temperature environment with insulation method, an experimental studies on flowability, setting time, freezing temperature, size variation and compressive strength of the mortar at low-temperature were conducted. Compressive strength was increased in use of CSA, aluminate cement with gypsum. Workability and physical properties were improved by using aluminate cement and gypsum. In addition, freezing resistance and physical properties were improved by applying the insulation curing method. Especially, when alumina cement and gypsum were used together, the insulation curing method was more effective in improving the compressive strength.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.41-49
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• 2018

The purpose of this study is to develop a floor mortar construction technique which has high strength and inherent mechanical properties and does not cause cracks due to shrinkage after construction. It has been demonstrated that compressive strength, bending strength, flow with floor mortar, and crack reduction performance. As a result, it was confirmed that the developed floor mortar had the same or better performance comparing with the existing foreign products. The results of this experiment can be used as a validation material for high performance and high flowable mortar construction technology with excellent material performance, economical efficiency and construction ability by securing the required performance as floor mortar and selecting the optimal formulation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.44-49
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• 2019

The purpose of this study is to analyze the fundamental characteristics of concrete with the change of reject ash(Reject ash=Rj) in the mixed aggregate where single grain aggregate of different grain size and aggregate of opposite grain size are mixed together, to analyze the possibility of a mixed aggregate system that premixes at an aggregate manufacturing plant and delivers it as one aggregate. As a result of the experimental study, it was found that the grain size regulation is satisfied if the mixed aggregate(CSb+SS) is substituted for about 5% of Rj. In the case of the fluidity slump, slump flow and air volume, it was found that they decrease as the substitution ratio of Rj increases, while the compressive strength increases as the substitution ratio of Rj increases. Therefore, it is analyzed that it would contribute greatly to an improvement of quality such as improvement of compressive strength if adequate fluidity and air quantity are secured by the water reducing agent and AE agent while premixing the Rj, which is disposed of by landfill, with about 5% of the mixed aggregate.

• Journal of the Korea Institute of Building Construction
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• v.21 no.4
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• pp.269-279
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• 2021

Palm Oil Fuel Ash(POFA) has been widely used to replace Portland cement to enhance the mechanical properties and durability of concrete. However, it reduces the workability of concrete due to the high content of unburnt carbon and its angular shape requiring the usage of superplasticizer to ensure a proper flowability. In this study, effects of different types and dosage of superplasticizer on the early mechanical and hydration properties of cement paste containing micro-POFA were evaluated using mini-slump test, early compressive strength, TGA, XRD, and SEM. The results indicated that the flowability of cement paste containing micro-POFA reduced as the replacement ratio of micro-POFA increased. As the dosage of superplasticizer increased, the flowability was also increased. In addition, the usage of superplasticizer reduced the early compressive strength, and the strength decreased with an increase in the dosage of superplasticizer. It was confirmed that superplasticizer hindered the formation of C-S-H leading to a relative increase in the formation of Ca(OH)₂.

• Journal of the Korea Institute of Building Construction
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• v.22 no.2
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• pp.125-136
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• 2022

This research is to reduce the formwork leakage of high-fluidity concrete caused by insufficient accuracy of formwork fabrication widely used for high-fluidity concrete to general strength concrete. However, in the actual construction site, because of the insufficient accuracy of formwork fabrication may cause leaking concrete of mortar through a gab of the formwork. Therefore, in this research, which builds on previous research into providing thixotropy with PVA and Borax, the use of thixotropy to reduce high-fluidity mortar leakage was evaluated. The results of the experiment proved that the use of thixotropy with PVA and Borax can contribute to reduction of the formwork leakage of high-fluidity mortar. This finding is expected to lead to further research on reducing leakage of high-fluidity concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.45-46
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• 2015

Recently, the large amount of sulfur is globally generated by the development of the petroleum refining industry every year. In this study, without the use of the sulfur with a high melting point used in the previous studies, the modified sulfur mortar with addition of a melting point of about 65℃ were tested to determine their distribution and strength properties according to the mixing method and curing conditions. This study is a test to find out the Density, Absorption and Table Flow of the modified sulfur and general sulfur. As result, general industrial sulfur flow was lower, showed a high absorption rate.

• Journal of The Korean Digital Architecture Interior Association
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• v.5 no.1
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• pp.17-23
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• 2005

To begin with, this research arranged this concepts by analyzing paper a reference paper. So, the theory was arranged by approaching the ideal, formative and contemporary side. In order to type characteristics expression of organic design, after year 2000 printed in "Interiors" journal analyzed the contents based on interior works. 1. A type of metaphorical expression, order and the imitations of animals and plants. 2. A type of non liner, and dynamical balance and irregularity. 3. A type of mass of indeterminate form. 4. A type of fluidity by a curved line and a curved surface.