• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.123-129
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• 2018

The aim of the research is providing a fundamental idea of reducing viscosity of cement based materials by replacing powder based material. With developing concrete technology, high performance concrete with high solid volume fraction has been used widely. Under the conditions of the high solid volume fraction due to the low w/c and replacement of SCMs, decreased fluidity is one of the critical problem, and thus plasticizer has been used to improve fluidity of the mixture. However, in rheological aspect, the fluidity of cement based materials can be defined with yield stress and viscosity, and using plasticizer only decreases yield stress without least controlling on viscosity. Therefore, based on the idea of Krieger-Dougherty model, a feasibility of wasted limestone powder from cement manufacturing process was used to decrease the viscosity of the mixture by replacing cement powder. According to a series of experiment, by replacing wasted limestone powder solely, there was a possibility of reducing viscosity was observed. Thus, in this research scope, it is considered to contribute on providing a fundamental idea of reducing viscosity with powder replacement and it is expected to contribute on further research using various conditions of replacing powders for reducing viscosity of cementitious materials.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.163-169
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• 2009

The research performed a test concerning the fluidity and strength of concrete manufactured by combining lime stone power, fly ash, and blast furnace slag into two and three component systems, aiming at evaluating rheological and dynamic properties of concrete by manufacturing High Flowing Self-Compacting according to the strength changes of three levels. As a result of the research, for High Flowing Self-Compacting of 30 MPa, the combination of lime stone power 20% and fly ash 30% for securing quality and strength and adjusting viscosity satisfied the required performance. For High Flowing Self-Compacting of 50 MPa, the combination of blast furnace slag 10% and fly ash 20% satisfied the fluidity and strength of the requirement performance. Also, for 70 MPa that has many power contents, the combination of blast furnace slag 20% and fly ash 10% for the increase of fluidity and the reduction of viscosity satisfied the required performance. It is judged that fly ash in all combinations can be used to secure viscosity and reduce concrete amount. In addition, it is judged that for High Flowing Self-Compacting according to the levels of compressive strength the combination of three component system including fly ash is more appropriate than the combination of two component system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.37-40
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• 2002

The purpose of this study is promote perfect of construction and progress of packing ability through comparison and analysis with quality, as placing ways and placing direction are changed. Kinds of concrete are general, high fluidity, and high Performance concrete. Classified with concrete as placing ways - direct ways, sheath way - and placing directing - flange direction, web direction - is analyzed section and strength of hardened concrete. The results of this study is belows the more fluid of concrete, the more useful to top-down method.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.15-18
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• 1998

In this paper, the properties of high performance concrete with fly ash and expansive additives are investigated. According to the experimental results, when 10% of fly ash and 5% of expansive additives are mixed in concrete mixture, the improvement of the quality in the side of the fluidity, strength and the prevent of the crack caused by drying-shringkage can be accomplished.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.19-22
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• 1998

This study is investigate the properties of high performance concrete at W/B of 35%, used with silica fume and CSA expansive additives, which is used to improve the concrete qualities and prevent the drying-shrinkage. According to the results, the fluidity of concrete shows a decline with the increase of replacement percentage of silica fume and proportions of expansive additives. A higher strength is obtained at 5% of replacement percentage of silica fume, while the compensation achieves in drying-shrinkage of concrete at 5% of expansive additives.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.841-846
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• 2000

The purpose of this study is promote perfect of construction and progress of packing ability through comparison and analysis with quality, as placing ways and placing direction are changed. Kinds of concrete are general, high fluidity, and high performance concrete. Classified with concrete as placing ways - direct ways, sheath way - and placing directing - flange direction, web direction - is analyzed section and strength of hardened concrete. The results of this study is belows the more fluid of concrete, the more useful to top-down method.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.925-928
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• 2000

In this paper, physical properties of cement mortar for floor using expansion agent are discussed varied with mixing time and curing temperature, delivery time and content of added water for preventing fluidity loss. According to experimental results, slump loss shows high with elapse of time And as curing temperature goes up, it also show high when curing temperature goes up and time lag between mixing and casting increases. As curing temperature goes down, drying shrinkage shows to be decreased. But it shows decline tendency with increase of added water content.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.179-180
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• 2015

Recently, admixture manufacturers have improved the performance of admixtures to solve problems caused by high viscosity of high performance admixtures, and accordingly, it is expected to affect fluidity of concrete using admixtures. Therefore, in this research, how each kind of HAE affects consistency curve of cement mortar was examined.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.219-228
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• 2019

The aim of the research is to provide a fundamental data of low viscosity typed superplasticizer (SP) on cement-based materials incorporating various supplementary cementitious materials (SCMs). As a relatively new product, low-viscosity typed SP has introduced for high performance concrete with high viscosity due to its high solid volume fraction with various SCMs. However, there are not enough research or reports on the performance of the low viscosity typed SP with cement-based materials incorporting SCMs. hence, in this research, for cement paste and mortar, fluidity and rheological properties were evaluated when the mixtures contained various SCMs such as fly ash, blast furnace slag, and silica fume. From the experiment conducted, it was checked that the low viscosity typed superplasticizer decreased the plastic viscosity of the mixture as well as the yield stress. From the results of this research, it is expected to contribute on introduction of new type SP for high performance concrete or high-viscous cementitious materials.

• Korean Journal of Materials Research
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• v.22 no.6
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• pp.309-315
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• 2012

Metal foam has many excellent properties, such as light weight, incombustibility, good thermal insulation, sound absorption, energy absorption, and environmental friendliness. It has two types of macrostructure, a closed-cell foam with sealed pores and an open-cell foam with open pores. The open-cell foam has a complex macrostructure consisting of an interconnected network. It can be exploited as a degradable biomaterial and a heat exchanger material. In this paper, open cell Mg alloy foams have been produced by infiltrating molten Mg alloy into porous pre-forms, where granules facilitate porous material. The granules have suitable strength and excellent thermal stability. They are also inexpensive and easily move out from open-cell foamed Mg-Al alloy materials. When the melt casting process used an inert gas, the molten magnesium igniting is resolved easily. The effects of the preheating temperature of the filler particle mould, negative pressure, and granule size on the fluidity of the open cell Mg alloy foam were investigated. With the increased infiltration pressure, preheat temperature and granule sizes during casting process, the molten AZ31 alloy was high fluidity. The optimum casting temperature, preheating temperature of the filler particle mould, and negative pressure were $750^{\circ}C$, $400-500^{\circ}C$, and 5000-6000 Pa, respectively, At these conditions the AZ31 alloy had good fluidity and castability with the longest infiltration length, fewer defects, and a uniform pore structure.