• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.71-74
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• 2005

The viscosity of high-flowability paste is very high compared to normal concrete for the low water-binder ratio(W/B). Therefore, high-flowability concrete is positively necessary to high-range water reducing agent. High-Flowability paste can make much higher fluidity with no occurrence of segregation, by its higher viscosity and lower yield value than normal concrete. The flowability of high-flowability paste must be evaluated not only by convention consistency test such as slump test but also by the base of the rheological properties of the fresh concrete. The purpose of this study is to analyze the fluidity of high-flowability paste according to the addition ratio of the Melamine Sulphonate high-range water reducing agent.; high-flowability paste is considered as Bingham plastic fluid with the rheology parameters of the plaste viscosity and yield value.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.73-74
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• 2015

As this study is one related to ultra high strength concrete using crushed coarse limestone aggregates among the series of experiments for improving the economic inefficiency of the ultra high strength concretes used for high rise structures, it has analyzed the flowability of ultra high strength concrete according to the variation of blended fine aggregates. As a result of analyzing the characteristics of fresh concrete, it is determined that the application of ultra high strength concrete would be difficult in case of a mix using blended fine aggregates as lower flowability than the mix using limestone crushed fine aggregate only was shown in all mixes using blended fine aggregates.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.71-72
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• 2015

As this study is the one related to the ultra high strength concrete essentially used for high rise buildings, it has analyzed on the flowability of ultra high strength concrete according to the variation of coarse aggregate and fine aggregate. The coarse aggregate was planned as two types including Granite Aggregate (GA) and crushed coarse Limestone Aggregate (LA) while fine aggregate was planned as four types including Sea Sand (SS), Limestone Crushed Fine Aggregates (LFA), Electric Arc Furnace Oxidizing Slag Aggregates (EFA) and Crushed Sand (CS) to perform experiment with a total of eight variables. As a result of analyzing slump flow, 500mm concentration time, U-Box and L-Flow, etc. among the characteristics of fresh concrete, a mix using LA+LFA is determined to show high flowability in case of applying ultra high strength concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.31-35
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• 2003

High-Flowability Concrete has many advanced properties and been focused on their workability. Because of the difficulty in understanding of the quality of High-Flowablity Concrete just using slump properties, many studies have been carried out rheological properties influenced on concrete fluidity. In this paper, for the purpose of expecting some level of rheological properties, the change of rheological properties of High-Flowability Concrete with dosages and types of superplasticizer, and various addition amounts addictives were investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.19-24
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• 1995

Most difficulties in inducing high flowability of general strength concrete arise from the segregation of aggregates due to the shortage of cementatious binders. To solve the problem, our research team has concentrated on finding the binders to link a gap between coarse and fine aggregates, under the condition not to influence a concrete strength. As a result of using stone powder or a middle class of aggregate size mostly used for asphalt pavement(Max. dia 13mm), we found that flowability of concrete increased significantly without aggregation and decrease of compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.209-210
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• 2011

This study is aimed to draw a optimum combined fiber mix condition to improve spalling resistance and flowability of ultra high-strength concrete. As a result, W/B 12.5% concrete specimens were prevented spalling with PE0.05+ PP0.1, PE0.05+NY0.1 and W/B 12.5% concrete specimens were prevented spalling with all of combined organic fiber mix condition. But There is no significant influence of steel fiber under 5% volume ratios to prevent spalling. In the scope of this study, we suggest that condition of optimum volume ratio PE0.05+NY0.1 is to improve spalling resistance, flowability and residual compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.53-56
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• 2005

High flowable concrete was first developed in 1988 to achieve durable concrete structures. High flowable concrete can improve workability sharply reason why the concrete has properties of resistance to segregation, filling ability, passing ability without compacting. Therefore, as we apply a high flowable concrete to a large dimensional tunnel which constructed in special environment, we can get workability, strength and durability required. Tunnel lining concrete with a large dimension has to use necessarily fly ash and slag for the properties of high flowability and watertight. We can expect improvement of workability and durability, mitigation of hydration, reducing shrinkage, enhancement of watertight by using cementitious materials. This paper proposes investigations for establishing a mix-design method and high flowability-strength testing methods have been carried out from the viewpoint of making a standard concrete tunnel lining with large dimension a standard.

• Journal of the Korea Concrete Institute
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• v.15 no.5
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• pp.739-746
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• 2003

Various researches on the application of polymer dispersions to the cement mortar and concrete have been carried out in many countries like America, Japan and Germany and so on due to their high performance and good modification effect. PAE of polymer dispersion widely used in situ was employed that the high flowability may be induced in the cement mortar. In order to investigate the modification of cement mortar with high flowability by PAE and fracture mode of adhesive strength properties in tension of that, experimental parameters were set as PAE solid-cement ratio(P/C) and cement: fine aggregate(C:F) and the experiments such as unit weight, flow, consistency change, crack resistance and segregation that inform on the general properties have been done. Adhesion in tension is measured with a view to comprehending the properties and fracture mode in tensile load. Consistency change of cement mortar modified by PAE did grow better as the ratio of PAE solid-cement increased and was much superior to that of resin based flooring such as polyurethane and epoxy which recorded the loss of consistency in 90 min. after mixing. Adhesive strength in tension increased with continuity during curing period and showed the maximum in case of C:F=1:1 and P/C=20%.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.1-7
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• 1995

In this paper, we decribed the basic elements required for the practical usage of super flowing concrete. The flowability and filingability of fresh concrete was measured by using six different testing methods. Also, two actual size members were used for investigating characteristics of the hardened concrete through variious experiments. As the result of the experimentation, the developed super flowing concrete shown high flowability and fillingability good enough for the requirement. Furthermore, inner uniformity of the no-vibrated concrete was verified by testing distribution of aggregates and core cylinders. Therefore, quality control and workability of concrete can be secured by using the super flowing concrete even without vibrating However, it ha been felt that development of easy evaluation methods for the super flowing concrete is in need.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.195-196
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• 2018

The Research is underway to utilize heavyweight concrete for various applications. One of them is to use heavy concrete as a marine concrete such as a breakwater to resist wave. Marine concrete is often complex in shape and requires high fluidity. When the heavyweight concrete is high fluidity, there is a high risk of segregation due to the high density of the coarse aggregate. Therefore, we evaluate the fluidity of heavyweight concrete using heavy fine aggregate. As a result of the fluidity evaluation of the heavyweight concrete, the fluidity of the heavy fine aggregate was similar to that of ordinary concrete. Therefore, it is considered that the use of heavy fine aggregate in the development of high fluidity heavyweight concrete will be one of the methods.