• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.17-18
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• 2015

In the case of concrete recently manufactured with a concrete mixing truck, although aggregate and cement are used as the main ingredients, from a costs savings perspective, low quality aggregates are processed and used as concrete aggregate. In the case of these low quality aggregates, the unit volume and unit binder weights are increased for manufacturing, and due to this problems such as dry shrinking of the architecture and economic infeasibility have arisen. Therefore by changing the aggregate material and the unit binder weights that are currently being distributed, this research analyzes the influence on concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.25-30
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• 2001

The purpose of this study is to present a basic data about the workability of high strength concrete to apply to a field of construction work. The main parameters are as follows; environmental temperature, elapsed time and the use of mineral admixture or not under the same mixing proportions. From the result, Adding amounts of superplasticizer to get a target slump were different in the respective temperature condition. Slump loss according to elapsed time was influenced by environmental temperature. the amount of superplasticizer and the slump loss were decreased by using mineral admixture(garnet powder) and by making concrete under lower temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.269-274
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• 2001

The purpose of this study is to evaluate basic properties of artificial aggregate using concrete sludge according to mixing ratio. Cement, waste phosphogypsum and Powder of blast furnace slag are used with binder of artificial aggregate. Specific gravity, absorption are tested for basic property, and impacting, abrasion and crushing tests are done for characteristics of strength on the aggregate, including comparison with crushed stone. Bry specific gravity was ranged about 1.16 to 1.30 the test result of the aggregates and shape is round In the result of tests, it is concluded that qualities of the aggregates using concrete sludge are slightly lower than crushed stone but it is similiar with sintering artificial lightweight aggregate in high temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.707-714
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• 2001

This paper presents the fundamental study on rational manu(acture of Very High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the VHS concrete(target compressive strength : over 1,000 kgf/$cm^{2}$) which is easily workable (target slump flow : 60$\pm$l0cm), The main variables studied are; 1) test variables to find the optimum replacement ratio of mineral admixture, 2) test variables to find a rational water-binder ratio, a proper binder content, 3) test variables to find the method for reduction of slump loss, 4) test variables to know the influence of air entrainment on frost resistance. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume, and water reducing agent(slump loss reduction type). We found that it is unnecessary to entrain air for freeze-thawing resistance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.41-44
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• 2005

The aim of this study is to develop experimentally ultra high-strength concrete with compressive strength over 100MPa with current materials by important factors to influence the compressive strength of concrete. There are so many factors which influence the manufacturing of ultra high-strength concrete. But the experimental factors selected in this study are the sand aggregate ratio, the silica fume replacement ratio, the type of aggregate. the type of superplasticizer, the fiber mixing ratio. The results of this experimental study show that. it is possible to applicate in the field

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.39-43
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• 2010

The surfacing of bridge-decks are object to secure trafficability and to protect bridge face from impact load of traffic volume and other external conditions. But the deformation of pavements and cracks happen due to the damage of the bridge-decks surfacing from the increase of the traffic, short maintenance period and continuous vibration of bridge. This test is to make the 3-type high performance concrete that has different mixing ratio and is added the blast furnace slag, fly ash and silica respectively, and to compare 3-type high performance concrete of normal high strength concrete of $400kgf/cm^2$ strength through the static loading test and fatigue test. And test specimen is united floor slab and pavement for the durability of bridge.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.89-92
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• 2006

This study has focused on the possibility for recycling of tailings from the Sangdong tungsten mine as powder of superfluidity self-compacting concrete. The experimental tests for slump-flow, time required to reach 500mm of slump flow(sec), time required to flow through V-funnel(sec) and filling height of U-box test(mm) were carried out in accordance with the specified by the Japanese Society of Civil Engineering(JSCE). The result of this study, in case of superfluidity self-compacting concrete mixed with tailings, slump-flow was decreased with increasing mixing ratio. But time required to reach 500mm of slump flow(sec), time required to flow through V-funnel(sec) and filling height of U-box test(mm) were satisfied a prescribed range.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.409-410
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• 2009

The eco-cement concrete using fly-ash was produced for the improvement of the compressive strength of the eco-cement concrete under the long term age, and compressive strength test, drying shrinkage test, uniaxial restraint shrinkage cracking test, and bond test were carried out. In this study, the cracking resistance performance was investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.437-440
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• 2003

This study has focused on the possibility for recycling of tailings from the Sangdong tungsten mine as powder of self-compacting concrete(SCC). The experimental tests for slump-flow, reaching time to the slump-flow of 500mm, V-funnel and U-box were carried out in accordance with the specified by the Japanese Society of Civil Engineering(JSCE). The result of this study, in case of SCC mixed with tailings, slump-flow was decreased with increasing mixing ratio. But reaching time slump-flow of 500mm, V-funnel and U-box were satisfied a prescribed range. The mechanical properties including compressive strength, splitting tensile strength and static modulus of elasticity were checked with the requirements specified by Korean Industrial Standard(KS). The compressive strength of SCC was decreased with increasing replacement, splitting tensile strength and static modulus were similar to those of normal concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.489-492
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• 2003

The results of an experiment on the sound absorption of the porous concrete and its influence on the compressive strength are reported in this paper. Two different sizes of coarse aggregate of 5~13, 13~20mm, and the design void ratio of 20, 25 and 30 percent for a given size of aggregate were used. In the compressive strength, an aggregate of the size of 5~13mm is much higher strength than that of the 13~20mm, In the sound absorption experiment, the size of aggregate of 5~l0mm is much higher sound absorption than that of the 13~20mm. The sound absorption ratio was increased as the design void ratio. As a result, Porous concrete sufficiently have the performance of sound absorption.