• 어항어장
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• s.18
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• pp.69-77
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• 1992

고강도 콘크리트의 실용화 일환으로 설계기준강도 500kg/cm$^2$ 이상인 고강도 콘크리트의 현장 B/P 생산과 실대구조물의 시공성 및 강도, 온도 특성에 관한 연구를 수행하였다. 이러한 연구를 위해 현장 최적배합비 선정과 레미콘 운반시간에 따른 경시변화 시험을 수행하였고 실대구조물의 코아강도 및 콘크리트 내부온도를 측정하였다. 일반 현장재료와 장비의 사용으로도 고강도 콘크리트의 생산과 시공성을 확보할 수 있었으며 실대구조물의 코아강도가 500kg/cm$^2$ 이상을 나타냄으로써 고강도 콘크리트의 실용화에 대한 가능성을 확인할 수 있었다.

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.167-178
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• 1998

횡방향철근에 의하여 적절히 구속된 콘크리트 기둥은 강도증가 및 연성의 확보면에서 유리하다. 본 연구의 목적은 횡방향철근에 의하여 구속된 코아콘크리트의 크기,횡방향철근의 간격비 및 체적철근비 등의 변화에 따른 콘크리트 기둥의 극한강도를 포함한 최대하중 이전의 거동 및 최대하중 이후의 거동을 실험적, 해석적으로 고찰함으로써 콘크리트 기둥의 구속효과정도를 규명하려는데 있다. 본 연구에서는 횡구속된 콘크리트 기둥모형의 압축재하실험을 수행하였으며, 최대하중 이전의 거동에 대하여 연속체적 파괴와 소성을 고려한 3차원 모델링을 통한유한요소해석을 실시하였다. 또한 횡구속된 콘크리트 기둥의 변형률국소화 모델에 의한 파괴해석을 통하여 구속된 콘크리트 기둥의 최대하중 이후의 거동을 재현하였다. 해석결과는 압축재하실험의 결과와 비교, 분석되었으며, 이에 따른 구속효과를 규명하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.37-40
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• 2008

Recently, Construction Business, is changing very quickly, exceedingly needs to slim down the construction expensive by reducing material costs and the term of works. The term of formwork takes 25% of the term of works and costs 15% to 20% of the cost of construction. Hereupon, the purpose of this study is to investigate the Axial Strength of Centrifugall Formed Shell PC Columns that can reduce the term of formwork, the costs of material, the difficulty of throwing away the waste. Shell PC Column is loaded stirrups and manufactured at factory, so it has good points like construction's quality control and part's precision. However, it needs to be tested for checking bonded ability because it is set up at core and coverd with concrete. therefore this study is necessary three type of columns, which are a RC column, different type of two compressive strength core concrete columns and a Shell PC Column. By three columns, this study compare with and analysis three columns's bonded and Compressive Behavior abilities.

• Magazine of the Korea Concrete Institute
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• v.3 no.2
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• pp.97-104
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• 1991

고강도 콘크리트의 관용화일환으로 500㎏/㎠ 이상인 고강도 콘크리트의 현장 B/Ptodtks과 실대구조물의 시공성 및 강도, 온도 특성에 관한 연구를 위해 현장 체적백합비 선정과 레미콘 운반시간에 따른 경시변화 시험을 이행하였고 실대구조물의 코아강도 및 콘크리트를 내부온도를 측정하였다. 일반 현장재료와 장비의 사용으로도 고강도 콘크리트의 생산과 시공성을 확보할 수 있었으며 실대구조물의 코아강도가 500㎏/㎠ 이상을 나타내므로써 나타내므로써 고강도 콘크리트의 실용화에 대한 가능성을 확인할 수 있었다.

• Cement
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• s.166
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• pp.54-61
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• 2005

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.1-10
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• 2012

This paper presents an experimental result and suggests the confinement effect of headed cross tie in reinforced concrete(RC) columns subjected to cycling horizontal loads under constant axial load. Five RC columns specimens were manufactured, taking confined type of transverse reinforcement, whether or not using cross tie, end detail of cross tie (hooked or headed), and axial stress in column as major variables, Cyclic horizontal load applied to the columns under constant axial stress and the effect of cross tie to structural capacity of column was evaluated from the test. The column without cross tie failed showing bending deformation of hoop with crack in core concrete at low horizontal load while the column with cross tie showed quite improved strength and ductility by suppressing bending deformation of hoop as well as buckling of longitudinal bar at once even after crack in core concrete. At high lateral displacement, the column with hooked cross tie showed the failure pattern loosing the confining force of cross tie since the $90^{\circ}$ hooked part of cross tie was stretched out and the cracked core concrete lumps were came off. However, the column with headed cross tie showed very stable behavior since the head of cross tie effectively confined the hoop and longitudinal bars even at high lateral displacement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.101-111
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• 2005

In this study, it is investigated the modified modulus of elasticity of the reinforced concrete columns including the longitudinal reinforcing steels as well as the confinement effect of the core concrete due to the transverse reinforced steel through the literature reviews. Equations are derived in order to evaluate the modified modulus of elasticity for the reinforced compressive concrete including the confinement effect. The finite element analysis for the 20 story reinforced concrete building is undertaken as a case study depending on the steel ratio and modulus of elasticity, and the analysis results are discussed.

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.215-220
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• 1994

Results of an experimental investigation on the bearing strength and stiffness of concrete under dowel bars are summarized. The effects of concrete strength bar diameter, and location of the bar on concrete were studied. Based on test results, empirical equations are proposed to predict the, concrete bearing strength and stiffness under reinforcing bars. Cornparisions of analytical arid experimental results are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.519-520
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• 2009

The purpose of this research was to develop a very-early-strength dry-mix shotcrete without accelerator using a rapid-setting cement, to analyze the correlationship of test results among cube test, core test, pullout test and maturity

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3988-3997
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• 2010

Shotcrete was a mortar or concrete that is pneumatically projected at high velocity onto a subject. It has been applied for tunneling, underground big-spaces, slope stabilization. Shotcrete is increasing use in structure repair. The dry-mix shotcrete require a smaller equipment, easy maintenance, possible of very-earlystrength materials than wet-mix shotcrete, which make this process attractive and economic for structural repairs. It is common practice core compressive strength to the dry-mix shotcrete quality control. This test is very difficult estimating eraly-strength of Very-Early-Strength Dry-Mix Shotcrete. The purpose of this research was to analyze the correlation of test results among cube test, core test, pullout test and maturity. The correlationship analysis of test results among cube test, core test, pullout test and maturity showed more than 90%.