• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.121-126
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• 1994

In this study, several rheological properties of binder pastes and concrete are investigated for the development of commercially available fly ash super-flowing concrete. Fly ash contents with 5 leves(0, 10, 20, 30, 40%), slag contents with 6 levels(0, 5, 15, 25, 35, 45%), and water-binder ratios with 4 levels(30, 33, 36, 39%) are selected for test variables to evaluate the super-flowing characteristics of binder pastes. For the estimation of the workability of super-flowing concrete, slump flow, funnel time, box height, and L-flow are measured and compared. As the results, the flow is decreased and the viscosity is increased with increasing fly ash content. Super-flowing concrete is succesfully produced with 30% fly ash replacement.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.655-660
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• 2002

The purpose of this study is to analyze void ratio, coefficient of water permeability, and strength characteristics when silica fume and carbon fibers were added in order to improve the strength of porous concrete, and when recycled aggregates were used. Comparing with the case that recycled aggregate was not used, as the replacement ratio of recycled aggregate increased, the differences in void ratios and strength characteristics were decreased. In the case that silica fume was used, the content of 10% silica fume was most effective in improving strength. In the case that carbon fibers were used, the content of 3% carbon fiber were good to achieve the highest flexural strength, and Pan-derived CF was much better than pitch-derived CF in improving these effects.

• Geomechanics and Engineering
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• 제10권1호
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• pp.95-107
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• 2016

Deep soil mixing with cement and cement-lime mixtures has been widely used for decades to improve the strength of soils. In this study, small-scale laboratory model tests of polymer columns in soft clayey soil were conducted to evaluate the feasibility of using various polymeric compounds as binders in deep soil mixing. Floating and end bearing polymer columns were used to examine the load-settlement relationship of improved soft clayey soils for various area replacement ratios. The results indicate that polymer columns show good promise for use in deep mixing applications.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1030-1035
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• 2008

Dynamic numerical analyses were performed to investigate the response of liquefaction remediation of rammed aggregate piers(RAP) on soft ground under free strain conditions. The safe factors of the soft ground reinforced by RAP during seismic loading of magnitude 6.5 were calculated. The results of simulation showed that factors of safety were affected various area replacement ratios, surcharge loads and depth of RAP systems.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.423-426
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• 2005

Until now, the quantity to recycle wasted concrete as the great supplementary value was very little. But considering a insufficiency of the present state of aggregates, the recycling of wasted aggregates is indispensable. Recycled aggregate is useful resources for concrete, but its application to structural member is not frequently. In this an experimental study here in, this study is to reinforcement orientation containing fiber of the spun-concrete using recycled aggregate, evaluation of designed chlorine-ion and carbonation resistance. The result of study chlorine-ion resistance by using replacement ratios ($0.00\%,\;0.01\%,\;0.03\%,\;0.05\%,\;0.08\%$) of fiber which it more increase. Carbonated thickness of the spun-concrete used fiber and the normal spun-concrete was similar or it appeared with the tendency which it diminishes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.5-8
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• 2006

In this study, various fundamental experiments including durability and time-dependent deformation are performed to compile a database for a utilization of high-strength concrete for PSC bridges. In the mix design, concrete strength at early age when prestressing forces are introduced to the PSC member and slumpflow suitable for pumping of concrete are considered to make a concrete fit for PSC bridges. The main parameters investigated are the kinds and replacement ratios of mineral admixtures and low-heat cement. Experimental tests on durability include penetration of chloride ions, freezing-thawing, combined deterioration, and simple adiabatic temperature rise test. In addition, time-dependent deformation such as creep, drying and autogenous shrinkage, which is particularly important factor in the design and construction of PSC bridges, is tested and analyzed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.161-164
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• 2006

The main objective of this study was to evaluated the physical properties of concrete with substitution ratio of recycled fine aggregate and recycled coarse aggregate made of waste concrete. The replacement ratios of recycled coarse and fine aggregate decided 0%, 30%, 40% and 50% respectively to get the deregulate of floor space Index. The test result showed that compression strength of cylinder mold decrease with the substitution ratio increase but its strength of replaced recycled fine aggregate higher than OPC.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.57-58
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• 2009

기존연구 결과에 의하면 순환굵은골재 콘크리트를 사용한 경우와 순환잔골재 콘크리트를 사용했을 경우 모두에서 구조부재의 내력저하는 나타나지 않고 천연골재와 동등한 성능을 나타내었다. 이러한 연구결과를 바탕으로 순환굵은골재와 순환잔골재를 혼합 사용한 실물부재 콘크리트보에서 역학적 성능평가를 목적으로 하고 있다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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• pp.73-76
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• 2010

This study deals with the properties of polymer-modified mortars with a nitrite-type hydrocalumite, which are effectively used as intelligent patch materials for deteriorated reinforced concrete structures. The calumite is a material that can adsorb the chloride ions (Cl-) causing the corrosion of reinforcing bars and liberate the nitrite ions (NO2-) inhibiting the corrosion in reinforced concrete, and can provide a self-corrosion inhibition function to the reinforced concrete. Polymer-modified mortars using hydrocalumite and terpolymer powders are prepared with various calumite contents and polymer-binder ratios, and tested for corrosion inhibition. Subsequently, regardless of the polymer-binder ratio, the replacement of ordinary portland cement with the calumite has a marked effect on the corrosion-inhibiting property of the polymer-modified mortars.

• International Journal of Concrete Structures and Materials
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• 제3권2호
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• pp.91-95
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• 2009

Reclaimed asphalt pavement (RAP) is abundant substitute for natural aggregate in many areas. It is obtained by crushing of old road pavements in milling machine during rehabilitation and reconstruction process. In this study, reclaimed asphalt pavement mortars (RAPM) have been produced with different cement dosages and replacement ratios. The destructive and nondestructive tests have been conducted on specimens to determine physical and mechanical properties of RAPM. The free and restrained shrinkage tests on RAPM have been conducted to predict fractural behavior of mortars. The aim of the shrinkage tests was to delay crack formation and improve strain capacity of mortars before cracking. The results showed that RAPM exhibits lower elasticity modulus; however the tensile capacity was improved for deformation before cracking.