• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.608-614
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• 2002

The effects of slag content and polymer-binder ratio on the strength properties of autoclaved SBR-modified concretes using ground granulated blast-furnace slag(slag) and a styrene-butadiene rubber (SBR) latex are examined. As a result, the compressive and tensile strengths of the autoclaved SBR-modified concretes using slag increase with increasing slag content, and reach a maximum at a slag content 40％, and increase with increasing polymer-binder ratio. In particular, the autoclaved SBR-modified concretes with a slag content of 40％ provide about three times higher tensile strength than unmodified concretes. Such high strength development is attributed to the high tensile strength of SBR polymer and the improved bond between cement hydrates and aggregates because of the addition of SBR latex.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.92-99
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• 2002

This paper is Intended to investigate physical properties and surface glossing of exposed concrete incorporating granulated blast furnace slag(BS). According to test results there is no remarkable variations in fluidity and air content with increase of BS, but unit weight shows decline tendency Compressive strength at later age gains considerably due to potential hydraulicity reaction of BS. It shows that drying shrinkage increases. It is found that low W/B, surface coating and high BS content lead to favorable effects on the surface glossing of exposed concrete because of filling effects on the voids of the concrete. It is improved by about 7 ％ with increase every 10 ％ of BS content. The effects of form pannel kinds on the improvement of surface glossing are in order for acryl, fancy, steel and wood.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.5-15
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• 2011

In this study, centrifuge model tests were performed to investigate stress concentration ratio, stress characteristics of soft clay ground improved by granular compaction piles with changes of piles type, loading condition and area replacement ratio. From the results of rigid loading tests, while vertical stresses acting on clay ground is similar, vertical stresses acting on GCP is larger than those acting on SCP with same replacement ratio. Also, average stress concentration ratio is increased proportionally with increasing the area replacement ratio of GCP and SCP. It was evaluated that average stress concentration ratio of soft clay ground improved by GCP is larger than that of SCP. As a result of flexible loading tests, stress concentration ratio is the highest when replacement ratio of GCP and SCP is 40%. Average stress concentration ratio of soft clay ground improved by GCP is a little more higher than is improved by SCP.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.33-38
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• 2011

Presently, domestic SCP method with low replacement ratio is required as alternative in order to overcome the profitability of the sand resource because of the deficiency phenomenon of the sand resource by the actual condition design and construction is made by SCP method with low replacement ratio more than 70% for the port construction in the safe side. Sand compaction pile(SCP) method has been mainly used to improve the properties of soft clay or loose sandy ground. In design of SCP at soft clay ground, it is very important to determine the stress concentration ratio of composite ground relevant to the area replacement ratio. In this study, 2-dimensional FEM analyses were carried out to evaluate the stress concentration ratio of composite ground depending upon the area replacement ratio. When the interpretation result replacement ratio was 30%, the stress assigned rate showed and as the replacement ratio was high, the stress assigned rate according to the sinkage showed the low stress assigned rate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.89-96
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• 2011

In this study, increasing the range of replacement rate of FA with concrete properties were analyzed to provide basic data of FA replacement 0-40 % and curing temperature $5-35^{\circ}C$ range. As a result of the increased fluidity in proportion to the increase in FA, but decreased air. Setting time delayed at replacement rate increases and low temperature, simple insulation temperature history of the FA up to 40 % replacement rate increases the maximum temperature was low $8^{\circ}C$, the highest temperature reaching time delay of 13 hours. FA replacement up stream of the curing temperature, compressive strength compared to the higher plane, it was found that improved strength development. In carbonation tests with increasing the replacement ratio of FA carbonation depth was increased. Therefore, continued research on carbonation measures was to be necessary.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.9-15
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• 2023

The cement is a typical CO₂ emission industry. Manufacturing process improvements and increased use of alternative materials are needed to reduce energy consumption and CO₂ emissions. This study confirmed the basic characteristics of cement hydration by sintering CAF at low temperature as a CO₂ adsorbent material. For the hydration product of the synthetic CAF, crystal phase analysis, porosity, and structural images were confirmed, and the compressive strength was measured. The replacement rate of SCAF was 10, 20, and 100 %, and the compressive strength tended to decrease as the replacement rate increased. In addition, when the SCAF substitution rate is 100 %, the hydration products of the early age are calcium aluminum oxide hydrate (Ca₃Al₂O₆ x H₂O) and calcium iron hydroxide (Ca₃Fe(OH)₁₂), and at substitution rates of 10 and 20 %, CAF compounds other than general cement hydrates brownmillerite was observed. As for the porosity, the pore size increased and the porosity increased with the increase of the replacement ratio. As a result of this study, CAF manufactured by low-temperature sintering seems to be difficult to use alone and general curing for utilization as a CO₂ adsorbing material.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.282-290
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• 2013

In this study, the adjustment range of mixture factor with replacement mineral admixture was reviewed to secure the mixture change data of high volume concrete compared to general concrete. When changing the concrete mix to high volume concrete within the universal concrete mixing, the adjustment range of mixture to ensure optimum quality is as follows. Unit-water content is $20{\sim}30kg/m^3$ downward. Fine aggregate ratio dropped by approximately 1% when W/B was reduced by 5%, and it is reduced by approximately 0.12% when there is a 5% increase in the total replacement rate. When the FA replacement rate was increased by 5%, the AE agent was approximately 20% to 30% higher compared with the conventional one. When the FA and BS replacement rate rose by 5%, W/B was reduced by about 1 to 4%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.105-110
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• 2009

It's important to study about suitable substitutional material of expensive silica fume because it used widely for silica fume as a high-strength mortar binding agent. The main purpose of this study is to check which is the most efficient binder for the expensive silica fume's alternative material. And this study also present basic data about to make high-strength mortar when we use alternative material instead of silica fume through research outcome. Also writers analzed flow properties respectively, so it was founded out the substitutional goods fare like meta-kaolin, HMBA which are less expensive than silica fume because they are in domestic enough.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.889-892
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• 2008

This study, having combined and displaced fly ash known as admixture material that delays hydration reaction with coarse particle cement("CC" hereinafter) collected in particle classification method during ordinary portland cement("OPC" hereinafter), reviewed the hydration heat characteristics affecting the concrete. To reduce hydration heat, the study plain-mixed which used 100% OPC for WB 50% level 1, displaced CC at level 3 of 25%, 50% and 75% for OPC, and by displacing FA with admixture material at level 5 of 0%, 10%, 20%, 30% and 40%, experimented totally 16 batches. As a result of experiment, in the case of flow, the more CC displacement rate increased, the more it tended to decrease, and the more FA displacement rate increased, the more it decreased. As for simple adiabatic temperature rise by the CC and FA displacement rates, it decreased as displacement rate increased, and particularly in the case of FA40, temperature rise amount, $5.8{\sim}7.4^{\circ}C$, was very low. Compressive strength decreased in proportion to displacement rate, however strength reduction increment was shown to decrease with age progress.

• Magazine of the Korea Concrete Institute
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• v.10 no.3
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• pp.135-142
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• 1998

본 연구는 초유동 콘크리트용 모르타르의 물/결합재비 및 고성능 감수제 첨가율에 따른 상대플로우 면적비와 상대깔대기 속도비의 상관관계를 실험으로 검토한 것이다. 구속수비 실험결과, C급 플라이애쉬>F급 플라이애쉬 > 석회석분순으로 나타났기 때문에 F급 플라이애쉬 및 석회석분은 유동성 개선에 효과적인 것으로 나타났다. 또한 모르타르 실험결과, 상대플로우 면적비와 상대깔대기 속도비는 고성능 감수제 첨가율이 일정할 경우 물/결합재비의 변화에 따라 원점을 지나는 직선관계로 나타났지만, 물/결합재비가 일정할 경우에는 고성능 감수제 첨가율의 변화에 따라 원점을 지나는 곡선관계로 나타났다. 따라서, 수식화 모델은 Rm= A. m0.4가 합리적이며, 최적값인 ( m .Rm)=(5.1)을 만족하는 배합조건은 플라이애쉬의 경우 치환율 30%, 물/결합재비 83%이며, 석회분의 경우 치환율30%, 물/결합재비 77%로 판명되었다.