• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.217-225
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• 1998

분쇄한 FRP(Fiver-Reinforced Plastics) 폐기물을 사용한 폴리머 모르타르의 물성에 고나하여 조사하였다. 분쇄한 FRP 폐기물을 시멘트 모르타르의 세골재로 재활용하기 위하여 세골재에 대하여 0~50wt% 치환.사용하였고, FRP 폐기물의 사용으로 나타나는 강도 저하현상을 보완하기 위하여 3종류 폴리머 혼화제의 첨가량을 변화시켜 각종 공시체를 제작하였다. 폴리머 혼화제로서는 styrene-bytadiene rubber(SBR) 라텍스, polyacrylic ester(PAE) 에멀젼 및 ethylene-vinyl acetate(EVA)에멀젼을 사용하였다. 분쇄한 FRP 폐기물을 사용한 시멘트 모르타르에 폴리머 혼화제를 첨가하여 만든 폴리머 시멘트 모르타르는 폴리머 혼화제를 첨가하지 않은 모르타르보다 압축 및 휨강도가 크게 증가하였다. 폴리머 시멘트비 10wt%에서 세골재 대용으로 분쇄한 FRP 폐기물의 적정 치환량은 20wt%로 나타났다. 8$0^{\circ}C$에서 가열양생하여 제조한 폴리머 시멘트 모르타르는 폴리머 시멘트비 10wt%이하에서 표준양생한 모르타르보다 강도가 저하되었다. 폴리머 시멘트 포르타르의 흡수율은 폴리머 시멘트비가 증가함에 따라 크게 감소하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.685-688
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• 2008

This study has examined the effect of bottom ash(BA) on the properties of low heat-blended cement(LHC) and concrete. A number of binders were prepared by the replacement of LHC with BA in range of 5$^{\sim}$20wt%. The results showed that the final setting time of cement paste were delayed when the BA replaced part of the cement. However, The heat of hydration increased narrowly with adding BA in a early hydration period. The results also showed the inclusion of BA at replacement levels of 5$^{\sim}$10wt% resulted in an increase in compressive strength of the specimens compared with that of the control concrete and improved a resistance of concrete against the sulfate and chlorine ion.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.23-28
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• 1999

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.269-270
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• 2009

As manufacturing the Precast Concrete simulation structure, we generally investigated the strength characteristic of the concrete according to diversity of the cement and heat curing condition respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.251-252
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• 2009

Rheological characteristics of flowable concrete manufactured in domestic products of cement, aggregates, and SP admixtures were investigated by experiments and the predictive model of rheological characteristics of flowable concrete has been newly proposed considering with the effects of the W/C ratio and the dosage of SP admixture.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.219-220
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• 2010

This study investigated endurance properties of marin concrete corresponding to various W/B ratio and cement to develop long-life-time marin concrete insured durability.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.56-62
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• 2012

The results presented in this paper form part of an investigation into the optimization of a ternary blended cementitious system based on ordinary Portland cement (OPC)/blast furnace slag(BFS)/fly ash(FA) for the development of ultra high strength concrete. Concrete covering a wide range of BFS/FA blending proportions were investigated. Compressive strength at the ages of 3, 7 and 28 days for concrete specimens containing 0%, 10%, 20% and 30%FA along with 0%, 30%, 40% and 50%BFS as partial cement replacement at a water-binder ratio of 0.18 were investigated. Tests on porosity and pore size distribution were conducted using mercury intrusion porosimetry. The results show that the combination of FA10 and BFS30 can improve both short- and long-term properties of concrete as results of reducing of pores larger than 50nm.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.365-368
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• 2008

This research is related to 240MPa ultra-high strength concrete(UHSC) with extremely loss W/B ratio. For this development, High flow cement is mainly used which has a short reaction rate due to the high blaine and high early strength, which can make greater fluidity in case of very low W/C ratio. It made the best mixture using the mineral admixtures silica fume, slag powder and special admixture. For dispersibility and homogeneity of cement binder, cement of premix type is produced using omni-mixer. Moreover, it ensures the fluidity of ultra-high strength concrete(UHSC). For having a good fire performance, we made an experiment special coarse aggregate. As a result, we got 180MPa in case of water curing, 200MPa in case of steam curing and uniform UHSC of 240MPa in case of a special curing method.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.2
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• pp.132-139
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• 2015

In this study, the different unit cement content by the ratio of water absorption and water-cement ratio are applied to examine the properties of the concrete used the aggregate recycled by the crushing treatment. According to the experimental results, in the mix of low strength and high water-cement ratio, both of the compressive strength is almost equal in the concrete using the recycled aggregate by the crushing treatment and the concrete using broken stones. It means that the recycled aggregate has the low effect of the amount of bonded mortar. But, in the mix of high strength and low water-cement ratio, the concrete using the recycled aggregate by the crushing treatment has 40% less of the compressive strength than that using broken stones by the effect of the amount of bonded mortar. On the other hand, after 8 weeks, the dry shrinkage of the recycled aggregate with 7% of the ratio of water absorption doubles that of the broken stones with 1% ($-350{\times}10^{-6}$), in other words $-700{\times}10^{-6}$. Thus, the dry shrinkage should be prior to any other conditions in recycling waste concrete for the aggregate for concrete. When the recycled aggregate with 3% of the ratio of water absorption is used, the compressive strength of the rich mix concrete ($450kg/m^3$ of the unit cement content) is equivalent to that of the concrete using broken stones, while in using the recycled aggregate with 7% of the ratio of water absorption, the rich mix concrete has 7% lower compressive strength than the concrete using broken stones. But, the compressive strength of the ordinary mix concrete ($350kg/m^3$ of the unit cement content) is far lower than that using broken stones.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.487-493
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• 2008

Tunnel structures are widely used for transportations in mountains areas. To shorten the construction period and to cut down the construction expenditure, a construction technique that a tunnel excavation process and a tunnel lining process are simultaneously performed is often applied in the field. However, due to the vibration and impact caused by excavation process, cracking and deterioration of tunnel lining concrete could happen. This research experimentally investigated the effective role of the usages of blended cement and recently developed nylon fibers for tunnel lining concrete. It has been observed that both nylon fibers and blended cement improve the durability and physical properties of concrete.