• Cement
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• s.191
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• pp.43-48
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• 2011

최근 고강도화 기술이 발전함에 따라 각국에서는 지역마다 랜드마크로 불리는 건축물들이 자주 등장하는 것을 문헌을 통하여 자주 접한다. 또한 건축물의 거대화 고층화에 따라, 합리적인 설계를 가능하게 하는 콘크리트의 경량화가 새로운 과제로 주목을 받고 있다. 초경량 콘크리트 구조물을 실용화 할 수 있으면 상부구조의 경량화, 지진하중의 저감, 건설기계의 생력화, 기초 부담의 저감 및 기초의 경량화 등에 따라 건설콘스트 에너지 전체의 저감에도 큰 효과가 기대되기 때문이다. 국내에도 경량 골재에 대한 제조가 간헐적으로 계속되어 오고 있다. 특징을 보면 산업부산물을 이용한 친환경소재, 에너지 절감, 흡수율 등을 대폭적으로 낮추었다고 소개되고 있는 반면, 비중을 초경량화한 경우는 거의 없다. 따라서 본 검토는 절건비중이 1.0 미만인 초경량골재를 사용한 경우로 비록 실험실적 결과이지만 쉽게 접할 수 있는 제품이 아닌 것 같아 아소(麻生)공과대학 미즈다(水田)교수의 논문을 소개하는 것이고, 콘크리트 테크노 2009년 1월에 게재된 문헌을 요약 발췌한 것임을 밝혀둔다.

• Magazine of the Korea Concrete Institute
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• v.23 no.5
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• pp.18-26
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• 2011

• Magazine of the Korea Concrete Institute
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• v.23 no.5
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• pp.27-32
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• 2011

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.743-748
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• 2006

This paper presents results of an experimental study conducted to investigate the effect of volume fraction of fibers on the mechanical properties of a fiber-reinforced, lightweight aggregate concrete(FRLAC) that was produced without an autoclave process. The FRLAC enhanced the strength of lightweight, cellular concrete by adding polypropylene fibers and lightweight aggregates. To investigate the effect of volume fraction of fibers on the mechanical behavior of FRLAC and to determine the optimal volume fraction of fibers, a series of compression and flexural strength tests on FRLAC specimens with various fiber volume fractions(0%, 0.10%, 0.25%, 0.50%) were conducted. It was observed from the tests that a 0.25% volume fraction of fibers maximized the increase in the strength of FRLAC and the fibers controlled cracking in FRLAC.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.449-455
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• 2022

Concrete is the most widely used construction material. The heavy self-weight of concrete may offer an advantage when developing high compressive strength and good dimensional stability. However, it is limited in the construction of super-long bridges or very high skyscrapers owing to the substantially increased self-weight of the structure. For developing lightweight concrete, various lightweight aggregates have typically been utilized. However, due to the porous characteristics of lightweight aggregates, the strength at the composite level is generally decreased. To overcome this intrinsic limitation, this study aims to develop a construction material that satisfies both lightweight and high strength requirements. The developed cementitious composite was manufactured based on a high volume usage of hollow glass microspheres in a matrix with a low water-to-cement ratio. Regardless of the tested hollow glass microspheres from among four different types, compressive strength outcomes of more than 60 MPa and 80 MPa with a density of 1.7 g/cm³ were experimentally confirmed under ambient and high-temperature curing, respectively.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.751-757
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• 2004

Artificial lightweight aggregates and solids were manufactured with coal ash(fly ash, bottom ash). In order to apply alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate to concrete, several experimental studies were performed. Thus, it can be noticed the optimal mix proportion, basic characteristies, mechanical properties and environmental safety of alkali-activated coal ash(fly ash, bottom ash) solid and alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate. Also, the freezing-thawing test property of concrete using the alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate was investigated. As a result, the optimal mixing proportion of coal ash(fly ash, bottom ash) solid to make alkali-activated artificial lightweight aggregates was cement $10\%$, water glass $15\%$, NaOH $10\%$, $MnO_2\;5\%$. Alkali-activated coal ash(fly ash, bottom ash) solid can achieve compressive strength of 36.4 MPa, at 7-days, after the paste was cured at air curing after moist curing during 24 hours in $50^{\circ}C$. Alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate that do impregnation to polymer was improved $10\%$ crushing strength $150\%$, and was available to concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.489-490
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• 2009

In this study, the experiment was carried out to investigate the effect of metakaolin on the compressive strength of lightweight aggregate cellular concrete. For this purpose, five level replacement ratio of metakaolin were selected.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.381-384
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• 2008

The artificial lightweight aggregate was manufactured using stone-dust(SD) and bottom ash(BA) from crushed aggregate manufacture process and thermoelectric power plant respectively. The properties of artificial lightweight aggregate according to mixing ratio of SD and BA was that the density was decreased and the absorption was increased with increasing BA content, because bottom ash was contained many unburned carbon and $Fe_2O_3$ which generates gas by oxidation during a sintering process. The appropriate mixing ratio of SD and BA was estimated at about 5:5. The properties of artificial lightweight aggregate according to addition flux admixture was that it had lower density with increasing of $Na_2SO_4$ content. In this study, we could developed the artificial lightweight aggregate as the bulk density was $1.52g/cm^3$ and water absorption 7.3% under the condition that mixing ratio of SD:BA was 5:5, $Na_2SO_4$, $Fe_2O_3$ 1%, sintering temperature $1,150^{\circ}C$ and sintering time 15mins.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.159-169
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• 2010

A multiphysics model analysis including moisture transport, heat transfer and solid mechanics and experiments on the normal and light weight concrete were carried out in order to study the effect of preabsorbed water in the light weight aggregates on the drying and shrinkage characteristics of concrete. Consequently, with fixed water-cement ratio, loss of water content of normal and light weight concrete were compared and the results showed that the lightweight concrete lost less moist than the normal concrete in early age and long term which was by moist supply effect. Accordingly, shrinkage strain size and distribution of lightweight concrete were decreased, and shrinkage reducing effect was efficient in early age with water cement ratio 0.3 and in both early age, and long term with water cement ratio 0.5. The comparison of analysis results and exaperimental results indicate that characteristic values of moisture transport and the relation humidity and shrinkage strain from this study are resonable for application for other differential shrinkage analysis in lightweight concrete.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.498-500
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• 2007