• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.112-116
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• 1996

This experimental study was performed to produce high flowing nomal strength concrete using viscosity agent. Test variables were selected to the viscosity agent contents with 4 levels, the cement contents with 5 levels and the coarse aggregate contents with 3 levels, etc. As a result, the high flowing and filling properties of concrete were obtatined by proper amount of viscosity agent and superplasticizer in the normal strength concrete. For the concrete mix proportions, it was found that unit weight of cement was more than 364kg/㎥ and volume of coarse aggregate was less than $280\ell/\textrm{m}^3$ in this study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.266-270
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• 1996

The objective of this study is to develop the Non-compacting concrete with mormal strength in practice by using viscosity agent and flyash. In this paper, we present the reference data about not only the properties of Non-compacting concrete at fresh state such as flowability, segregation-resistibility, placebility and so on but, optimum mixing design using viscosity agent and flyash. The test results indicate that optimum dosage of viscosity agent in combination of flyash in 50% of W/C is about 400g/$\textrm{m}^3$ with 20% of the ratio of flyash replacement.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.369-372
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• 2008

본 연구에서는 소요의 유동성능 및 공기량을 확보할 수 있는 병용계 보통강도 고유동 자기충전 콘크리트를 제조하기 위하여 증점제 및 소포제 첨가량를 변화시킨 병용계 고유동 자기충전 콘크리트의 유동 특성을 실험적으로 분석 고찰하였다. 실험결과 증점제를 첨가한 병용계 고유동 자기충전 콘크리트의 Slump flow는 증점제 첨가량이 0.2%(${\times}$W %)일 때 가장 증가하였으며 증점제 첨가량이 높아질 경우 JSCE 기준안(2등급)에서 제시한 V-funnel의 유하시간 규정값을 크게 벗어나는 결과가 나타났다. 또한 증점제, 소포제 및 AE제를 첨가한 배합을 제외한 모든 배합이 목표 공기량 $4.5{\pm}1.5%$를 만족하지 못하였으며, 소포제를 첨가한 병용계 고유동 자기충전 콘크리트 배합은 최초배합 후 시간의 경과에도 불구하고 공기량(A1=1.5%)이 다소 감소하는 결과가 나타났다. 이러한 결과를 통하여 병용계 고유동 자기충전 콘크리트 제조시 소요의 유동성능을 얻기 위한 최적의 혼화제량을 알 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제4권3호
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• pp.177-184
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• 2000

The purpose of this study is to evaluate the performance of a new viscosity modifying admixture for concrete agent. For this purpose, selected test variables were the ratio of water to cement, the ratio of cement to fine aggregate, contents of superplasticizer, contents of viscosity modifying admixture. As a result of this study, it has been found that addition of viscosity modifying admixture to mortar modfies its fluidity and reduces its segregation by increasing the mortar viscosity. And it has been found that a new viscosity modifying admixture do not significantly affect the setting time, air content of mortar.

• 콘크리트학회논문집
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• 제11권4호
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• pp.95-105
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• 1999

When superplasticizer is added to manufacture flowing concrete, the base concrete usually needs the adjustment to assure the sufficient fines contained to obtain flowable consistency without excessive bleeding or segregation. However, this may not only increase the cost, but also cause inconvenience in producing the base concrete. In this paper, the experiments are performed on normal base concrete to achieve a segregation-reducing flowing concrete by adding superplasticizer mixed with viscosity agents and AE admixtures. Three kinds of superplasticizer and two kinds of viscosity agent are selected. According to the results, with regard to the performance and cost of the admixtures, melamine type superplasticizer combined with the PEO viscosity agent and AE admixtures at the ratio 1:0.28:0.001 can acquire good quality and reduce the cost in producing the flowing concrete. With proper addition of combined superplasticizer, even though water to cement ratios of the base concrete are different, the segregation-reducing flowing concrete could be also achieved without reproportioning of the base concrete. However, it would be more desirable if the superplasticizer could be adjusted, before it is put into the practical use in order not to cause some other problems, such as rapid rate of slump loss and retarding of setting time.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.689-696
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• 2017

기존의 고유동 콘크리트는 높은 분체계로 인해 수화열과 수축의 증대, 비경제적인 강도발현 등의 문제점이 발생하여 일반강도 범위의 콘크리트에는 사용범위가 제한하고 있다. 그러나 공사품질의 향상과 더불어 공사비 절감, 공기단축 등의 이점으로 일반강도 수준의 고유동 콘크리트의 필요성이 대두되고 있다. 이를 위해 본 연구에서는 점성을 최소화하고 재료분리 저항성은 극대화 된 저분체 고유동 콘크리트를 제조하기 위하여 적절한 증점제의 사용방법과 최적 배합을 검토하고 제조 된 콘크리트의 특성을 검토하였다. 다양한 증점제를 대상으로 역학적 특성 평가를 통해 저분체 고유동 콘크리트 제조에 적합한 증점제를 선정하였으며, 그 결과 아크릴계(Acrylic. 이하 AC) 및 우레탄계(Urethane, 이하 UT) 증점제가 재료분리가 발생 하지 않는 범위에서 가장 우수한 성능을 나타내어 가장 적합한 것으로 나타났다. 선정된 AC 및 UT 증점제의 최적 혼입량을 검토하기 위하여 두 물질의 혼합사용 및 고성능 감수제와 일액화를 통한 배합실험을 하였으며, 그 결과 AC 및 UT 증점제의 비율이 5:5인 경우 유동성 증대 및 점성 저감 효과가 증가함에 따라 저분체 고유동 콘크리트에 가장 적합한 것으로 나타났다.

• 한국주조공학회지
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• 제30권6호
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• pp.241-246
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• 2010

The viscosity of foam metal is necessary to get the pores, but it is difficult to manufacture net-shape foam, because the fluidity decreases by increasing viscosity. In this study, the A356 alloy which has good fluidity and less defect was selected and fabricated to foam metal. To understand about effect of thickening agent on foaming and mechanical properties, quantity of thickening agent was changed. The pore size, porosity and distribution of foam metal were measured by i-solution program. And compression test were performed by UTM. In case of 3.0wt% Ca in thickening agent, it is found that most of foam consist of homogeneous shape, and the growth height had the highest value of 204 mm in the all fabricated foams. The porosity was 93% and compressive strength was 3.1 MPa. In the microstructure, the $Al_2Si_2Ca$ intermetallic compound and Ti were observed. The vickers hardness value rose with increasing viscosity value.

• 펄프종이기술
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• 제44권2호
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• pp.67-73
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• 2012

Structural stability and shock absorption are important properties for corrugated board. In order to maintain structural stability, adhesive properties between top/bottom liners and corrugated medium are not only essential but also important for productivity and product quality. Borax has been an essential ingredient in corrugating adhesive solution. Borax increases viscosity, bonding between starchs and green adhesive bond. The objective of this research is to improving adhesive strength and viscosity stability by adding cross-linking agent instead of borax. Rheology and penetration of main starch gelatinization slurry were affected by borax addition level. Borax increased viscosity and decreased viscosity stability, while cross-linking additives increased viscosity stability and adhesive strength by anchoring effect.

• 콘크리트학회논문집
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• 제14권3호
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• pp.275-282
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• 2002

고유동 콘크리트를 제조할 경우는 유동성 향상을 위한 다량의 고성능 감수제와 재료분리를 방지하기 위한 다량의 분체 혹은 증점제로 말미암아 제조비용이 고가이고, 또한 품질관리에도 많은 어려움이 있다. 그러므로, 본 연구에서는 유동성 및 재료분리 저항성이 우수한 고유동 콘크리트를 경제적으로 제조하기 위하여 분리저감형 유동화제의 최적배합비를 결정한 다음, 유동화 공법으로 접근하는 것을 검토하였다. 실험결과로 유동화제 첨가량이 증가할수록 유동성 및 블리딩량은 증가하였고, 공기량 및 재료분리저항성은 저하하는 것으로 나타났다. 따라서, 여기에 증점제를 첨가함에 따라 양호한 유동성에서 블리딩량이 저하하였고, 재료분리저항성도 증대되었는데, 마지막으로 AE제량 증가에 따라 저하된 공기량이 회복되므로써 양질의 분리저감형 유동화제로 최적배합비를 결정할 수 있었다. 경화 콘크리트 특성으로 유동화 공법으로 제조된 고유동 콘크리트의 압축강도는 베이스 콘크리트보다 증가하는 것으로 나타났고, 무다짐 공시체의 압축강도는 표준다짐 공시체의 압축강도와 유사한 것으로 나타나 다짐 방법간의 차이는 없는 것으로 나타났다.

• Macromolecular Research
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• 제16권3호
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• pp.218-223
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• 2008

In order to obtain crosslinked poly(butylene succinate) (PBS) foams with a closed-cell structure, a commercial-grade PBS was first modified in the melt using two different branching agents to increase the melt viscosity. The rheological properties of the branched and crosslinked PBS were examined by varying the amount of the branching agents. The complex viscosity of the crosslinked PBS increased with increasing amount of the branching agent. However, it decreased with increasing frequency. When 2 phr of the branching agent was added to PBS, the storage modulus (G') was higher than the loss modulus (G") throughout the entire frequency range, showing that the addition of a branching agent increases the melt viscosity and elasticity of PBS effectively. Closed-cell PBS foams were prepared by mixing the chemical blowing agent with the crosslinked PBS. The effect of the foaming conditions such as temperature and time, and the amount of the crosslinking agent on the structure of the expanded PBS foams were also investigated.