• 한국건축시공학회지
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• 제6권3호
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• pp.75-82
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• 2006

This study investigates the influence of various blending factors on cement paste fluidity and find out the most effective evaluation method of cement paste flow, comparing flow test apparatuses such as ring flow(R-F), flow cone(F-C) and mini slump(M-S). A viscometer also measures the rheology coefficients to secure faithful numerical data. Firstly, series I examines cement paste, affected by several cement products and mineral admixture types in the range of W/B 40%, ordinary fluidity, and W/B 30%, high fluidity. In this series, the three types of cement product depended on companies, are randomly used and the mineral admixture, such as fly ash, blast furnace slag and silica fume, are incorporated in the cement paste, in response to the ratio of 10, 20, to 30%, respectively. In addition, series II studies various chemical admixture types, affecting the cement paste. This series is carried out with manufacturing companies and component types in the range of W/C 30%, high fluidity. For the manufacturing companies, randomly four products are used and for the component types, polycaboxylate, melamine, naphthalene and lignosulfonate type are chosen. Test results showed that in the fluidity test of cement paste considering various types of blending factors, R-F exhibited similar tendency with F-C and M-S. In the analysis of consistency curves measured by viscometer, the fluidity evaluation method using flow test apparatuses was significantly effective, except for the some of the low fluidity specimens. In conclusion of this study, R-F was the most convenient, faithful and effective fluidity evaluation method of cement paste.

• 한국디지털건축인테리어학회논문집
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• 제12권4호
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• pp.87-95
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• 2012

Autoclaved lightweight concrete (ALC), also known as autoclaved aerated concrete (AAC), is a lightweight, precast building material that simultaneously provides structure, insulation. ALC is a unique building material. Because of its cellular nature, it is lightweight, self-insulating, as well as sound and fireproof. ALC products include blocks, wall panels, floor and roof panels, and lintels. Recently, the use of ALC has became increasingly popular. However, ALC have high water absorption, low compressive strength and popout the origin of the low surface strength in its properties. Thus, this study is to improve the fundamental strength by controls of increasing of admixtures and chemical reactants. Admixtures make use of meta kaolin and silica fume, chemical reactants make use of sodium silicate and sodium hydroxide. From the test result, the ALC using admixtures and chemical reactants have a good fundamental properties compared with plain ALC. These good fundamental properties is caused by the admixtures and chemical reactants of ALC by the reason of the micro filling effect and chemical binding of C-S-H gel, tobermolite and quartz.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.103-106
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• 1999

In this study, the properties of mortar using ceramic wastes as admixtures and fine aggregates are considered experimentally. The main chemical of ceramic wastes is SiO2 and micro structure of ceramic wastes is porous. Absorption of ceramic wastes is higher than that of river sand and specific gravity is lower than that of river sand. Flow value of mortar using ceramic waste admixture and fine aggregates is increased more or less and the strength of mortar using ceramic wastes as fine aggregates is increased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.441-442
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• 2009

Concrete has some self-healing ability if the crack is occurred. Concrete with a inorganic-organic chemical compound, self-healing ability is increased at the surface of the crack. In this study, we investigate self-healing performance of concrete using admixutre by performing permeability test.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.95-98
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• 2003

Waste lime is produced as by-products in chemical industry, Reuse of waste lime mixed with soil for banking and backfill material in civil works was analysed in this study. For this purpose, environmental effect of waste lime admixtures was tested. Thus, this study presents the leaching characterization of waste lime in laboratory batch and column tests. Countermeasure for reduction of environmental effects was suggested from the test results.

• 한국응용과학기술학회지
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• 제14권2호
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• pp.103-114
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• 1997

Metachromatic properties of admixture of methylene blue(MB) and thionine in aqueous solution has been studied by fluorescence spectroscopy. In spite of nonfluorescence character has been MB itself, mixing MB to monomeric concentration of thionine, new coaggregation band has been formed in shorter wave length than fluorescence of thionine because of MB was redistributed to thionine aggregate. It suggested that coaggregate of MB and thionine were more tightly formed than the each dye aggregate.

• 한국농공학회지
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• 제45권3호
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• pp.41-49
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• 2003

In this study, durability performance of blended cement mortars is evaluated when various mineral admixtures are used with the cement. A comprehensive evaluation of the effects of mineral admixtures on the mortar performance was made. The properties of fresh and hardened blended mortars investigated include slump flow and compressive strength. The durability characteristics of cement materials incorporating the mineral admixtures under various physical and chemical causes of deterioration was investigated. The laboratory test results indicate that mechanical and durability properties of blended cement mortars have superior performance rather than ordinary cement mortars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.140-145
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• 1991

Tests were conducted to get a mix proportioning of high strength concrete between σ28 and (C/W) using low quality materials easily purchased in situ. Superplasticizer was used as a chemical admixture to compensate low slump of base concrete keeping it up about 15±2㎝. General material properties such as modulus of elasticity, poisson's ratio, unit weight and stress-strain characteristic of high strength concrete were obtained. Test results show that mix proportioning of high strength concrete proposed in this paper have reasonable validity and these can be used as a design criteria in high strength concrete construction.

• 대한토목학회논문집
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• 제14권4호
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• pp.721-728
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• 1994

본 연구는 국내 제철소에서 산업부산물로 발생되는 고로슬래그 미분말을 콘크리트용 혼화재료로 사용 가능한지를 알아보기 위한 연구의 일환으로 고로슬래그 미분말 자체의 화학성분, 물리적 성질 등과 같은 품질에 대하여 분석 검토하였다. 아울러 고로슬래그 미분말을 몇 단계로 혼합한 모르터 및 콘크리트의 콘시스텐시와 각 재령별 압축강도 및 내약품성에 대하여 기초적인 실험을 실시해 본 결과 장기재령에서 압축강도가 증가되었으며, 약품에 대한 모르터의 저항성도 우수함을 알 수 있었다.

• 한국해양공학회지
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• 제23권5호
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• pp.54-60
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• 2009

Exposed to various environments, concrete confronts degradation by a lot of physical and chemical reaction. Though so many experiments and theorizations on the single condition of concrete degradation have been carried out by constant studies, the truth for now is that there are few studies on the compound phenomenon of degradation related with marine environments. Accordingly, this study measured the degree of degradation in the change of external shape, the change of unit weight and compressive strength, ultrasonic velocity test, and the change of length, etc. after exposing the specimen of cement mortar to the environment between 0 cycle and the maximum of 300 cycles under the condition of aquatic curing, freezing and thawing, and compound degradation, using mineral admixture effective for concrete degradation as a binder. The result indicated that the case of adding mineral admixture showed greater resistance than that of using OPC only, and specifically, the specimen with the additive of slag powder and three component system showed very excellent resistance to freezing and thawing, and compound degradation.