• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.25-26
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• 2022

The purpose of this study is to prevent serious disasters in cold weather by presenting an optimal blending design for securing high early strength when placing concrete by analyzing the properties and compressive strength of concrete formulations using high early strength admixture materials.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.73-77
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• 2006

This paper shows a study of the efficiency of expansive additive and shrinkage reducing admixture in controlling restrained shrinkage cracking of high performance concrete at early age. Free autogenous shrinkage test of $100{\times}100{\times}400mm$ concrete specimens and simulated completely-restrained test with VRTM(variable restraint testing machine) were performed. Creep and autogenous shrinkage of high-performance concrete with and without expansive additive and shrinkage reducing admixture were investigated by experiments that provided data on free autogenous shrinkage and restrained shrinkage. The results showed that the addition of expansive additive and shrinkage reducing admixture effectively reduced autogenous shrinkage and tensile stress in the restrained conditions. Also, it was found that the shrinkage stress was relaxed by 90% in high-performance concrete with and without expansive additive and shrinkage reducing admixtures at early age.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.133-138
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• 2007

This research goes into the field application cases about Flat slab concrete divide placing construction for the Multi-purpose Apartment. It is important to investigate sufficiently when mass concrete is applied to the substituted divide placing and admixture(blast furnace slag and fly ash). In addition, it is improved on the concrete quality by the job mix design which can decrease cracks caused by the heat of hydration, by the good compactability and the substitution of admixture that can prevent segregation when concrete is poured, and by the good conditioned fluidity which makes the efficiency of building construction. After considering the stated above, the sufficient prior consideration is important for a quality Improvement plan at the field use concrete of the Mass Concrete when divide placing and admixture are substituted and applied.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.180-185
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• 1994

An experimental study was carried out for the estimate of the properties of concrete contained an antiwashout admixtures. Properties of antiwashout under water concrete clearly differed from other types of concrete. This paper reports the effects of specific types, dosage of antiwashout admixtures and superplasticizer. The test results have indicated that dosage of antiwashout admixture and superplsticizer to improve the antiwashing property, fluidity and compressive strength will be approximately 2.5kg/$\textrm{m}^3$, 8~10kg/$\textrm{m}^3$ of the weight of concrete each. When cellulous ether type antiwashout admixture is added with a napthalen sulphonate superplasticizer, resulting in reduced whole properties of antiwasout under water concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.89-93
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• 1998

In order to enlarge effection use as well as to use as a cheafut raw material for high-strength concrete admixture, we manufactured high strength admixture by using various industrial by-products and then applied to 2nd concrete pro when concrete was added MSS, strength of concrete was promoted and had a excellent property than domestic D admixture. This result could be explained that adding of MSS accelerated the famat of ettringite($C_3A$, $3CaSO_4$, $32H_2O$) like needle crystal in steam curing a also promoted to cement solidification and shorten high pre-strength display. As a result of, strength of concrete added MSS pretented, above 850kgf/$\textrm{cm}^2$ in 7 days of long-period curing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.229-230
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• 2011

We could see that, the thinner the retaining wall is, the more advantageous Premixed Agent Type Waterproof method is in the aspect of economic efficiency. The reason is because, in the case of Premixed Agent Type Waterproof method, the thicker the retaining wall is, the higher the construction cost increases due to increase in the material quantity required which increases in proportion to the area in the case of Premixed Agent Type Waterproof method. We could see that, the thinner the retaining wall is, the more inferior the economic efficiency of Infiltration Type Waterproof method is to that of Premixed Agent Type Waterproof method, as, in the case of Infiltration Type Waterproof method, the quantity of material required is fixed in proportion to the area. Consequently, we concluded that Premixed Agent Type Waterproof method is economically advantageous up to the wall thickness of 700 mm and Infiltration Type Waterproof from 800 mm.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.741-744
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• 2003

In this study, the influence of chemical admixture on early strength development of concrete is discussed. According to the results, fluidity with variation of kinds of chemical admixture is lower in the case of acceleration type than in the case of normal type. Setting time of naphthalene acceleration type is shortened by I hour, and that of melamine is nearly same, but that of polycarbonic acid is somewhat retarded in comparison with that of naphthalene normal type. Early compressive strength gains 5MPa in about 18hours regardless of the kinds of chemical admixture. But as time elapses, compressive strength is higher in order of polycarbonic acid, naphthalene and melamine type. The relativity between compressive strength and the rebound value of P-type schmidt hammer is also favorable at early age, and compressive strength of 5MPa is estimated at the rebound value of 22.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.151-152
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• 2016

In this study, the shrinkage properties of concrete with the high-performance shrinkage admixture and the crack reinforcing materials applied to the high-flatness flooring of hypermarkets, outlets and warehouses was evaluated. The concrete with the popular shrinkage admixture is significantly reduced compared to the plain concrete without shrinkage admixture for the dry shrinkage deformation, and the difference of shrinkage ratio between the concretes has been shown to increase with increasing age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.105-106
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• 2013

The construction of modern society, the use of high-strength concrete structures is becoming frequent. Admixture has been reported as a factor causing the explosion occurred. This study was experimental research on high strength concrete according to the kinds of admixture. Admixture of four different mix. fire resistance test results are outstanding when using blast furnace slag aggregate. When using silica fume spalling phenomena were most violent.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.115-125
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• 1999

The purpose of this experimental research is to investigate the properties of workability and strength of the concrete containing admixtures such as silica fume, fly ash, ground granulated blast-furnace slag, and rice husk ash. For this purpose, the workability and the strength of the concrete containing each admixture were tested and analyzed according to the unit weight of binder and the replacement ratio of each admixture. As a result, considering their workability and strength, the existence of minimum binder weight and optimum replacement ratio of concrete containing admixture to plain concrete were obtained for each admixture.