• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.35-36
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• 2016

Recently, with the increasing demand of high performance of concrete, the mix design of concrete mixture has became low water-to-binder ratio with high binder content. To compensate these trend of mix design, high range water reducer, or superplascizier has been invented to achieve high flowable concrete. Although this superplasticizer provides favorable workability based on its dispersing action on the components of concrete mixture, it has an limitation of decreasing viscosity of the mixture, and thus it is difficult to secure sufficient workability for high performance concrete mixtures with high binder content. To improve the workability of concrete with high viscosity, recently, low-viscosity type superplasticizer was introduced, and in this research, a fundamental properties of low-viscosity type superplasticizer is evaluated.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.277-280
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• 2004

Recently, as structure is more higher and bigger, we need high strength and high performance concrete. Therefore it is necessary superplasticizer for high strength and high performance concrete. In this study, it is examined the properties of flow, air content and strength of concrete with polycarboxylate superplasticizer in comparison with existing superplasticizer. First, The slump loss of concrete used polycarboxylate superplasticizer showed 2cm until 120 minutes. Second, The air content loss of concrete used polycarboxylate superplasticizer showed $1\%$ until 120 minutes. Third, It is possible to manufacture $1000kgf/cm^2$ strength concrete using polycarboxylate superplasticizer with $806kg/m^3$ cement content, $18\%$ water-binder ratio, $15\%$ silica fume, $10\%$ fly-ash content.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.115-122
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• 2003

In order to analyze liquidity change according to increasing the charge of superplasticizer, we inputted charges by dividing into six steps, 0% through 1.25%; at the same time, to observe liquidity change according to the change of charge-time, we carried out the experiment applying 30-minute intervals, i.e. at beginning of mixing, 30, 60 and 90 minutes. The results are below. 1) According to increasing the charge of superplasticizer, the liquidity of concrete was enhanced, however, when inputted 1.25%, a little segregation was occurred, which allowed us to make a conclusion that concrete performance would be deteriorated due to this segregation. 2) When we inputted 1.25% of superplsticizer, steady liquidity features were shown regardless of the charge-time of concrete, which allowed us to make a conclusion that this input would be the best for liquidity performance considering only liquidity features. 3) After analyzing the dynamical features of liquid concrete, the result showed that there was not significant effect on revelation of compressive strength. We concluded form this result that there was no influence on the stripping-time of a mold form. 4) When we charge superplasticizer in concrete more than 1%, we, in advance, should clearly judge the concrete performance required during constructing in site, as it were, the compressive strength or liquidity etc.; furthermore, we had better decide a charge and input-time of superplasticizer to meet the required performance.

• Resources Recycling
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• v.25 no.3
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• pp.20-28
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• 2016

Assessment on adequate dosage of superplasticizer in eco-friendly ultra-high performance concrete (UHPC) containing industrial by-products was carried out from the standpoint of workability. Various types of industrial by-products, including blast-furnace slag, coal bottom ash and rapid-cooled electric arc furnace oxidizing slag, were utilized, and the effects of dosage of superplasticizer on the workability and strength of UHPC containing the by-products were evaluated. By utilizing the by-products, the workability of UHPC was improved and required dosage of superplasticizer was reduced. In addition, the material cost for UHPC with by-products was decreased due to reduced dosage of superplasticizer.

• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.387-393
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• 2010

To improve concrete quality one of the most widely used chemical admixtures is polycarboxylate type superplasticizer. Unlike lignosulfonate and naphthalene-sulfonate, it has high dispersion property and excellent sustainable dispersion property for cement and concrete. Thus, polycarboxylate type superplasticizer has been widely used as a high-performance water reducing admixture together with silica fume in high-performance concrete and other applications for the dispersion of high-strength concrete over 100 MPa. However, even though there have been many studied on the dispersion of concrete by the structure of polycarboxylate type superplasticizer, there have a few studied that clarified the relationships between its rheological properties and microstructure properties in the early hydration behavior of ordinary portland cement. To investigate the correlations between the rheological properties and microstructure of cementitious materials with polycarboxylate type superplasticizer, this study experimented on the rheology, pore structure, heat evolution, and consistency in early hydration as well as on the compressive strength by early dispersion characteristics.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.265-268
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• 2003

This study discusses the fundamental properties of high performance concrete and autogenous drying shrinkage with the kinds and the adding amount of superplasticizer. According to results, drying shrinkage hardly shows differences by the kinds of superplasticizer, and is reduced with an increase of the adding ratio. Autogenous shrinkage is reduced in order of HP>HN>HM, but does not make a big difference. As the adding amount of superplasticizer increases, autogenous shrinkage is reduced due to a decrease of cement content which influences on autogenous shrinkage seriously.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.65-66
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• 2022

In this study, the setting characteristics of the high range water reducing agent to minimize the retardation of UHPC were confirmed to minimize the setting time in the hardening of UHPC. As a result of the study, there was a slight change depending on the difference in the type of Superplasticizer, K > P > D = S > E in the order of condensation promotion, and E > S = D = K > P on the 28th day.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.179-180
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• 2015

Recently, admixture manufacturers have improved the performance of admixtures to solve problems caused by high viscosity of high performance admixtures, and accordingly, it is expected to affect fluidity of concrete using admixtures. Therefore, in this research, how each kind of HAE affects consistency curve of cement mortar was examined.

• Computers and Concrete
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• v.19 no.6
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• pp.667-675
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• 2017

One of the main disadvantages of Ultra High Performance Concrete exists in the large suggested value of UHPC ingredients. The purpose of this study was to find the models mechanical properties which included a 7, 14 and 28-day compressive strength test, a 28-day splitting tensile and modulus of rupture test for Ultra High Performance Concrete, as well as, a study on the interaction and correlation of five variables that includes silica fume amount (SF), cement 42.5 amount, steel fiber amount, superplasticizer amount (SP), and w/c mechanical properties of UHPC. The response surface methodology was analyzed between the variables and responses. The relationships and mathematical models in terms of coded variables were established by ANOVA. The validity of models were checked by experimental values. The offered models are valid for mixes with the fraction proportion of fine aggregate as; 0.70-1.30 cement amount, 0.15-0.30 silica fume, 0.04-0.08 superplasticizer, 0.10-0.20 steel fiber, and 0.18-0.32 water binder ratio.

• Computers and Concrete
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• v.17 no.4
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• pp.477-488
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• 2016

This paper aims to model the effects of five different variables which includes: cement content (C), the steel fiber amount (F), the silica fume amount (SF), the superplasticizer (SP), the silica fume amount (SF), and the water to cementitious ratio (w/c) on 28 days flexural toughness of Ultra High Performance Concrete (UHPC) as well as, a study on the variable interactions and correlations by using analyze of variance (ANOVA) and response surface methodology (RSM). The variables were compared by fine aggregate mass. The model will be valid for the mixes with 0.18 to 0.32 w/c ratio, 4 to 8 percent steel fiber, 7 to 13 percent cement, 15 to 30 percent silica fume, and 4 to 8 percent superplasticizer by fine aggregate mass.