• Title/Summary/Keyword: superplasticizer

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Study on Consistency Curve of Cement Mortar according to Superplasticizer type (고성능 AE 감수제 종류에 따른 시멘트 모르타르의 컨시스턴시 곡선 검토)

  • Lee, Gun-Young;Lee, Gun-Cheol;Choi, Jung-Gu;Park, Dong-Cheon
    • 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.

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Application of Powdered Superplasticizer to Improve of Slump Loss Rate in Recycled Aggregate Concrete (재생 골재 콘크리트의 슬럼프 손실 개선을 위한 분말형 감수제의 활용)

  • Yang, Keun-Hyeok;Sim, Jae-Il;Lee, Jae-Sam;Chung, Heon-Soo
    • Journal of the Korea Concrete Institute
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    • v.18 no.5 s.95
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    • pp.649-656
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    • 2006
  • In this study, powered superplasticizer(PSP) agents to improve the slump loss rate of recycled aggregate concrete were developed. To evaluate the variation of fluidity against elapsed time and the mechanical properties, twenty four specimens whose main variables had the mixing condition of aggregates, such as natural and recycled gravels, and natural and recycled fine aggregates, were tested. The concrete slump with a liquid superplasticizer greatly decreased against the elapsed time and dropped by less than 50% of initial slump after two hours. However the concrete slump with the PSP agents hardly varied until after half an hour and maintained more than 85% of initial slump even after an hour. Also the PSP agents made the compressive, splitting tensile, and flexural strength of concrete increased and the shrinkage strain decreased. Considering the properties improvement of concrete, it can be recommended that optimum mixing amount of the PSP agents should be 5% of the amount of cement.

Effect of Various Superplasticizers on the Hydration of Cement Paste (시멘트페이스트 수화 반응에 미치는 고유동화제의 영향성에 관한 연구)

  • Shin Jin-Yong;Kim Jae-Young;Hong Ji-Sook;Suh Jeong-Kwon;Lee Young-Seok
    • Journal of the Korea Concrete Institute
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    • v.17 no.6 s.90
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    • pp.1019-1024
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    • 2005
  • To research effects of various chemical superplasticizers(Lignosulfonic acid, Naphthalene sulfonated formaldehyde condensate, melamine sulfonated formaldehyde condensate, and Polycarboxylate) on the hydration of cement, experiments involving XRD, SEM, and DSC have been analysed with cement paste specimens. Regardless of types and dosages of superplasticizers, hydration reaction of specimen applied superplasticizer was delayed to 3 day, but then it showed similarity to plain which don't add superplasticizer. Moreover, the hydrating rate of cement paste was retarded as dosage of superplasticizer was increased. Also, kinetics related with hydrate of cement paste was slow in order of lignosulfonic acid, polycarboxylate, melamine and naphthalene sulfonated formaldehyde condensate. Nevertheless, when all kinds of chemical admixtures were used, morphologies of these hydrates were denser and more uniform than those of plain.

Fluidity and Strength Properties of Non-Sintered Cement Mortar according to the Addition of Superplasticizer (감수제 첨가에 따른 비소성 시멘트 모르타르의 유동성 및 강도 특성)

  • Jang, Kyung-Su;Na, Hyeong-Won;Byun, Hui-Jae;Hyung, Won-Gil
    • Journal of the Korea Institute of Building Construction
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    • v.22 no.5
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    • pp.441-450
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    • 2022
  • In this study, the fluidity and strength characteristics of NSC mortar according to the type and rate of addition of superplasticizer were analyzed to secure the fluidity of NSC composed of only slag and ash. Through the flow test, it was found that the fluidity of NSC was related to the basicity according to the binder condition, and the lower the reactivity, the higher the fluidity. When polycarboxylate is added, NSC mortar is considered to be more advantageous than plain mortar in terms of securing fluidity. As a result of the strength tests of NSC mortar containing Lignin or Polycarboxylate superplasticizer, it was found that the strength tends to increase as the basicity increases. In addition, when polycarboxylate is added, it is judged that the NSC mortar can secure adequate fluidity and strength at the same time. Through this experiment, an appropriate binder condition that satisfies the flowability while securing the strength was derived.

Field Application of the Concrete with the Combination of Drying Shrinkage-Reducing Superplasticizer and Double Layer Bubble Sheet (건조수축 저감형 유동화제 및 2 중 버블시트를 사용한 콘크리트의 현장적용)

  • Han, Cheon-Goo;Oh, Chi-Hyun;Shin, Jae-Kyung
    • Journal of the Korea Institute of Building Construction
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    • v.7 no.1 s.23
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    • pp.107-113
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    • 2007
  • This study investigates the filed application in Daebul Free Trade Zone applying both a flowing method using drying shrinkage-reducing superplasticizer(SRS) and an insulating curing method using double layer bubble sheet. Test results showed that fresh concrete satisfied target slump and air content. A structure adding SRS significantly decreased the total bleeding capacity and accelerated the setting time. As for the crack occurrence, the structure applying the flowing method and double bubble sheets simultaneously exhibited the most favorable crack endurance, while conventional concrete showed more than 1mm size of crack in overall. In addition, a structure applying the flowing concrete method partially presented the micro crack. For the area proportion of crack occurrence, the structure using the double bubble sheets indicated 9.8%, while others applying flowing concrete method was 28%, compared with that of conventional one. For the compressive strength of specimens, standard curing specimens indicated $3{\sim}33%$ higher value than that of specimens cured besides the field construction. The specimens containing SRS improved the strength of $2{\sim}6MPa$, which is $10{\sim}22%$ higher than that of conventional concrete.

Effects of compatibility between PNS Superplasticzer and soluble alkali of cements on performances of concrete (PNS계 고성능 감수제와 시멘트 수용성 알칼리양과의 상용성이 콘크리트 물성에 미치는 영향)

  • Ahn, Tae-ho;Park, Junhui;Sho, Kwangho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.4
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    • pp.173-177
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    • 2017
  • A polynaphthalenesulfonate (PNS) superplasticizer and its relation to the fluidity of cement paste (w/c = 0.35) has been investigated for three cements at a given dosage of PNS superplasticizer. Chemical properties of three cements were characterized with a XRD, XRF. The additive effects of $Na_2SO_4$ on the fresh concrete with w/c = 0.33 were also estimated by the measurement of compressive strength, slump, air content. The experimental results exhibited that the addition of sodium sulfate 2.6 % to the cement A and C improves slump loss. In case of cement E, the addition of sodium sulfate 1.3 % was effective.

Performance of High Strength Self-Compacting Concrete Beams under Different Modes of Failure

  • Harkouss, Raya Hassan;Hamad, Bilal Salim
    • International Journal of Concrete Structures and Materials
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    • v.9 no.1
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    • pp.69-88
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    • 2015
  • Self-consolidating concrete (SCC) is a stable and cohesive high consistency concrete mix with enhanced filling ability properties that reduce the need for mechanical compaction. Limited standards and specifications have been reported in the literature on the structural behavior of reinforced self-compacting concrete elements. The significance of the research presented in this paper stems from the need to investigate the effect of enhanced fluidity of SCC on the structural behavior of high strength self-consolidating reinforced concrete beams. To meet the objectives of this research, twelve reinforced concrete beams were prepared with two different generations of superplasticizers and designed to exhibit flexure, shear, or bond splitting failure. The compared beams were identical except for the type of superplasticizer being used (second generation sulphonated-based superplasticizer or third generation polycarboxylate-based superplasticizer). The outcomes of the experimental work revealed comparable resistance of beam specimens made with self-compacting (SCC) and conventional vibrated concrete (VC). The dissimilarities in the experimental values between the SCC and the control VC beams were not major, leading to the conclusion that the high flowability of SCC has little effect on the flexural, shear and bond strengths of concrete members.

Influence of Superplastisize Types on Hydration of Cement with Silica Fume (고성능 감수제 종류에 따른 실리카흄이 혼입된 시멘트 수화 특성)

  • Kang, Hyun-Ju;Song, Myong-Shin;Park, Jong-Hun;Song, Su-Jae
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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    • pp.504-509
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    • 2011
  • In this study, the effect of superplasticizers on the dispersibility and hydration properties of cement with silica fume were investigated. Superplasticizers are used Naphthalene type, Ligno-sulfate type and polycarboxylate type. Compared with plastic viscosity of cement paste without superplasticizers(Plain), plastic viscosity of cement paste with superplasticizers are reduced and yield stress of cement pastes with each superplasticizer is increased rather than Plain. And then, plastic viscosity of cement paste with Naphthalene type superplasticizer was the least of all types. Compared with other two types, setting and hydration of cement paste with Polycarboxylate type(PC) superplasticizer is very fast. At compressive strength after 3-day, PC is higher than other two types, But, compressive strength of after 7-day and 28-day, PC is smaller than other two types.

Rheological Properties of Cement Pastes Containing Mineral Admixtures and Superplasticizer (광물질 혼합재와 고유동화제를 첨가한 시멘트 페이스트의 유동특성)

  • Song, Jong-Taek;Shin, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.11 s.282
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    • pp.737-742
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    • 2005
  • Rheological properties of ordinary portland cement (OPC) containing metakaoline (MK), granulated blast furnace slag (GBS) and polycarboxylate type superplasticizer (PCA) were investigated using a mini-slump test, sedimentation test and viscometer. Fluidity of cement pastes containing MK (OPC-MK, OPC-MK-GBS systems) with PCA were higher than those of the cement pastes without MK(OPC, OPC-GBS systems). Colloid suspensions with $0.1\%$ PCA were changed from stable sedimentation behaviors to flocculation behaviors in the OPC-MK, OPC-GBS and OPC-MK-GBS systems. The colloid suspensions showed stable sedimentation behaviors with PCA greater than $0.2\%$. The OPC system showed shear thinning behavior. However, the other systems showed weak shear thinning behaviors with PCA. Rheological properties of cement pastes were improved when MK and GBS were contained together. The rheological properties of OPC-MK, OPC-GBS and OPC-MK-GBS systems were improved by PCA added greater than $0.2\%$.

Corrosion Inhibition Properties of Steel bars in Reinforced Concrete Using Superplasticizer with Air Entrained Agent (고성능AE감수제를 사용한 콘크리트의 철근부식 저항성)

  • Lee, Mun-Hwan;Jung, Mi-Kyung;Oh, Se-Chul;Bae, Kyu-Woong;Seo, Chee-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.4
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    • pp.149-160
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    • 2000
  • As systematic methodologies are required for the evaluation on the durability of reinforced concrete structure, it is necessary to study and examine every factor which deteriorates the durability of structures. This paper aims to define factors affecting rebar corrosion and to establish a basis for a prediction of serviceability, regarding a state of harmful corrosion as a state when crack begins on the surface of concrete. The study results are followings; The corrosive current has changed by types of mixture, and this property enables the evaluations of corrosion resistance by mixture and concrete cover. The specimen using AE superplasticizer has better corrosion-resistance properties than non-AE specimen, as well those having low W/C and high unit cement weight. The procedure for calculation of durable year in this study is able to use as an indicator to establish mixture factors such as unit cement weight, W/C, amount of admixture, etc.

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