• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.349-354
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• 2003

The objective of this paper is to investigate the length change of high performance concrete using expansive additives to reduce autogenous shrinkage and drying shrinkage. The kinds and the contents of expansive additives are varied. The expansive additives are used made from Japan(CSA type;JEA), China(CSA type;CEA) and Korea(gypsum type; KEA), respectively. According to results, remarkable variations of the properties at fresh concrete are not found with dosage of expansive additives. For compressive strength, it decreases about 6-10% with expansive additives of 10%. Autogenous shrinkage decreases about 32%, and drying shrinkage does about 35%, respectively, with expansive additives of 5%, and about 68% and about 55%, with expansive additives of 10%. Accordingly, expansive additives demand requires 10% by cement weight in order to reduce shrinkage of high performance concrete more effectively in the sphere of this study, and JEA shows the best shrinkage reducing performance among the tested expansive additives.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.386-391
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• 1998

Recently, high performance concrete developed has a good quality at fresh and hardened state, but high binder contents results in spending much money on manufacturing and many cracks by drying and autogenous shrinkage. Therefore, in this paper, not only prevention of cracks caused by drying and autogenous shrinkage, but improvement of quality and accmplishment of economy by applying F.A(fly ash), S.F(silica fume) and CSA(calcium sulfa aluminate) expansive additives as an inorganic admixtures in W/B 35% are discussed. According to the experimental results, when 5% of CSA Expansive additives and 15:5 (F.A:S.F)are replaced at unit cement content, high performance concrete with both good compensation of drying and autogenous shrinkage at hardened state is accomplished.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.19-22
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• 1998

This study is investigate the properties of high performance concrete at W/B of 35%, used with silica fume and CSA expansive additives, which is used to improve the concrete qualities and prevent the drying-shrinkage. According to the results, the fluidity of concrete shows a decline with the increase of replacement percentage of silica fume and proportions of expansive additives. A higher strength is obtained at 5% of replacement percentage of silica fume, while the compensation achieves in drying-shrinkage of concrete at 5% of expansive additives.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.23-28
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• 1998

In this paper, the compensation of the shrinkage in high performance concrete by applying CSA expansive additives are discussed. According to toe experimental results, fluidity and strength decrease with the increase of the dosage of expansive additives. When 5% of expansive additive are mixed, not only high fluidity and strength, but also the compensation of drying-shrinkage can be achieved.

• 한국건축시공학회지
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• 제8권2호
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• pp.99-106
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• 2008

To improve concrete tensile strength and bending strength, New plan that have more economical and simple manufacture process is groped. By an alternative plan, chemical pre-stressed concrete is presented. In this study, we analyzed the rheological properties of cement paste with the kind and replacement ratio of k-type CSA type expansive additives that is used mainly in domestic. and we suggested that the algorithm of a mixing plan in the chemical pre-stressed concrete and from this, we presented the basic report for the right mixing plan. From the results, Flow increased more or less according to use of expansive additives. This phenomenon was observed by increasing paste amount that shows as substitution for expansive additives that specific gravity is smaller than that of cement. As linear regression a result supposing paste that mix expansive additives by Bingham plastic fluid. The shear rate and shear stress expressed high interrelationship. therefore, flow analysis of quantitative was available. The plastic viscosity following to replacement ratio of expansive additives is no change almost, the yield value is decreased in proportion to the added amount of expansive additives. Through this experiment, we could evaluate rheological properties of cement paste using the expansive additives. Hereafter by an additional experiment, we must confirm stability assessment of material separation by using the aggregate with the kind and replacement ratio of expansive additives.

• 콘크리트학회지
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• 제8권6호
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• pp.59-66
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• 1996

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.151-156
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• 1998

Concrete structures is appeared the shrinkage after being harden of the hydration effect of cement. To overcome this disadvantage, expansive additives are used. In our country, the most popular expansive additives are hauyne(CSA) or free lime(free-CaO) systems. These expansive additives are used to expansive cement mortar or concrete materials. In this study, we analyzed the expansive property mechanism about the hydration reaction of the free lime systems and in particular we convinced size distributions of the free lime size affect the expansion ratio with expansion ratio with experiments. We carried out the experiment for the expansive properties by using the soundness molds and with various the humidity and dry setting conditions. The hydration reactions of the free lime affect the reaction properties according to the relative humidity by laboratory experiments.

• 콘크리트학회지
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• 제11권1호
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• pp.141-148
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• 1999

최근 개발되고 있는 고유동, 고강도 및 고내구성을 발휘하는 고성능 콘크리트는 현대개념에 부응하는 양호한 품질을 발휘하는 이면에 물결합재비가 작고 단위결합재량이 많은 배합일수록 비경제적 및 건주수축과 자기수축이 대단히 커진다는 것이 보고되고 있고, 경우에 따라서는 자기수축만으로도 균열이 발생하는 일이 지적되고 있다. 따라서 본 연구에서는 무기질 혼화재인 플라이애쉬, 실리카 흄 및 플라이애쉬:실리카 흄 치환비 변화로써 워커빌리티등 각종품질의 향상과 구조물에 발생되는 건조수축 및 자기수출 균열을 CSA계 팽창재로 방지하므로써, 경제적이고 저균열${\cdot}$고품질인 고성능 콘크리트를 개발하고자 하였다. 연구결과 팽창재 혼입율 5%, F.A:S.F 15:5로 치환하면 유동성 및 강도특성이 양호하면서 건조수축 및 자기수축 보상효과가 있는 양호한 고성능 콘크리트가 성취될 수 있음을 알 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.87-90
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• 2007

The purpose of this study is to investigate the properties of concrete with the kinds and addition of expansive additives. 2 kinds of expansive additives produced in our country and 0, 10, 20, 30, 40% of ratio of addition rate are selected for this experiment. According to experimental results, flow, slump and air rate of concrete with expansive additives is nearly same with its of plain concrete and compressive strength, tensile strength of concrete with expansive additives at 28 days is higher than that of plain concrete. Therefore, The expansion concrete is able to manufactured so it consumes by restricted effects.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.585-588
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• 1999

This study is performed to verify the effect of CSA expansive additives for concrete by material properties test and 4 point-bendig test of RC slabs. The result shows that the variations of compress strength, bending strength, and modulus of elasticity of expansive concrete are the same as those of plain concrete. And the crack load of RC slabs with expansive concrete are increased in comparision with that of plain concrete, but the ultimate strength of RC slabs with expansive concrete is decreased.