• Title/Summary/Keyword: 수중불분리성

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Characteristics of Antiwashout Underwater Concrete with the Mineral Admixtures for Underwater Concrete Structures (수중 콘크리트 구조물을 위한 광물질 혼화제를 첨가한 수중불분리성 콘크리트의 특성)

  • 원종필;임경하;박찬기;김완영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.6
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    • pp.90-98
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    • 2002
  • Recently the use of the antiwashout underwater concrete with the antiwashout admixture is increased considerably. Antiwashout underwater concrete is quite different in concept from conventional underwater concrete. By mixing an antiwashout admixture with concrete, the viscosity of the concrete is increased and its resistance to segregation under the washing action of water is enhanced. The aim of this research is to evaluate the fundamental characteristics and permeability of antiwashout underwater concrete with fly ash and blast-furnace slag. Test Results of antiwashout underwater concrete with fly ash and blast-furnace slag fluence can provide its excellent fundamental characteristics and resistance of permeability.

Properties of Antiwashout Underwater Concrete Using the GGBF Slag (고로슬래그미분말을 활용한 수중불분리성콘크리트)

  • 문한영;김성수;이병덕;이재준
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10c
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    • pp.83-86
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    • 1998
  • Recently, underwater concrete constructions are increasing. Therefore it is considered important to control the quality of underwater concrete. In this paper, we have an intention of evaluating fundamental properties of underwater concrete using the Ground Granulated Blast Furnace Slag (GGBF Slag). Thus, it has been investigated that the slump flow of the concrete, pH value and suspended solids in solution, compressive strength on both of specimens made above and below water. Also the percentage of GGBF Slag was found to alter the filling-up in underwater concrete.

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Assessment on the Seawater Attack Resistance of Antiwashout Underwater Concrete (수중불분리성 콘크리트의 해수침식에 대한저항성 평가)

  • 문한영;김성수;안태송;이승태;김종필
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.683-688
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    • 2001
  • In case of constructing the concrete structures under seawater environment, the concrete suffers from deterioration due to penetration of various ions such as chloride, sulfate and magnesium in seawater. Tn the present study, Immersion tests with artificial seawater were carried out to investigate the resistance to seawater attack of antiwashout underwater concrete. From the results of compressive strength, it was found that blended cement concrete due to mineral admixtures such as fly ash(FA) and ground granulated blast-furnace slag(SGC), were superior to ordinary portland cement concrete with respect to the resistance to seawater attack. Moreover, XRD analysis indicated that the formed reactants of ordinary portland cement paste by sulfate and magnesium ions led to the deterioration of concrete. As expected, however, the blended cements with FA or SGC have a good resistance to seawater attack. This paper would discuss the mechanism of seawater deterioration and benefical effects of antiwashout underwater concretes with mineral admixtures.

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Properties of Antiwashout Underwater Concrete Containing Fly Ash (플라이애시를 혼합한 수중불분리성 콘크리트의 제물성)

  • 문한영;김성수;이재준;전중규
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.609-612
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    • 1999
  • Recently, the antiwashout underwater concrete with an antiwashout admixtures has been increasingly used for underwater structures. However, the credibility of antiwashout underwater concrete was brought up as problems because it seldom was applied to fields. In this study, experiments were made on the basic properties of antiwashout underwater concrete replaced with fly ash up to 30% to improve its properties. Resultant to the test, we got the results as follow; funnel flow time was decreased, the slump flow was increased and the elevation of head was decreased rapidly whereas the amount of suspended solids became high, pH became low. In view of 70%, the standard ratio of compressive strengths between cast in water and in air, it was obtained the result that the ratio was over 90% at 28days.

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High-strength Antiwashout Underwater Concrete Containing the GGBF Slag (고로슬래그 미분말을 혼합한 고강도 수중불분리성 콘크리트)

  • 문한영;송용규;전중규;김태욱
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.199-202
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    • 1999
  • Recently, the antiwahout underwater concrete with an natiwashout admixture has been increasingly used for underwater structures. However, the credibility of antiwahout underwater concrete was brought up as problems because it was seldom applied to fields. In this study, experiments were made on the basic properties of antiwashout underwater concrete replaced with GGBF Slag from 40% to 60% to improve its properties. Resultant to the test, we got the results as follows; the difference of U-type heght was decreased, and the slump flow was increased. Whereas the amount of suspended solids became high as to increasing the replacement ratio of GGBF Slag, pH value became low. Beacause the ratio of compressive strengths (in water compared to in air) at 28days was obtained over 90%, its value is satisfied with 70% of a criterion.

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Study on the Properties of Antiwashout Underwater Concrete as to Fine aggreate Kinds (잔골재의 종류에 따른 수중불분리성 콘크리트의 특성에 관한 연구)

  • 박세인;신현필;이환우;김종수;김명식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.941-946
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    • 2001
  • In this study, three kinds of fine aggregate (river sand, sea sand, crushed sand) were used and four different s/a (38%, 40%, 42%, 45%) were applied separately to this experimental for get the conclusion written below. Regardless of kinds of fine aggregate and casting-curing condition, maximum unit weight is seen at 40% of s/a and also to be seen in case of crushed sand. It's for that specific gravity of crushed sand is bigger comparatively than river sand and sea snad's one. Compressive strength is measured river sand, crushed sand, sea sand by order of size ; Regardless of variation of s/3, casting-curing condition and age. Compressive strength recorded maximum when s/a is 42% whatever sort of fine aggregate are. As the result, according to references, the optimum s/a of underwater antiwashout concrete is 40% but in this study, from compressive strength of view, the optimum s/a of underwater antiwashout concrete is 42%.

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Study on the Properties of Antiwashout Underwater Concrete with Variation of Blend Ratio of Crushed Sand (부순모래 혼입률 변화에 따른 수중불분리성 콘크리트의 특성 연구)

  • 박세인;오광영;이환우;김종수;김명식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.427-432
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    • 2001
  • In this study, crushed sand is blended with river sand and sea sand, to investigate the quality change of antiwashout underwater concrete with variation of blend ratio of crushed sand(0%, 20%, 40%, 60%, 80%, 100%). To see experiment conclusion, the more blend ratio of crushed sand increases, the more unit weight increases. Because the for that specific gravity of crushed sand is higher comparatively than that of river sand and sea sand. Higher compressive strength is measured following the order of river sand, crushed sand, sea sand regardless of age and casting-curing condition. Except for case of using river sand, blend ratio of 40% is appeared on most compressive strength. So the optimum blend ratio of crushed sand is 40% from the view point of compressive strength.

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Fundamental Properties of Antiwashout Underwater Concrete (수중불분리성 콘크리트의 기초물성에 대하여)

  • Kim, Jin-Cheol;Jeong, Yong;Park, Sung-Hak;Park, Ki-Cheong
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.1-7
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    • 1995
  • The objective of this experimental investigation was to examine the fundamental properties of antiwashout underwater concrete. Expriments were conducted on the antiwashout property in underwater, the compressive strength in the air and in underwater, setting time, slump flow loss. As a result, a dosage of 2.0-2.5kg/$\textrm{m}^3$ antiwashout admixture was found to be appropriate not to cause water pollution and to provide a reliably good compressive strength in underwater concrete. Also, the experimental results showed that the amount of less than 50mg/$\ell$ suspended solid was required to obtain the underwater to air compressive strength ratio of more than 80%

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An Experimental Studies on Properties of Antiwashout Admixtures (수중불분리성 혼화제의 성능평가를 위한 실험적 연구)

  • 문한영;김성수;이재준
    • Journal of the Korea Concrete Institute
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    • v.11 no.5
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    • pp.51-60
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    • 1999
  • When placed under water, concrete is diluted with separating cementitious material and as a result the quality of concrete becomes poor. So as to solve the problem, underwater concrete is increasingly used for the construction and repair of the concrete structure under water. In this paper, 4 kinds of antiwashout admixtures and varying sand percentages were chosen to measure the suspended solids, pH, air contents, setting time and compressive strength of underwater concrete, and they meet "Standard for antiwashout admixture used for concrete". When sand percentage is 43%, the fluidity and filling of underwater concrete are superior to the others.he others.

Experiments on Mechanical Characteristics of Anti-Washout Concrete with Mixing and Placing Condition (배합 및 타설조건에 따른 수중불분리성 콘크리트의 역학적특성 변화에 관한 실험)

  • Yang, Eun-Ik;Choi, Hong-Shik;Heo, Gweon;Lee, Si-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.141-146
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    • 1999
  • An experimental study is carried out to estimate the effects of mixing and placing condition on the mechanical properties of anti-washout concrete. According to the test results, mixing method and placing temperature do affect the characteristics of rrsh concrete, while they do not affect the strength development of anti-washout concrete. But, concrete strength was greatly affected by the placing condition and placing height. Concrete strength decreases linearly as the placing height increased. Compared to the normal concrete, the increase in strength is not associated much with an increase in the elastic modulus of anti-washout concrete.

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