• 제목/요약/키워드: Concrete Characteristics

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고로슬래그미분말 콘크리트의 초기재령특성과 중성화에 관한 연구 (A Study on Characteristics of Early Age Pore-structure and Carbonation of Ground Granulated Blast Furnace Slag Concrete)

  • 변근주;박성준;하주형;송하원
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.107-110
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    • 1999
  • The objective of this study is to obtain characteristics of early age pore-structure and carbonation of concrete using ground granulated blast furnace slag (GGBFS). The durability of GGBFS concrete should be evaluated for wide use of the GGBFS. As for that evaluation, an analysis on early age pore-structure characteristics of GGBFS concrete are very important, Carbonation depths of GGBFS concrete, which are known to be larger than that of OPC, are different according to replacement ratios and fineness of slag. Because sea sand as fine aggregate is much used recently, it is also necessary to analyze characteristics of carbonation of GGBFS concrete. In this study, The micro-pore structure formation characteristics of GGBFS concrete are obtained through the test of GGBFS mortars with different fineness and replacement ratio of GGBFS. The carbonation of GGBFS concrete is also investigated by acclerated carbonation test for early age GGBFS concrete.

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경량기포콘크리트의 개발과 역학적 특성에 관한 연구 (Development of Lightweight Foamed Concrete Using Polymer Foam Agent and its Mechanical Properties)

  • 변근주;박상순;송하원
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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    • pp.358-365
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    • 1996
  • Lightweight foamed concrete is a concrete which is lighter than normal concrete by mixing prefoamed foam in cement slurry. The objective of this study are to develop prefoamed optimal lightweight foamed concrete using polymer foam agent and to obtain its mechanical characteristics experimentally. This paper presents extensive test data on young's modulus, poisson's ratio, stress-strain curve, the characteristics of strength of the foamed concrete and also presents the mechanical characteristics of the foamed concrete according to foam sizes.

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조기강도 콘크리트의 내구특성 (Durability Characteristics of High-Early-Strength Concrete)

  • 원종필;김현호;안태송
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.991-996
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    • 2001
  • The long-term durability characteristics of high-early-strength concrete were assessed. The effect of long-term durability characteristics of high-early-strength concrete were investigated. In experiment, two different types of fiber were adopted for improvement of durability. High-early-strength fiber reinforced concretes using regulated-set cements are compared with high-early-strength concrete without fiber. The durability performance of the laboratory-cured high-early-strength concrete specimens was determined by conducting an accelerated chloride permeability, abrasion resistance, freeze-thaw, surface deicer salt scaling and wet-dry repetition test. The results indicated that incorporation of fibers enhance durability performance.

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폴리에스터 폴리머 콘크리트의 워커빌리티 특성 (Workability Characteristics of Polyester Polymer Concrete)

  • 연규석;김광우;이봉학
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1991년도 봄 학술발표회 논문집
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    • pp.87-92
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    • 1991
  • Since the material property of binder in polyester polymer concrete has a viscous mechanism, the workability of polyester polymer concrete mixture showed different characteristics from that of cement concretes. Therefore, this study was devised to evaluate workability characteristics of polyester polymer concrete using slump and flow tests. Study results showed that the test temperature and ST/UP ratio were the most dominantly affecting factor on the viscosity of binder, and viscosity of the binder was strongly correlated with the workability of polyester polymer concrete mixture.

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시멘트종류를 변화시킨 프리캐스트 고강도 콘크리트의 실험적 연구 - 압축강도특성을 중심으로 - (An Experimental Study of Precast Concrete Alters Cement Types of High-Strength Concrete)

  • 박흥이;기전도;김성진;이회근;박병근;정상진
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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    • pp.65-68
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    • 2009
  • Recently, as architectural concrete structures become high-rise and megastructured, concrete become high-strengthened and, by ensuring products of more stability, and rationalization of construction are required.large cross-sectional precast concrete members such as columns show large temperature increase in manufacturing process not only by external heating but also by concrete itself's hydration heating. Therefore, it is expected that specimen for management to predict strength and compression strength of precast concrete member shows different strength characteristics. Concerning this, in order to suggest strength characteristics of high strength mass concrete suitable for precast concrete application, this study comprises the inclusive investigations on the relations between core strength and the strength characteristics per member cross-section dimensional value and per water-bonding material ratio value.

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프리캐스트 콘크리트 적용을 위한 고강도 매스 콘크리트 부재의 강도 특성에 관한 실험적 연구 (An Experimetal Study on Strength Characteristics of Mass Concrete Cast with High-Strength Concrete for Precast Application.)

  • 박조현;김성진;백민수;이승훈;박병근;정상진
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2007년도 추계 학술논문 발표대회
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    • pp.49-52
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    • 2007
  • Recently, as architectural concrete structures become high-rise and megastructured, concrete become high-strengthened and, by ensuring products of more stability, air compression and rationalization of construction are required. In general, product management test of precast concrete member, specimen for management cured in the same condition with precast concrete member is substitutively used for strength test. However, large cross-sectional precast concrete members such as columns show large temperature increase in manufacturing process not only by external heating but also by concrete itself's hydration heating. Therefore, it is expected that specimen for management to predict strength and compression strength of precast concrete member shows different temperature history and strength characteristics. Concerning this, in order to suggest temperature history and strength characteristics of high strength mass concrete suitable for precast concrete application, this study comprises the inclusive investigations on the relations between management specimen with similar temperature history and core strength, and the strength characteristics per member cross-section dimensional value and per water-bonding material ratio value.

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폐주물사를 사용한 콘크리트의 강도특성에 관한 연구 (A study on the Strength Characteristics of Concrete Using Foundry Waste Sand)

  • 최연왕;최재진;김기형;김용직
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.237-240
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    • 1999
  • This study was performed to analyze strength characteristics of concrete using FWS(foundry waste sand), as a way of study for reusing the FWS disused in the foundry as the fine aggregate for concrete. As the experimental results, the slump of concrete showed a decline with the increase of replacement ratio of FWS. The compressive strength of concrete made with FWS 25% replacement river sand showed higher value than that of concrete not containing FWS, but the flexural strength of concrete containing FWS was decreased 21% compared with that of concrete not containing FWS at age of 28days.

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미세구조 특성을 고려한 초기재령 콘크리트의 강도예측모델 (Strength Estimation Model for Early-Age Concrete Considering Microstructural Characteristics)

  • 황수덕;김의태;이광명
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.397-402
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    • 2001
  • Microstructural characteristics such as hydrates and porosity greatly influence the development of concrete strength. In this study, a strength estimation model for early-age concrete considerig, the microstructural characteristics was proposed, which considers the effects of both an increment of degree of hydration and capillary porosity on a strength increment. Hydration modeling and compressive strength test with curing temperature and curing ages were carried out. By comparing test results with estimated strength, it is found that the strength estimation model can estimate compressive strength of early-age concrete with curing ages and curing temperature within a margin of error.

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Experimental Lnvestigation on Mechanical Characteristics and Environmental Effects on Rubber Concrete

  • Khorrami, Morteza;Vafai, Abolhassan;Khalilitabas, Ahmad A.;Desai, Chandrakant S.;Ardakani, M. H. Majedi
    • International Journal of Concrete Structures and Materials
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    • 제4권1호
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    • pp.17-23
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    • 2010
  • The feasibility of the use of scrap tire rubber in concrete was investigated. The tests conducted in two groups: replacing of coarse aggregates with crumb rubber and cement particles with rubber powder. To distinguish the properties of new concrete, the following mechanical and durability tests were designed: compressive, tensile and flexural strength, permeability and water absorption. Rubber addition could affect the concrete properties depend on the type and percentage of the rubber added. Although the rubber addition modifies the mechanical characteristics of concrete in a way, but higher rubber content could not be useful. Concrete durability showed more dependency to the type of rubber instead of percentage of rubber. Moreover, to optimize the mechanical and durability of rubberized concrete, the useful percentage of rubber has been recommended.

철근의 피로특성에 관한 실험적 연구 (Experimental Study on Fatigue Characteristics of Reinforcing Bars)

  • 변근주;송하원;노병철;양재성
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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    • pp.312-316
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    • 1996
  • Flexural fatigue strength of reinforced concrete members can be controlled by fatigue characteristics of concrete and reinforcing bars because the reinforced concrete members are composite members consisted of the concrete and the reinforcing bars. Since the fatigue characteristics of the reinforcing bars are different from static strength characteristics of those, it is necessary to obtain the fatigue characteristics of reinforcing bars directly from fatigue test. In this paper, the fatigue characteristics like fatigue strength of reinforcing bars with different diameters and different yield-strengths are obtained experimentally and the analysis and comparison of fatigue test results are presented. For the experiment, most widely used reinforcing bars manufactured by two domestic companies were randomly selected and direct tension fatigue tests were performed.

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