• 제목/요약/키워드: Concrete cylinder specimen

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Double-Punch Test에 의한 콘크리트의 인장강도 시험에 관한 연구 (A Study on Double - Punch Test for Tensile Strength of Concrete)

  • 이우종;고재군
    • 한국농공학회지
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    • 제30권2호
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    • pp.82-94
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    • 1988
  • The purpose of this study is to introduce the Double Punch test method which is an indirect testing method of tensile strength of concrete, and to compare with the tensile strength of concrete as determined by the split-cylinder test, a practical method for performing the Double Punch test to obtain the tensile strength of concrete is proposed and recommended for general use. In this study, the dimensions of cylindrical specimens used in the Double-Punch test were 15X30cm, 15X15cm, 10${\times}$(20cm, and 5${\times}$l0cm, and in the split-cylinder test were 15${\times}$(30cm, 15${\times}$(15cm, and 10${\times}$(20cm. And the diameters of loading punches used in the Double-Punch test were 1.5cm, 2.5cm, and 3.5 cm. The results obtained from tests are summarized as follows ; 1. In the split-cylinder test, the tensile strength of concrete by the linear elasticity theory is similar to that of plasticity theory. 2. Both split-cylinder test and Double-Punch test, tensile strength of concrete is increased with decreasing specimen size. This tendency is identical when the ratio of specimen diameter to height is 1: 2, but that tendency is quite different when the ratio is 1: 3. In the Double-Punch test, if specimen size is constant, by increasing the punch size, tensile strength of concrete is increased, too. 4. Using a 15 ${\times}$( 15 cm cylinder specimen and 3.5 cm diameter punch in the Double Punch test would give the most uniform and consistent result in tensile strength, and the result showed a gQod correlation with splitting tensile strength from 15 x 30cm specimen. 5. In order to obtain satisfactory results and to nuninuze variability, it is proposed that specimens of 15 cm in diameter and 15 cm in height with two 3.5 cm diameter punches should be used. It seems, therefore, reasonable tt) take f't=0.0024 P(kg / cm$^2$) as a working formula for computing the tensile strength in the Double Punch test for concrete.

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시험체 형상이 고인성시멘트복합체 인장거동에 미치는 영향 (Influence of Specimen Shapes on Tensile Behaviors of High Performance Fiber Reinforced Cement Composites)

  • 양일승;윤현도;한병찬;신홍철;박완신;김선우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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    • pp.65-68
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    • 2005
  • Social requirements to the civil and building structures have been changed in accordance with the social and economic progress. It is very important to develop the innovative structural materials and tecnology that the social requirements appropriately. Ductility of High Performance Fiber Reinforced cementitious Composites (HPFRCC), which exhibit strain hardening and multiple crackling characteristics under the uniaxial tensile stress are drastically improved. Because ductility in tensile test are very different according to specimen shapes, three types of the direct tensile test are performed. The tensile test are performed using the tensile test specimen, dummbell-shaped specimen, and cylinder specimen. As a result, tensile performance in HPFRCC is very good comparing to cylinder specimen because of direction characteristics of fibers. It is necessary to clarify the examination method of suiting to the usage.

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Size effect on strength of Fiber-Reinforced Self-Compacting Concrete (SCC) after exposure to high temperatures

  • Gulsan, M. Eren;Abdulhaleem, Khamees N.;Kurtoglu, Ahmet E.;Cevik, Abdulkadir
    • Computers and Concrete
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    • 제21권6호
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    • pp.681-695
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    • 2018
  • This pioneer study investigates the size effect on the compressive and tensile strengths of fiber-reinforced self-compacting concrete (FR-SCC) with different specimens, before and after exposure to elevated temperatures. 432 self-compacting concrete (SCC) specimens with two concrete grades (50 and 80MPa) and three steel fiber ratios (0%, 0.5% and 1%) were prepared and tested. Moreover, based on the experimental results, new formulations were proposed to predict the residual strengths for different specimens. A parametric study was also carried out to investigate the accuracy of proposed formulations. Residual strength results showed that the cylinder specimen with dimensions of $100{\times}200mm$ was the most affected, while the cube with a size of 100 mm maintained a constant difference with the standard cylinder ($150{\times}300mm$). Temperature effect on the cube specimen (150 mm) was the least in comparison to other specimen sizes and types. In general, provision of steel fibers in SCC mixtures resulted in a reduction in temperature effect on the variance of a conversion factor. Parametric study results confirm that the proposed numerical models are safe to be used for all types of SCC specimens.

콘크리트의 압축강도에 공시체의 크기와 형상이 미치는 영향 (Effect of Specimen Sizes and Shapes on Compressive Strength of Concrete)

  • 최중철;양은익;이성태;김명유;이광교
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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    • pp.285-288
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    • 2003
  • The compressive strength of concrete is used as the most fundamental and important material property when reinforced concrete structures are designed. It has been problem to use this value, however, because the control specimen sizes and shapes are different from every country. In this study, the effect of specimen shapes and sizes on compressive strength of concrete members was experimentally investigated based on fracture mechanics. Experiments for the mode I failure was earned out by using cylinder, cube, and prism specimens. The test results are curve fitted using least square method(LSM) to obtain the new parameters for the modified size effect law(MSEL). The analysis results show that the effect of specimen sizes and shapes on ultimate strength is apparent. The results also show stronger size effect in member when the casting direction is perpendicular to loading direction

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A treatise on irregular shaped concrete test specimens

  • Gorkem, Selcuk Emre
    • Computers and Concrete
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    • 제16권1호
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    • pp.179-190
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    • 2015
  • An experimental program has been carried out to investigate the effect of edge-slope on compressive strength of concrete specimens. In this study, effect of such slope was investigated by testing 100 standard cylinder specimens and 40 standard cubes. When molds are put on a slanted place, wet concrete starts to flow through the open end of mold. It keeps flowing until it reaches to a parallel surface with the place over which it was placed. That creates a sloped surface over the loading area. Experimental results revealed significant relationships between failure loads and slope of loading surface for cylinders. Angled cracks occurred in sloped cylinder specimens. Tension cracks occurred in cube specimens. Fracture mechanisms were also evaluated by using finite element analyses approach. Experiments yielded an exponential curve with bandwidth for cylinders. Average value of curve is $y={\frac{\pi}{2}}e^{-cf}$ between slope and compressive strength. Inclination is much effective parameter for cylinders than cubes.

환경조건에 따른 콘크리트의 중성화 특성 (The Effect of Environmental Conditions on Carbonation of Concrete)

  • 하재담;김태홍;유재상;이종열;정영수;배수호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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    • pp.175-180
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    • 2002
  • Regardless of the carbonation of concrete is one of the importants causes of corrosion of reinforing steel in concrete with the cloride attack and the frost damage, the investigacion about the carbonation of concrete is limited and each investigator experiments under different condition. In this paper, the effect of temperature, relative humidity, concentration of $CO_2$, type of specimen, etc., were investigated according to the accelerated carbonation test. The principal conclusions from this research were as follows: 1) The carbonation of concrete is higher in olden of, under environmental condition(temperature-relative humidity, concentration of $CO_2$, ) of 40-40-10>40-50-10>40-60-5>20-60-5. 2) Under same environmental condition, the carbonation of concrete in $\Phi$10$\times$20cm cylinder specimen is 2-8% higher then 10$\times$10$\times$40cm specimen.

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면진용 고강도 콘크리트 구의 할열강도 특성에 관한 연구 (A Study on the Split Strength Characteristics of High Strength Concrete Sphere for Seismic Isolation)

  • 김동백;김인배;김명곤;박봉관
    • 한국재난정보학회 논문집
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    • 제14권4호
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    • pp.466-473
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    • 2018
  • 연구목적: 최근에는 지진에 대한 안정성을 위해 면진 또는 면진과 내진을 병용하는 추세로 가고 있는데, 신축할 중 저층 RC 구조물에 콘크리트 구 기초(CSF)를 설치하는 형태의 시스템을 사용할 때 기초로 사용할 콘크리트 구의 할열특성을 파악하고자 한다. 연구방법: 압축강도 60Mpa인 고강도 콘크리트 구의 할열강도를 알기 위하여 다양한 실험을 수행하고, 표준 실린더 공시체의 할열강도에 대한 구 공시체의 할열강도 비 및 구의 직경변화에 따른 치수효과 등을 실험적으로 구하고자 한다. 연구결과: 150mm 구 공시체의 할열강도는 $150mm{\times}150mm$, $150mm{\times}300mm$의 원주형 공시체 보다 작을 것으로 예상했으나, 실험결과는 각각 3.8%, 13.7% 큰 4.39Mpa로 나타났는데 이는 구 공시체의 점하중과 원주형 공시체의 선하중에 대한 내력작용이 다르기 때문이라 판단된다. 결론: 원주형 공시체에 대한 할열 인장강도는 많은 연구가 진행되어 표준화된 방법이 있으나, 구 공시체의 할열강도에 대한 연구는 보고된 바가 거의 전무하여 본 연구에서는 직경 50mm~150mm의 할열강도 특성을 파악하고, 그 방법을 확립하여 콘크리트 구의 할열강도 및 관련 연구에 대한 기본 자료를 제공하고자 한다.

Effect of specimen geometry and specimen preparation on the concrete compressive strength test

  • Aslani, Farhad;Maia, Lino;Santos, José
    • Structural Engineering and Mechanics
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    • 제62권1호
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    • pp.97-106
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    • 2017
  • This paper discusses an experimental programme that was carried out to study the effects of specimen size-shape and type of moulds on the compressive strength of concrete. For this purpose, cube specimens with 150 mm dimensions, cylinder specimens with $150{\times}300mm$ dimensions, and prism specimens with $150{\times}150{\times}375mm$ dimensions were prepared. The experimental programme was carried out with several concrete compositions belonging to strength classes C20/25, C25/30, C30/37, C40/50 and C60/75. Furthermore, the test results were curve-fitted using the least squares method to obtain the new parameters for the modified size effect law.

콘크리트 압축강도 예측식의 일반화 및 이들 식의 검증 (Generalization and its Verification of Concrete Compressive Strength Prediction Equation)

  • 최중철;이성태;양은익;김동용;손석호;문병석
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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    • pp.537-540
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    • 2006
  • In previous study, the effect of specimen sizes and shapes on the compressive strength of concrete specimens was experimentally investigated based on fracture mechanics. In this study, the relationship between the cube compressive strength and the cylinder strength for representative specimen sizes was investigated by linear regression analyses. And, by reanalyzing the compressive strength prediction equations with specimen size and shape obtained in previous studies, the compressive strength prediction equations were generalized. In addition, its verification was investigated by comparing with the results obtained from other researchers.

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콘크리트 강도수준별 음향방출(Acoustic Emission)의 특성에 관한 연구 (A Study on the Characteristic of Acoutic Emission with Concrete Compressive Strength Level)

  • 이웅종;이종열;정연식;양승규;한상훈
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.789-794
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    • 2001
  • The acoustic emission(AE) signal from concrete cylinder specimen during failure process under cycling compressive loads were recorded and analyzed. Different filters were set on the AE signal duration based on the characteristic of amplitude distribution. From the value of AE signal amplitude, which corresponds to the occurrence of the peak for AE hits, the AE signals from concrete compressive specimen were divided into five sections. The relationship between the AE signal section and the failure mechanism of these materials, analyzed on the meso-structure level was determined. Based on the experiments, the AE characteristics of each failure mechanism are given. The results show that the AE technique is a valuable tool to study the failure mechanism of concrete.

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