• Title/Summary/Keyword: anisotropic tensile strength of concrete

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A new approach for measurement of anisotropic tensile strength of concrete

  • Sarfarazi, Vahab;Faridi, Hamid R.;Haeri, Hadi;Schubert, Wulf
    • Advances in concrete construction
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    • v.3 no.4
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    • pp.269-282
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    • 2015
  • In this paper, a compression to tensile load converter device was developed to determine the anisotropic tensile strength of concrete. The samples were made from a mixture of water, fine sand and cement, respectively. Concrete samples with a hole at its center was prepared and subjected to tensile loading using the compression to tensile load converter device. A hydraulic load cell applied compressive loading to converter device with a constant pressure of 0.02 MPa per second. Compressive loading was converted to tensile stress on the sample because of the overall test design. The samples have three different configurations related to loading axis; 0, $45^{\circ}$, $-45^{\circ}$. A series of finite element analysis were done to analyze the effect of hole diameter on stress concentration of the hole side along its horizontal axis to provide a suitable criterion for determining the real tensile strength of concrete. Concurrent with indirect tensile test, Brazilian test and three point loading test were also performed to compare the results from the three methods. Results obtained by this device were quite encouraging and show that the tensile strengths of concrete were similar in different directions because of the homogeneity of bonding between the concrete materials. Also, the indirect tensile strength was clearly lower than the Brazilian test strength and three point loading test.

Nonlinear finite element analysis of Concrete Filled Carbon Tube Columns Using Plasticity Theory (축하중을 받는 콘크리트 충전 탄소섬유튜브 기둥의 소성 이론을 적용한 비선형 유한요소해석)

  • Kim, Heecheul;Seo, Sang Hoon;Lee, Young Hak
    • KIEAE Journal
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    • v.7 no.6
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    • pp.119-126
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    • 2007
  • In the field of composite structures, the use of carbon tube for the confinement of concrete has been arisen since 1990's. However, experimental and analytical studies were limited to those of reinforced concrete and concrete filled steel tube. The carbon tube provides excellent confinement capabilities for concrete cores, enhancing compressive strength and ductility of concrete significantly. The carbon tube has high tensile strength, light weight, corrosion immunity and high fatigue strength properties. Since carbon fiber is an anisotropic material, carbon tube could be optimized by adjusting the fiber orientation, thickness and the number of different layers. In this study, both experimental and analytical studies of axial and lateral behavior of full-scale CFCT (Concrete Filled Carbon Tube) columns subjected to monotonic axial load were carried out using Drucker-Prager theory. And, based on comparison results between experiment results and analytical results, k factor estimation was proposed for effective analysis.

Plasticity Model for Directional Nonlocal Crack Damage of Concrete (콘크리트의 방향적 비국소 균열 손상을 위한 소성모델)

  • Kim Jae-Yo;Park Hong-Gun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.914-921
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    • 2006
  • To describe the effect of the numerous and various oriented microcracks on the compressive and tensile concrete behaviors, the directional nonlocality is defined. The plasticity model using multiple failure criteria is developed for RC planar members in tension-compression. The crack damages are defined in the pre-determined reference orientations, and then the total crack damage is calculated by integrating multi-oriented crack damages. To describe the effect of directional nonlocality on the anisotropic tensile damage, based on the existing test results, the nonlocal damage factor is defined in each reference orientation. The reduced compressive strength in the cracked concrete is defined by the multi-oriented crack damages defined as excluding the tensile normal plastic strain from the compressive equivalent plastic strain. The proposed model is implemented to finite element analysis, and it is verified by comparisons with various existing panel test results.

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