• Title/Summary/Keyword: split tensile test

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Development of Model Equations for Strength Properties with Age in Concrete Pavement (재령에 따른 포장용 콘크리트의 강도특성 예측식 개발)

  • Yang, Sung-Chul;Kwon, Su-Ahn;Lim, Yu-Jin
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.35-43
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    • 2010
  • This study was carried out to find reliable relations between various concrete strength properties which are used as input data in concrete pavement design program. Concretes were made from different sources of coarse grained(granite, limestone and sandstone) and fine grained aggregates such as natural sand, washed sand and crushed sand. From strength test results, model equations were obtained based on the relation between strengths. For each coarse grained aggregate, models for compression-flexural strengths, compression-split tensile strengths, compressive strength-modulus and flexural-split tensile strengths with age were obtained. For concrete mixed with gneiss granite aggregates, concrete strengths were obtained from numerical mean values of concrete strengths mixed with fine grained aggregates. In addition models for concrete split tensile strengths and modulus values were provide by averaging numerically the estimated values obtained from the derived relationship and the experimental values. This is due to more scattered values of split tensile strengths and modulus values than other strength properties. Finally criteria for drying shrinkage strain as well as Poisson's ratio for concrete used in pavement were presented for all mixes with differed coarse grained aggregates.

Estimation of Dynamic Brazilian Tensile Strengths of Rocks Using Split Hopkinson Pressure Bar (SHPB) System (스플릿 홉킨슨 압력봉 실험장비를 이용한 암석의 동적 압열인장강도 평가에 관한 연구)

  • Yang, Jung-Hun;Ahn, Jung-Lyang;Kim, Seung-Kon;Song, Young-Su;Sung, Nak-Hoon;Lee, Youn-Kyou;Cho, Sang-Ho
    • Tunnel and Underground Space
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    • v.21 no.2
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    • pp.109-116
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    • 2011
  • In this study, we estimated the dynamic tensile strength and strain rate from Brazilian tensile test using Split Hopkinson Pressure Bar (SHPB) system. A pulse shaping technique, which controls the shape of the impactinduce incident waves, was used for achieving the dynamic stress equilibrium and constant strain rate before fracture of rock samples. Three kinds of rock type, Inada granite, Kimachi sandstone and Tage tuff were prepared as 50mm in diameter and 26 mm in thickness. The high-speed videography system was used to observe the fracture processes of the rock samples. As the results of the tests, the ratio of dynamic tensile strength and static tensile strength was 11.9 for Inada granite, 8.5 for Kimachi sandstone and 9.2 for Tage tuff.

The Relationship between Splitting Tensile Strength and Compressive Strength of Fiber Reinforced Concretes

  • Choi, Yeol;Kang, Moon-Myung
    • Journal of the Korea Concrete Institute
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    • v.15 no.1
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    • pp.155-161
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    • 2003
  • This paper presents experimental and analytical results of glass fiber-reinforced concrete (GFRC) and polypropylene fiber-reinforced concrete (PERC) to investigate the relationship between tensile strength and compressive strength based on the split cylinder test (ASTM C496) and compressive strength test (ASTM C39). Experimental studies were performed on cylinder specimens having 150 mm in diameter an 300 mm in height with two different fiber contents (1.0 and 1.5% by volume fraction) at ages of 7, 28 and 90 days. A total of 90 cylinder specimens were tested including specimens made of the plain concrete. The experimental data have been used to obtain the relationship between tensile strength and compressive strength. A representative equation is proposed for the relationship between tensile strength and compressive strength of fiber-reinforced concrete (FRC) including glass and polypropylene fibers. There is a good agreement between the average experimental results and those calculated values from the proposed equation.

Tensile Strength Characteristics of Steel Cord and PVA Hybrid Fiber Reinforced Cement-Based Composites (Steel Cord와 PVA 혼합섬유 보강 고인성 시멘트 복합체의 인장강도 특성)

  • Yun Hyun Do;Yang Il Seung;Han Byung Chan;Hiroshi Fukuyama;Cheon Esther;Moon Youn Joon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.18-21
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    • 2004
  • This paper discusses how steel cord and PVA hybrid fibers enhance the performance of high performance fiber reinforced cementitious composites (HPRFCC) in terms of elastic limit, strain hardening response and post peak of the composites. The effect of microfiber(PVA) blending ratio is presented. For this purpose flexure, direct tension and split tension tests were conducted. It was found that HFRCC specimen shows multiple cracking in the area subjected to the greatest bending tensile stress. Uniaxial tensile test confirms the range of tensile strain capacity from 0.5 to $1.5\%$ when hybrid fiber is used. The cyclic loading test results identified a unique unloading and reloading response for this ductile composite. Cyclic loading in tension appears not to affect the tensile response of the material if the uniaxial compressive strength during loading is not exceeded.

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Formula to identify the Influence of steel fibres on the mechanical properties of HPC

  • Philip, Nivin;Anil, Sarah
    • Computers and Concrete
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    • v.25 no.5
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    • pp.479-484
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    • 2020
  • This work performed to analyses the impact of hooked end steel fibres on the mechanical properties of high performance concrete. The mechanical properties considered incorporate compressive strength, split tensile strength and flexural strength. Taking in to thought parameters, such as, volume fraction of fibres, fibre aspect ratio and grade of concrete, a logical strategy called Taguchi technique was utilized to discover the ideal blend of factors. L9 Orthogonal Array (OA) of Taguchi network comprising of three variables and three dimensions is utilized in this work. The evaluations of concrete considered were M60, M80 and M100. M60 contained 15% of metakaolin as bond swap though for M80 it was 5% of metakaolin and for M100 it was 10% metakaolin and 10% of silica smolder. The volume portion of fiber was fluctuated by 0.5%; 1% and 1.5% and the viewpoints proportions considered were 50, 60 and 80. The test outcomes demonstrate that incorporation of steel fibres enhance significantly the the strength characteristics of concrete, predominantly the splitting tensile strength and flexural strength. In light of relapse investigation of the test information scientific models were produced for compressive strength, split tensile strength and flexural strength of the steel fibre-reinforced high performance concrete.

Study on the Split Hopkinson Pressure Bar Apparatus for Measuring High-strain Rate Tensile Properties of Plastic Material (플라스틱 소재의 고 변형률 인장특성 평가를 위한 홉킨스바(Split Hopkinson Pressure Bar) 측정 장비에 관한 연구)

  • Han, In-Soo;Lee, Se-Min;Kim, Kyu-Won;Kim, Hak-Sung
    • Composites Research
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    • v.35 no.3
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    • pp.196-200
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    • 2022
  • Split Hopkinson Pressure Bar (SHPB) is a general test equipment for measuring the mechanical properties of high modulus metal and composite materials at high strain rate. However, for the soft plastic material, it is difficult to hold the specimen and achieve dynamic stress equilibrium due to the weak transmitted signals. In this study, SHPB test apparatus were designed to measure accurately the high strain rate stress-strain curve of the soft plastic materials by changing the incident bar materials and the shape of the specimen holder parts. In addition, to verify the high strain-rate tensile strain data obtained from SHPB, the strain distribution of the specimen was measured and analyzed with a high-speed camera and the digital image correlation (DIC), which was compared with the strain history measured from SHPB.

High strain rate tensile test of sheet metals with a new tension split Hopkinson bar (박판의 고변형률에서의 기계적특성을 얻기위한 Tension Split Hopkinson bar의 제작 및 실험)

  • Jung, Dong-Taek;Huh, Hoon;Kang, Woo-Jong;Cho, Sang-Soon
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.106-110
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    • 1997
  • A split Hopkinson bar has been used for obtaining material properties in high strain rate state, In this paper, the apparatus was modified to obtain the high strain rate properties of sheet metal for an autobody. From the experiments with the new apparatus, the material properties of SPCEN in the high strain rate state have been acquired and compared with quasi-static experimental results.

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Evaluation of mechanical properties for high strength and ultrahigh strength concretes

  • Murthy, A. Ramachandra;Iyer, Nagesh R.;Prasad, B.K. Raghu
    • Advances in concrete construction
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    • v.1 no.4
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    • pp.341-358
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    • 2013
  • Due to fast growth in urbanisation, a highly developed infrastructure is essential for economic growth and prosperity. One of the major problems is to preserve, maintain, and retrofit these structures. To meet the requirements of construction industry, the basic information on all the mechanical properties of various concretes is essential. This paper presents the details of development of various concretes, namely, normal strength concrete (around 50 MPa), high strength concrete (around 85 MPa) and ultra high strength concrete (UHSC) (around 120 MPa) including their mechanical properties. The various mechanical properties such as compressive strength, split tensile strength, modulus of elasticity, fracture energy and tensile stress vs crack width have been obtained from the respective test results. It is observed from the studies that a higher value of compressive strength, split tensile strength and fracture energy is achieved in the case of UHSC, which can be attributed to the contribution at different scales viz., at the meso scale due to the fibers and at the micro scale due to the close packing of grains which is on account of good grading of the particles. Micro structure of UHSC mix has been examined for various magnifications to identify the pores if any present in the mix. Brief note on characteristic length and brittleness number has been given.

The Comparative Analysis on Mechanical Property Test of Carbon Nanotube-based Shock Absorbers (탄소나노튜브를 기반으로 하는 충격흡수제의 물리적 특성 비교분석)

  • Kim, Jong-Woo;Chae, Woen-Sik
    • Korean Journal of Applied Biomechanics
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    • v.22 no.2
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    • pp.237-242
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    • 2012
  • The purpose of this study was (a) to develop carbon nanotube-based shock absorbers for reducing potentially harmful impact forces and excessive foot pronation, and (b) to briefly determine how the effects of carbon nanotube-based shock absorbers on biomechanical variance during drop landing. A university student(age: 24.0 yrs, height: 176.2 cm, weight: 679.5 N) who has no musculoskeletal disorder was recruited as the subject. Hardness, specific gravity, tensile strength, elongation, 100% modulus, tear strength, split tear strength, compression set, resilience, vertical GRF, and loading rate were determined for each material. For each dependent variable, a descriptive statistics was used for different conditions. The property test results showed that tensile strength, tear strength, split tear strength, compression set, and resilience in carbon nanotube-based shock absorbers were greater than general Ethylene Vinyl Acetate(EVA). These indicated that resistance against variable strength in developed carbon nanotube-based shock absorbers were greater than general EVA. In vertical GRF of CNTC was less than those of EVA during drop landing and loading rate of CNTC was greater than EVA. It seems that the use of CNT can be a effective way of reducing and controlling shock from impact.

High-Strain-Rate Deformation of Fe-6.5wt.%Si Alloys using a Split Hopkinson Pressure Bar Technique (홉킨슨 압력봉법을 이용한 Fe-6.5wt.%Si 합금의 고변형률속도 거동)

  • Yoon, Young-Ki;Yoon, Hi-Seak;Umakoshi, Yukichi;Yasuda, Hiroyuki Y.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.7
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    • pp.1073-1081
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    • 2001
  • Many researches have published numerous papers about the high-strain-rate obtained from Split Hopkinson Pressure Bar(SHPB) tests. And 6.5wt%Si steel is widely known as an excellent magnetic material because its magnetostriction is nearly zero. Single crystals are prepared by the Floating Zone(FZ) method, which melts the alloy by the use of a high temperature electron beam in a pure argon gas condition. In this paper, the fracture behavior of the poly crystals and single crystals (DO$_3$phase) of Fe-6.5wt%Si alloy by SHPB test is observed. The comparison of high-strain-rate results with static results was done. Obtained main results are as follows: (1) Fe-6.5wt%Si alloy has higher strength at high-strain-rate tensile. SHPB results of polycrystal are twice as high as static results. (2) From the fractography, the cleavage steps are remarkably reduced in the SHPB test compared with the static test.