scholarly journals Experimental Study of Rubberized Concrete Stress-Strain Behavior for Improving Constitutive Models

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2245 ◽  
Author(s):  
Kristina Strukar ◽  
Tanja Kalman Šipoš ◽  
Tihomir Dokšanović ◽  
Hugo Rodrigues
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Curve ◽  
Experimental Results ◽  
Nonlinear Material ◽  
Rubberized Concrete ◽  
Rubber Content ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Failure Patterns

Inclusion of rubber into concrete changes its behavior and the established shape of its stress-strain curve. Existing constitutive stress-strain models for concrete are not valid in case of rubberized concrete, and currently available modified models require additional validation on a larger database of experimental results, with a wider set of influential parameters. By executing uniaxial compressive tests on concrete with rubber substituting 10%, 20%, 30%, and 40% of aggregate, it was possible to study and evaluate the influence of rubber content on its mechanical behavior. The stress-strain curve was investigated in its entirety, including compressive strength, elastic modulus, strains at significant levels of stress, and failure patterns. Experimental results indicated that increase of rubber content linearly decreases compressive strength and elastic modulus, but increases ductility. By comparing experimental stress-strain curves with those plotted using available constitutive stress-strain models it was concluded that they are inadequate for rubberized concrete with high rubber content. Based on determined deviations an improvement of an existing model was proposed, which provides better agreement with experimental curves. Obtained research results enabled important insights into correlations between rubber content and changes of the stress-strain curve required when utilizing nonlinear material properties.

The Research of Test on Stress-Strain Constitutive Relations of Straw Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 987-992
Author(s):  
Wei Liu ◽  
Wei Xi ◽  
Yi Lu Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Constitutive Relations ◽  
Strain Curve ◽  
Green Building ◽  
Corn Straw ◽  
Stress Strain Curve ◽  
Stress Strain

As a new green building material, straw concrete are introduced about its mechanical properties and characteristics. Mechanical properties test such as prism compressive strength, elastic modulus and Poisson's ratios use standard prismatic blocks. Under different rate of corn straw, cement, sand and fly ash, test gets the full stress-strain curve. Results show that with increase of volume of corn straw, the prism compressive strength reduces significantly. Comparing with natural concrete, elastic modulus of straw concrete can reduces greatly. Poisson’s ratio reduces with increase of volume of corn straw. Fly ash could improve property of the material and replace cement, but excessive replacement will reduce the strength of material.

scholarly journals Experimental Study on Damage and Failure of Coal-Pillar Dams in Coal Mine Underground Reservoir under Dynamic Load

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Qiangling Yao ◽  
Liqiang Yu ◽  
Ning Chen ◽  
Weinan Wang ◽  
Qiang Xu
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Water Content ◽  
Dynamic Loading ◽  
Coal Pillar ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Underground Reservoir

The stability of coal-pillar dams in underground hydraulic engineering works is affected not only by long-term water erosion but also by dynamic loading induced, for example, by roof breaking or fault slipping. In this paper, the water absorption characteristics of coal samples from western China were studied by nondestructive immersion tests, and a high-speed camera was used to monitor SHPB tests on samples of varying water content and subjected to various strain rates. Besides, the coal-pillar dam is numerically simulated based on the experimental data and the actual engineering conditions. The results show that, given low strain rate and high water content, the compaction stage accounts for most of the stress-strain curve, whereas the elastic stage accounts for only a relatively small fraction of the stress-strain curve. The dynamic compressive strength and elastic modulus follow exponential and logarithmic functions of strain rate, respectively, exhibiting a significant positive correlation. As the water content increases, the dynamic elastic modulus increases almost linearly, and the compressive strength decreases gradually. Under the same impact load, samples with greater water content fail more rapidly, and the failure is exacerbated by the propagation of parallel cracks to staggered cracks. The average size of coal fragments decreases linearly with increasing strain rate and water content. Simulations indicate that dynamic loading increases the stress concentration on both sides of the dam and expands the high-stress area and plastic zone. The results provide guidance for designing waterproof coal pillars and underground reservoir dams.

scholarly journals Evaluasi Blok Tegangan Tekan Ekuivalen Balok Beton Bertulang Agregat Limbah Batu Onyx Tulungagung

2021 ◽  
Vol 15 (1) ◽  
pp. 45-50
Author(s):  
Bobby Asukmajaya R. ◽  
◽  
Edhi Wahjuni S. ◽  
Wisnumurti Wisnumurti ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Average Compressive Strength ◽  
Stress Block

Normal aggregate replacement to the onyx waste aggregate will certainly make the compressive strength and modulus of elasticity different, so it will affect the value of the compressive stress block equivalent (β1) as a result of the extent of the changing stress strain curve. In this study, trying to compare between the experimental β1 value of onyx concrete, while analytically the β1 value for normal concrete was obtained in accordance with SNI 2847 - 2019. To get the experimental β1 value from onyx concrete, it is made by looking for the compressive strength, elastic modulus and ꜫ0, for later the stress strain curve of the concrete is made to find the experimental β1 value of the onyx concrete. The results were obtained if the average β1 value of 18 specimens of onyx coarse aggregate concrete with an average compressive strength of 32.92 MPa was 0.868 while the analytical β1 value based on SNI 2847-2019 was 0.839, This shows that the B1 value for concrete with other aggregates is different, so it needs to be checked experimentally.

scholarly journals Study on The Mechanical Properties of Steel - Basalt Fiber Composite Reinforcement (SBFCBs)

2020 ◽  
Vol 165 ◽  
pp. 05028
Author(s):  
Lei Zhao ◽  
Shengjiang Sun ◽  
Wei Qi
Keyword(s):  
Elastic Modulus ◽  
Fiber Composite ◽  
Low Cost ◽  
Basalt Fiber ◽  
Strain Curve ◽  
Tensile Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Failure Patterns ◽  
Steel Bars

Steel bar and Basalt Fiber are combined to obtain a new structural material with high strength, high elastic modulus, high toughness, corrosion resistance, low cost and other excellent comprehensive performance: Steel Basalt Fiber Composite Bars (SBFCBs). In this paper, three different types of composite bars were tested by monotonic tensile tests, and the failure patterns of steel bars were introduced in the process of stretching, and the yield strength, ultimate strength, elastic modulus and stress-strain curves of steel bars were obtained. Test results showed that the stress-strain curve of SBFCBs was obviously double-folded, and SBFCBs exhibited stable post-yielding stiffness after the reinforcement yielded. The stress-strain curve model of SBFCBs under uniaxial tension was derived according to the material’s compounding rule. By sorting the experimental data and comparing it with theoretical values, we could prove the accuracy of the model.

scholarly journals Elastic modulus and stress-strain curve analysis of a tungsten mine waste alkali-activated concrete

2019 ◽  
Vol 274 ◽  
pp. 02003
Author(s):  
Pedro Silva Humbert ◽  
João Paulo De Castro Gomes ◽  
Luis Filipe Almeida Bernardo ◽  
Clemente Martins Pinto ◽  
Natalia Paszek
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Raw Materials ◽  
Mine Waste ◽  
Strain Curve ◽  
Portland Cement Concrete ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Glass Waste ◽  
Tungsten Mine

In the paper the compressive strength, the elastic modulus and the stress-strain curve of an alkaliactivated concrete were studied. A tungsten mine waste mud (TMWM), aggregate (also from the tungsten mine), glass waste and metakaolin were used as raw materials. Sodium silicate and sodium hydroxide were used as activators. First, TMWM chemical composition was determined by scanning electron microscopyenergy dispersive spectroscopy (SEM-EDS). The maximum particle size was 18mm. Two cubes with side dimension of 15cm were prepared from the mixture. Samples were cured at 60°C for 24 hours. A concrete mixer, vibration table and an oven were used in the process. After the curing process, cubes were cut into seven prisms and one cube with the dimensions 15x7.4x7.4cm and 7.4cm respectively. After 28 days, the laboratory tests were performed. During the compressive strength tests, the displacements were also recorded which allowed drawing the stress-strain curve of the samples. The compressive strength ranged from 17.27 to 28.84MPa. The elastic modulus was calculated by four different standards: ASTM, LNEC and European standard. The elastic modulus ranged from 2.48 to 7.49GPa what showed that the material is more elastic than ordinary Portland cement concrete.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

Fracture Assessment of Pipes Having Multiple Flaws Based on Ramberg–Osgood-Type Stress–Strain Relationships

2011 ◽  
Author(s):  
Hideo Machida ◽  
Tetsuya Hamanaka ◽  
Yoshiaki Takahashi ◽  
Katsumasa Miyazaki ◽  
Fuminori Iwamatsu ◽  
...  
Keyword(s):  
Flow Stress ◽  
Stress Concentration ◽  
Fracture Strength ◽  
Strain Curve ◽  
Assessment Method ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Relationship ◽  
Fracture Assessment

This paper describes a fracture assessment method for a pipe having multiple circumferential flaws. According to Fitness-for-Service (FFS) codes for nuclear facilities published by the Japanese Society of Mechanical Engineers (JSME), the fracture strength of a high-ductility pipe having a circumferential flaw is evaluated using the limit load assessment method assuming the elastic–perfectly-plastic stress–strain relationship. In this assessment, flow stress is used as a proportional stress. However, previous experimental results [1, 2, 3] show that a crack penetrates before the entire flawed pipe section reaches the flow stress. Therefore, stress concentration at a flaw was evaluated on the basis of the Dugdale model [4], and the fracture strength of the crack-ligament was evaluated. This model can predict test results with high accuracy when the ligament fracture strength is assumed to be tensile strength. Based on this examination, a fracture assessment method for pipes having multiple flaws was developed considering the stress concentration in the crack-ligament by using the realistic stress–strain relationship (Ramberg–Osgood-type stress–strain curve). The fracture strength of a multiple-flawed pipe estimated by the developed method was compared with previous experimental results. When the stress concentration in the crack-ligament was taken into consideration, the fracture strength estimated using the Ramberg–Osgood-type stress–strain curve was in good agreement with experimental results, confirming the validity of the proposed method.

Research on Compressive Deformation Characters of Mortar-Free Grouted Concrete Masonry

2014 ◽  
Vol 1004-1005 ◽  
pp. 1531-1536 ◽  
Author(s):  
Xi Xi He ◽  
Ye Lin
Keyword(s):  
Elastic Modulus ◽  
Compressive Stress ◽  
Test Data ◽  
Strain Curve ◽  
Compressive Deformation ◽  
Filling Rate ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Concrete Masonry

Compressive experiments on mortar-free grouted concrete masonry composed with hollow blocks were studies in this essay. Characteristics of compressive stress-strain curve were analyzed by utilizing test data of 15 specimens with 100% filling rate of grouted concrete. Further more, elastic modulus formula was proposed according to results of previous and present work.

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