scholarly journals Influence of Specimen Size and Shape on the Uniaxial Compressive Strength Values of Rocks

2021 ◽  
Author(s):  
Tatiana Durmeková ◽  
Martin Bednarik ◽  
Petra Dikejová ◽  
Renáta Adamcová
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Specimen ◽  
Slenderness Ratio ◽  
Factors Affecting ◽  
Size And Shape ◽  
Strength Tests ◽  
Ucs Test ◽  
Variable Impact ◽  
Significant Factors

Abstract The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test are the size, slenderness ratio h/d (ratio of height to diameter), and the shape of the rock specimen. The proposed experimental study shows the variable impact of these parameters on UCS values by implementing several lithological types. Standard strength tests were performed on four lithological types: granodiorite, limestone, sandstone and andesite. Cylindric and cube-shaped test specimens of different sizes were prepared from each rock. Cylindric specimens with diameter 20 mm, 35 mm, 50 mm and 70 mm with height to diameter ratio of 1:1 and 2:1, and cubic and prismatic specimens with an edge dimension of 50 mm were tested and analyzed. Obtained results of strength tests confirmed a high variability of current research opinions on how the size and shape of specimens influence the strength values of rocks. The study revealed the impossibility of conclusive correlations between the UCS and specimens to be generally applicable for all lithological types. Of the observed effects on the strength, the aspect of the specimen slenderness ratio was the most pronounced on all studied rocks.

EFFECT OF PETROLOGICAL FEATURES ON MECHANICAL PROPERTIES OF ROCK SALT FROM THE LGOM (LEGNICA–GŁOGÓW COPPER DISTRICT)

2016 ◽  
pp. 51-64 ◽  
Author(s):  
Katarzyna CYRAN ◽  
Tomasz TOBOŁA ◽  
Paweł KAMIŃSKI
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Salt ◽  
Fluid Inclusions ◽  
Mechanical Parameters ◽  
Research Results ◽  
Strength Tests ◽  
Crystal Boundaries

The paper presents the attempt to find a correlation between the content of impurities and mechanical parameters of rock salt from the LGOM. Research was carried out in three steps: uniaxial compressive strength tests, determination of the content of insoluble minerals (impurities), and observations under the microscope and Raman microspectroscopy. The research results reveal that the rock salt which is characterized by low content of insoluble minerals (0.13–2.11% wt.) shows no correlation between the mechanical properties and the content of impurities. However, it was found that mechanical properties depend on both the distribution of impurities in halite crystals and the presence of fluid inclusions and hydrocarbons along the crystal boundaries. Moreover, the distribution of anhydrite at the edges of halite crystals may influence an increase of rock salt strength. On the contrary, the presence of fluid inclusions and hydrocarbons along the halite crystal boundaries may reduce the rock salt strength.

scholarly journals RESISTÊNCIA A COMPRESSÃO EM TESTEMUNHO DE CONCRETO: INFLUÊNCIA DO FATOR DE ESBELTEZ, DIÂMETRO DA AMOSTRA E MÉTODO DE EXTRAÇÃO

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Marcelo Henrique Farias de Medeiros ◽  
Ana Paula Brandão Capraro ◽  
Giovana Costa Réus ◽  
Marcel Luiz Escobedo
Keyword(s):  
Compressive Strength ◽  
Slenderness Ratio ◽  
Extraction Procedure ◽  
Resistance Level ◽  
Curing Conditions ◽  
Standard Specimens ◽  
Strength Tests ◽  
Axial Compressive Strength ◽  
The Difference ◽  
Shape Ratio

RESUMO: Este trabalho tem como objetivo avaliar a influência dos fatores de forma nos ensaios de resistência à compressão em testemunhos de concreto. Para isso foram moldadas e extraídas amostras de concreto de 20 e 30 MPa. Variou-se o diâmetro da base das amostras (50 e 100mm) e sua esbeltez (de 1 a 3). Para verificar a diferença entre amostras moldadas e extraídas, no momento da fabricação do concreto foram moldados corpos de prova de 100 x 200 mm e dois blocos de 500 x 630 x 270 mm de onde os testemunhos foram extraídos. Os dados indicam que os valores de resistência à compressão obtidos em testemunhos de 50 mm de diâmetro tenderam a ser mais baixos do que os obtidos com 100 mm. A magnitude desta diferença é afetada pelo nível de resistência do concreto avaliado. Além disso, a resistência dos testemunhos extraídos foi menor ou igual à obtida em corpos de prova moldados, mesmo mantendo as condições de cura constantes entre o bloco e os corpos de prova normalizados. Dessa forma, o que pode ser concluído neste estudo é que, a resistência real da estrutura é minorada pelo procedimento da extração, sendo este influenciado por diversos fatores. Dentre as possíveis variáveis da extração, o diâmetro foi um fator que demonstrou influência significativa na propriedade do material ensaiado
 
 ABSTRACT: This study aims to evaluate the influence of shape ratio in compressive strength tests. Concrete specimens with 20 and 30 MPa was made and extracted. The diameter of the specimen’s base was 50 and 100mm and its slenderness ratio vary 1 to 3. To verify the difference between molded and samples taken at the time of manufacture of concrete molded bodies were evidence of 100 x 200 mm and two blocks of 500 x 630 x 270 mm where witnesses were extracted. The results indicated that the axial compressive strength values obtained with concrete cores extracted of 50 mm diameter tended to be lower than those obtained with 100 mm, and the magnitude of this difference is affected by the resistance level of the evaluated concrete. Furthermore, the resistance of concrete cores extracted was less than or equal to the obtained in the molded test specimens, while maintaining constant the curing conditions between the block and standard specimens. Thus, it can be concluded in this study is that the real strength of the structure is alleviated by the extraction procedure, which is influenced by several factors. Among the possible variables of extraction, the diameter was a factor that showed a significant influence on the property of the material tested.

Influence of Loading Rate on Uniaxial Compression Test of Rock Specimen with Random Joints

2011 ◽  
Vol 396-398 ◽  
pp. 217-220
Author(s):  
Bing Xie ◽  
Jin Jun Guo ◽  
Xiang Xia
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Compression Test ◽  
Rock Specimen ◽  
Loading Rate ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Uniaxial Compression Test ◽  
Compression Tests

Numerical specimens with ramdom joints is established by particle flow code PFC2D and uniaxial compression tests are conducted under three different loading rate. Studies have shown that strength of uniaxial compression are all increased with the loading rate no matter what specimen is complete or with random joints. The sensitivity of changes of uniaxial compressive strength of specimen with random joints decreases with increasing of the loading rate.

scholarly journals Stiffness and Strength of Granular Soils Improved by Biological Treatment Bacteria Microbial Cements

2018 ◽  
Vol 2 (4) ◽  
Author(s):  
Mehdi Jalili ◽  
Mohmad Reza Ghasemi ◽  
Ali Reza Pifloush
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Soil Improvement ◽  
Granular Soils ◽  
Industrial Town ◽  
Strength Tests ◽  
Problematic Soils ◽  
Strength And Stiffness

In some parts of the world mechanical properties of problematic soils are not suitable for construction purposes. Today, regard to the importance of the soil improvement; by considering methods with more concordance with the environmental mechanisms in the nature, and with study and combination of geotechnical science, microbiology and geochemistry; researchers try to provide a suitable way to improve the physical and mechanical properties of the problematic soils. In this paper, the effect of the aerobic microorganisms of Sporosarsina Pasteurii (PTCC 1645), as a producer of Urease for the sedimentation of calcium carbonate and improvement of granular soil of Garmsar Industrial Town is evaluated experimentally in order to check the effects of this phenomena on the shear strength and stiffness of the granular soils. The results of the uniaxial compressive strength tests show the effect of adding the above mentioned microbial solution to the soils, in case of increased uniaxial compressive strength and stiffness of the soil. It should be mentioned that the granular soils have no compressive strength, naturally but after bio cementation the samples got notable values.

A Review Paper on Specimens Size and Shape Effects on the Concrete Properties

2018 ◽  
Vol 5 (3) ◽  
Author(s):  
Ola Adel Qasim
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Concrete Strength ◽  
Shape Effect ◽  
Conversion Factors ◽  
Factors Affecting ◽  
Size And Shape ◽  
Concrete Properties ◽  
Shape Effects ◽  
Concrete Cube

Concrete properties are the most essential and critical physical material property when reinforced concrete structures are planned. Because of the development and in types and nature of material used to enhance the concrete innovation, materials and mix proportions, test measure, mixing strategy, and testing condition have noteworthy impacts on highlights of concrete strength, in light of the fact that the control specimen sizes and shapes might be unique in relation from State to State. Testing of mechanical properties (especially compressive strength and tensile strength) of concrete is one of the most urgent stages of development. To control the nature of the concrete, there are different molds used for pouring concrete samples according to different directions in different countries. Many researchers have realized that the specific shapes and sizes of concrete samples can cause different types in the consequences of compressive strength or tensile strength. The relationship between the compressive strength of the concrete cube and the cylinder is complex. The cylinder and concrete cube samples were compared in the pressure test by studying previous research, including the test methodology, factors affecting the cylinder / cube strength ratio, and the coefficients, equations and components of the conversion factors. Previous attempts to determine experimental transformational relationships and conversion factors have proved that it is disturbing (if not impossible) to predict the relationships between the forces of the cylinder and the cube. Previous research has shown that the ratio of the strength of the cylinder / cube is between 0.65 and 0.90, despite the fact that the ratios outside this range have been found similarly. In light of this review of previous research, the test of the cylinder is not initiated by testing the cube. This study is a review of the sample size and shape effect on concrete properties.

scholarly journals Influencing Factors for the Instability and Collapse Mode of the Goaf Structure in a Gypsum Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhaowen Du ◽  
Zhihe Liu ◽  
Rui Liu ◽  
Sheng Wang ◽  
Faxin Li
Keyword(s):  
Compressive Strength ◽  
Water Temperature ◽  
Failure Mechanism ◽  
Influencing Factors ◽  
Uniaxial Compressive Strength ◽  
Large Area ◽  
Multiple Factors ◽  
Collapse Mode ◽  
Strength Tests ◽  
Gypsum Rock

Large-area goafs in a gypsum mine tend to collapse after 10 or more years, but the influencing factors are still unclear, and the effects of multiple factors have not been comprehensively considered. In this study, the failure mechanism and collapse mode of the room-pillar goaf structure were analyzed, and the uniaxial compressive strength tests of the pillars under different conditions were carried out in a laboratory. The influences of water, temperature, and time on the strength of the gypsum rock were considered. These three factors weakened the gypsum rock in different degrees. After 120 days of immersion, water had the greatest effect with a strength-weakening rate of 52.61%. After 20 temperature cycles, changes in temperature had little effect with a strength-weakening rate of 12.60%. After 25 years of aging, the strength-weakening rate of time was 25.13%. These results show how different factors affect the instability and collapse of the goaf structure, which are of great significance for predicting and preventing this from happening.

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