scholarly journals CHANGES IN THE COMPOSITION AND PROPERTIES OF THE HOST ROCKS OF COAL DEPOSITS IN YAKUTIA UNDER THE INFLUENCE OF CRYOGENESIS

2020 ◽  
Vol 5 (443) ◽  
pp. 133-140
Author(s):  
Melnikov Andrey E., ◽  
◽  
Ze Zhang, ◽  
Grib Nikolay N., ◽  
Camil Jakub Shabo, ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Great Influence ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Physicomechanical Properties ◽  
Freezing And Thawing ◽  
Coal Deposits ◽  
Host Rocks ◽  
Transformation Processes ◽  
Cryogenic Processes

The results of laboratory tests carried out on rock samples of the Kharbalakhskoye coalfield located in Central Yakutia revealed significant secondary changes having taken place in the host rocks containing the coal. Evidently, under transformation processes, it is not only the composition of the rocks that had changed, but also the nature of structural bonds that have a great influence on their physical and mechanical properties. Thus, the ultimate strength values of coal-containing sandstone and siltstone samples under uniaxial compression vary from 20 to 30 MPa, while under uniaxial tension, the ultimate strength values range from 6 to 10 MPa. These relatively low numerical values pertaining to the physicomechanical properties of rocks, which are generally atypical for long-flame coal deposits, are almost 50% lower than those of analogous rocks hosting other coal deposits in Russia. It is considered that the mechanical strength properties of the rocks of the Kharbalakhskoye field are due to significant cryogenic processes. A comparative analysis of the properties of core samples obtained from boreholes drilled in 2019 with samples from a quarry obtained several decades ago reveals signs of transformation of rocks in the Kharbalakhskoye field due to phase transitions of freezing and thawing water.

scholarly journals Concrete based on sulfur binder being modified with inorganic additives

2018 ◽  
Vol 212 ◽  
pp. 01013
Author(s):  
Vadim Balabanov ◽  
Victor Baryshok ◽  
Nikita Epishkin
Keyword(s):  
Frost Resistance ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Strength Properties ◽  
Climatic Conditions ◽  
Freezing And Thawing ◽  
Concrete Mixtures ◽  
Irkutsk Region ◽  
Water Saturated

The sharply continental climate of the Irkutsk region is characterized by wide temperature intervals throughout the year. The repeated cyclicity of freezing and thawing of building materials in the water-saturated state influences the change in technical characteristics and the durability of concrete products and structures. The concrete products’ features in such climatic conditions create the need for the production of concretes with improved indicators of physical and mechanical properties. The effect of modifying additives on the technological characteristics of sulfur concrete is established. The effect of all elements of sulfur concrete on its strength and frost resistance. The composition of sulfuric concrete is obtained, which meets all the requirements and also has high strength and increased frost resistance. Formulations with a certain ratio of structural sulfuric concrete mixtures were developed. As a result of the use of technical sulfur in the composition of concrete products, the problem of utilizing annually accumulating reserves of technical sulfur is partially solved. The strength properties of sulfuric concretes easily compete with high-quality brands of concrete, special types of concretes that have in their composition additives.

scholarly journals Assessing physical and mechanical properties of enclosing rock in the course of Malmyzhskoe gold-copper-porphyry deposit development

2021 ◽  
Vol 1 (3) ◽  
pp. 48-59
Author(s):  
Denis I. Tsoi
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Local Area ◽  
Structural Features ◽  
Strength Properties ◽  
Petrographic Analysis ◽  
Porphyry Deposit ◽  
Copper Porphyry ◽  
Host Rocks ◽  
Enclosing Rocks

Introduction. This work presents the results of complex technological and mineralogical studies. It has been discovered that some natural rocks are characterized by physical and mechanical properties variability 58 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 3. 2021 ISSN 0536-1028 even within a local area. It must be taken into account when assessing enclosing rocks utilization options. The results of Malmyzhskoye rock physical and mechanical properties study at the stage of geological exploration are considered. Research aim is to carry out integrated technological and mineralogical research and laboratory tests on rock physical and mechanical properties to assess the feasibility of using hard enclosing rock for construction. Research methodology. The geological and structural features of the field were established by comparative analysis of geological sections and maps, structural documentation of the core. In laboratory conditions, the physical and mechanical properties of the host rocks that make up the gold-copper-porphyry deposit were established. Results. After studying the mineral (chemical) composition and physical and mechanical properties of rocks, it was possible to obtain the dependence of the strength index on the structure, as well as on the content of dark-colored minerals and plagioclases. At the same time, there are no significant correlations between strength and density within the same rock type. Conclusions. The analysis shows that rocks with the same mineral composition and equal values of the true density, but with different texture and structure, show differences in strength properties. Keywords: Malmyzhskoe deposit; breakability; physical and mechanical properties; rocks; petrographic analysis; density; strength.

scholarly journals Changes in physical and mechanical properties of soils due to anthropogenic impact on the territory of Chita

2021 ◽  
Vol 34 (04) ◽  
pp. 1499-1514
Author(s):  
Danil D. Shesternev
Keyword(s):  
Mechanical Properties ◽  
Anthropogenic Impact ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Deformation Characteristics ◽  
Laboratory Studies ◽  
Freezing And Thawing ◽  
Construction Sites ◽  
Engineering Structures ◽  
Geological Conditions

When constructing buildings and engineering structures it is necessary to make a pit for the foundation construction. Excavation works, construction of buildings and engineering structures change the deformation-strength properties of soils, which lie under the foundations. To study the changes in engineering-geological conditions during 2016-2018, on one of the construction sites in Chita (Russia), a well was made to take a soil sample and laboratory studies on physical and mechanical properties of soils were performed. As a result of the studies, it was established that the deterioration of the soils’ deformation characteristics under the foundations increased by 2.5 times, from 20 MPa to 8 MPa. The strength characteristics changed almost by 2 times. The soil’s specific cohesion changed from 31 MPa to 16 MPa due to freezing and thawing of the soil on the excavation face of the pit with its subsequent soaking. It is necessary to carry out additional activities to strengthen and stabilize the foundations.

Analysis of the stress-strain state of copper M0B under different schemes of equal channel angular pressing and its effect on the structure and physical and mechanical properties

2019 ◽  
pp. 47-53
Author(s):  
L. F. Sennikova ◽  
G. K. Volkova ◽  
V. M. Tkachenko
Keyword(s):  
Equal Channel Angular Pressing ◽  
Strain State ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Stress Strain ◽  
Loading Pattern ◽  
Stress Strain State ◽  
Angular Pressing ◽  
Fine Copper ◽  
Copper Structure

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.

scholarly journals Properties and Structure of Concretes Doped with Production Waste of Thermoplastic Elastomers from the Production of Car Floor Mats

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 872
Author(s):  
Malgorzata Ulewicz ◽  
Alina Pietrzak
Keyword(s):  
Tensile Strength ◽  
Production Process ◽  
Compression Strength ◽  
Physical And Mechanical Properties ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Production Waste ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Average Decrease

This article presents physical and mechanical properties of concrete composites that include waste thermoplastic elastomer (TPE) from the production process of car floor mats. Waste elastomer (2–8 mm fraction) was used as a substitute for fine aggregate in quantities of 2.5, 5.0, 7.5, and 10% of the cement weight. For all series of concrete, the following tests were carried out: compression strength, bending tensile strength, splitting tensile strength, absorbability, density, resistance to water penetration under pressure, frost resistance, and abrasion resistance, according to applicable standards. Moreover, SEM/EDS analysis was carried out on the surface microstructure of synthesized concrete composites. It was proven that the use of production waste from the production process of car floor mats in the quantity of 2.5% does not influence the change of the concrete microstructure and it does not result in the decrease of the mechanical parameters of concrete modified with waste. All concrete modified with the addition of waste meet standards requirements after carrying out 15 cycles of freezing and thawing, and the average decrease in compression strength did not exceed 20%. Adding waste in the quantity of 2.5% allows for limiting the use of aggregate by about 5%, which is beneficial for the natural environment.

scholarly journals RESEARCH OF PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-FIBER MATERIALS

2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina
Keyword(s):  
Mechanical Properties ◽  
Wood Fiber ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Production Method ◽  
Strength Properties ◽  
Grinding Process ◽  
Technological Parameters ◽  
Fiber Materials ◽  
Traditional Construction

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.

scholarly journals Research of the properties of rubber-cord composites in the presence of new adhesion promoters

2020 ◽  
Vol 82 (3) ◽  
pp. 221-226
Author(s):  
O. V. Karmanova ◽  
S. G. Tikhomirov ◽  
E. V. Lintsova ◽  
L. V. Popova
Keyword(s):  
Elevated Temperatures ◽  
Tensile Elongation ◽  
Physical And Mechanical Properties ◽  
Cobalt Content ◽  
Strength Properties ◽  
Adhesion Promoters ◽  
Serial Sample ◽  
Rubber Compounds ◽  
The Cost ◽  
Processing Properties

Studies of experimental adhesion modifiers based on a mixture of fatty acids from the production of light vegetable oils. The properties of rubber compounds and their vulcanizates obtained using experimental adhesion promoters KK with cobalt content from 7.5 to 16.5% are investigated. The plastic-elastic and vulcanization properties of the properties of breaker rubber compounds based on polyisoprene, the physical and mechanical properties of breaker rubbers and the bond strength in the “rubber-brass-plated steel cord system” were studied. When testing belt rubbers containing experienced adhesion promoters or an imported analog of Manobond 680C, the following features were revealed. The plasticity of the prototypes was in the range of 0.2-0.4. This indicates satisfactory processing properties. The Mooney viscosity of the prototypes was lower than that of the production sample. The use of experienced adhesion promoters instead of the analogue (Manobond 680C) increases the resistance to scorching. On the basis of the analysis of elastic-strength properties, it was found that in terms of the conditional tensile strength, the prototypes were inferior to the serial ones. However, rubbers containing the KK-12, KK-13.5, KK-15 promoters met the control standards. The tensile elongation at break of the experimental rubbers is higher than that of the serial sample. This may indicate the formation of a more uniform cure network in the presence of the test products. When testing rubber-metal-hard composites, it was noted that, under normal conditions, the experienced adhesion promoters have advantages over Manobond 680C. However, at elevated temperatures, under conditions of salt and steam-air aging, they are slightly inferior to Manobond 680C. It has been established that the experimental adhesion promoters provide the required set of technical properties of belt rubbers with a CO2 + content of 12–16.5% wt. Thus, it is possible to recommend the adhesion promoters KK 12, KK-13.5, KK 15 for practical use in the composition of belt rubber compounds. This will allow replacing a foreign-made product and reducing the cost of production.

Ceramic Composition Material with Mullite Crystals Obtained from the Clayy Raw Material of Yakutia

2020 ◽  
Vol 992 ◽  
pp. 253-258
Author(s):  
M.P. Lebedev ◽  
V.N. Tagrov ◽  
E.S. Lukin
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
Practical Interest ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Strength Properties ◽  
Raw Material ◽  
Composition Material ◽  
Material Base ◽  
Wide Range

The article deals with the manufacture of modern structural ceramic materials from clay and loam deposits of the Republic of Sakha (Yakutia). The importance and relevance of the development of the production of building materials from local raw materials is emphasized, since this will certainly affect the effectiveness of the construction complex as a whole. The successful development of the construction complex is capable of not only stimulating growth in all sectors of the economy, but also contributes to solving the most pressing social problems. Today, Yakutia has huge reserves of mineral raw materials for the production of a wide range of building materials and products. Of practical interest are wall materials made from clay soils. Given the features of the region’s raw material base, this work focuses on additional processing of traditional material. Controlling the complex physicochemical and structural-mechanical transformations that occur during heat treatment, a methodology has been developed for creating a composite material that will allow competitive innovative materials with enhanced strength properties to be produced with a reinforcing element with a glassy phase matrix of mullite crystals. The fabricated samples have a wide range of physical and mechanical properties and allow using it as a high-quality structural building ceramics, as well as industrial floor technical tile.

scholarly journals The analysis of influence of polymer admixtures on properties of lightweight concrete

2019 ◽  
Vol 252 ◽  
pp. 08007 ◽  
Author(s):  
Jacek Góra ◽  
Danuta Barnat-Hunek ◽  
Paweł Wlaź ◽  
Monika Garbacz
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Statistical Analysis ◽  
Lightweight Concrete ◽  
Strength Properties ◽  
Freezing And Thawing ◽  
Factors Of Influence ◽  
Freezing And Thawing Cycles ◽  
Acetate Copolymer

The article presents the results of testing physical and strength properties of concrete with the addition of lightweight perlite in the amount of 10 and 20%. The additive was introduced by volume substituting a part of the sand. In addition, the effect of using siloxane admixtures and a vinyl acetate copolymer with different degree of dosing, as well as applied simultaneously, were analysed. The tests were carried out in the field of bulk density and proper density, determination of tightness and porosity, compressive strength and tensile strength after 28 days of maturation. In terms of durability of concrete, absorption and resistance of concretes to the freeze-up effects after 100 freezing and thawing cycles were tested. The results of the study were subjected to statistical analysis using the analysis of variance. The analysed factors of influence were the amount of perlite addition, as well as the type and amount of the added admixture

Influence of Physical Properties of B4C Powder on the Strength Properties of the Ceramics Manufactured by SPS Sintering

2015 ◽  
Vol 1085 ◽  
pp. 312-315
Author(s):  
Oleg L. Khasanov ◽  
Edgar S. Dvilis ◽  
Zulfa G. Bikbaeva ◽  
Valentina V. Polisadova ◽  
Alexey O. Khasanov ◽  
...  
Keyword(s):  
Physical Properties ◽  
Boron Carbide ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Strength Properties ◽  
Carbide Powder ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Determining Factor ◽  
Sps Sintering

Ceramics samples in the form of a parallelepiped with high strength characteristics have been made. For the manufacture of the ceramics samples a powder mixture from submicron В4С powder with additives (1 wt%, 5 wt%, 10 wt%) of boron carbide nanopowder was used. The physical properties of the powder mixtures and strength properties of sintered ceramics have been studied. It was shown that the use of submicron fractions of the boron carbide powder together with nanoadditives is a determining factor in the formation of dense fine-grained structure providing improved physical and mechanical properties of the ceramics.

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