scholarly journals SYNTHESIS OF STRUCTURES OF CELLULAR-CONCRETE COMPOSITES WITH NANOSIZED COMPONENTS

Vestnik MGSU ◽  
2017 ◽  
pp. 733-740
Author(s):  
Valentina Anatol'yevna Solonina ◽  
Galina Alexandrovna Zimakova ◽  
Dmitriy Sergeevich Baianov ◽  
Pavel Valer'evich Sharko ◽  
Marina Petrovna Zelig
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Pore Structure ◽  
Physical And Mechanical Properties ◽  
Structure And Properties ◽  
Integrated Research ◽  
High Calcium ◽  
Nanopore Structure ◽  
Matrix Stone ◽  
Cellular Concrete

The article reveals the results of one of the stages of the integrated research studying the influence of compounds and disperse characteristics of silica-containing materials on structure formation and qualities of cellular concrete. It has been indicated that the improvement of physical and mechanical properties of cellular concrete can be achieved through creating the best possible pore structure of the concrete and the structure of interporous frame as well as intensification of hydration and crystallization processes under hydrothermal treatment and, as a result, the increase in number and perfecting morphology of hydrated phases. Up-to-date knowledge about the structure and properties of cellular concrete shows potential capacities to enlarge strength characteristics through forming a nanopore structure of a matrix stone, the effective usage of power potential of multicomponent binding including Portland cement, high-calcium lime, activate silica components with grains of submicron and nanometer range.

Impact of Superplasticizing Agents on Physical and Mechanical Properties of Cellular Concrete

2019 ◽  
Vol 974 ◽  
pp. 181-186
Author(s):  
V.A. Perfilov ◽  
V.V. Gabova ◽  
Inessa A. Tomareva
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Pore Space ◽  
Experimental Studies ◽  
Basalt Fiber ◽  
Physical And Mechanical Properties ◽  
Foam Concrete ◽  
Cellular Concrete

The effect of superplasticizing, foam agents, various fiber aggregates on the physical and mechanical properties of cellular concrete has been studied. The article covers the results of experimental studies conducted to determine the effect of foam agents PO-6 and PB-2000, as well as polymeric and basalt fiber on the pore structure of foam concrete. The dependence between the change in density and strength of cellular concrete and the structure of its pore space has been determined.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

scholarly journals Characteristics of Lightweight Cellular Concrete and Effects on Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2678 ◽  
Author(s):  
Wei Yu ◽  
Xu Liang ◽  
Frank Mi-Way Ni ◽  
Abimbola Grace Oyeyi ◽  
Susan Tighe
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
High Definition ◽  
Pore Characteristics ◽  
Software Applications ◽  
Solid Part ◽  
Electron Microscopes ◽  
Lab Test ◽  
Scanning Electron Microscopes ◽  
Cellular Concrete

This study investigated the pore structure and its effects on mechanical properties of lightweight cellular concrete (LCC) in order to understand more and detailed characteristics of such structure. As part of investigation, environment scanning electron microscopes (ESEM) and industrial high-definition (HD) macro photography camera were separately used to capture and compare images of specimens. Physical properties of the pore structure, including pore area, size, perimeter, fit ellipse, and shape descriptors, were studied based on the image processing technology and software applications. Specimens with three different densities (400, 475, and 600 kg/m3) were prepared in the laboratory. Firstly, the effects of density on the characteristics of pore structure were investigated; furthermore, mechanical properties (compressive strength, modulus of elasticity and Poisson’s ratio, flexural strength and splitting tensile strength of LCC) were tested. The relationships among pore characteristics, density, and mechanical properties were analyzed. Based on the results obtained from the lab test—comparisons made between specimens with high-densities and those with low-densities—it was found significant variability in bubble size, thickness, and irregularity of pores. Furthermore, the increase of density is accompanied by better mechanical properties, and the main influencing factors are the thickness of the solid part and the shape of the bubble. The thicker of solid part and more regular pores of LCC has, the better mechanical properties are.

Basic Physical and Mechanical Properties of Composites Based on Three Different Cements

2016 ◽  
Vol 677 ◽  
pp. 186-190 ◽  
Author(s):  
Monika Čáchová ◽  
Eva Vejmelková ◽  
Kateřina Šestáková ◽  
Pavel Reiterman ◽  
Martin Keppert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Open Porosity ◽  
Mercury Porosimetry ◽  
Physical And Mechanical Properties ◽  
Mineralogical Composition ◽  
Physical Parameters ◽  
Vacuum Saturation ◽  
Saturation Method ◽  
Properties Of Composites

This article is focused on cement based composites. Two cements differing in mineralogical composition are utilised as main binder in composites mixtures. Results of measured physical parameters of studied materials are presented. For the sake of comparison, a reference material with Portland cement was also prepared. Basic physical properties (measured by water vacuum saturation method and by helium pycnometry), characterizations of pore system (determined by mercury porosimetry) and mechanical properties are the matter of this study. Composites show various open porosity; the results of open porosity of materials containing special cements show higher values, in comparison with composite based on Portland cement. This fact of course influences other material characteristics - mainly mechanical properties.

scholarly journals Influence of nanocellulose on the hydration process of Portland cement and concrete properties

2020 ◽  
Vol 17 (5) ◽  
pp. 155-160
Author(s):  
V. I. Khirkhasova ◽  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Physical And Mechanical Properties ◽  
Cement Composite ◽  
High Density ◽  
Strength Characteristics ◽  
New Method ◽  
Concrete Properties ◽  
Hardening Process ◽  
Study Results

The paper deals with modification of cement composite and concrete with nanocellulose in low and high density. The author presents the study results of the influence of nanocellulose on the cement composite hardening process, as well as the physical and mechanical properties of heavy concrete. The influence of the used additive on the rheological and strength characteristics of concrete is revealed. A new method is proposed to improve the material performance.

scholarly journals MICROESTRUTURA E PROPRIEDADES FÍSICAS E MECÂNICAS DE CIMENTO PORTLAND TIPO II ÁLCALI-ATIVADO / MICROSTRUCTURE AND PHYSICAL AND MECHANICAL PROPERTIES OF ALKALI-ACTIVATED TYPE II PORTLAND CEMENT

2020 ◽  
Vol 6 (11) ◽  
pp. 84929-84951
Author(s):  
Luccas Mansur Feuchard ◽  
Cléo Márcio de Araújo Santana ◽  
Eliane Fernandes Côrtes Pires ◽  
Fernando Luiz Barbuda de Abreu ◽  
Elie Chahdan Mounzer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Physical And Mechanical Properties ◽  
Type Ii ◽  
Alkali Activated

scholarly journals Assessment of Physical and Mechanical Properties of Concrete Produced from Various Portland Cement Brands

2019 ◽  
Vol 09 (04) ◽  
pp. 327-337
Author(s):  
Asal Soltani ◽  
Salim Khoso ◽  
Manthar Ali Keerio ◽  
Antonio Formisano
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Physical And Mechanical Properties

Differences in petrophysical and mechanical properties between low- and middle-rank coal subjected to liquid nitrogen cooling in coalbed methane mining

2021 ◽  
pp. 1-10
Author(s):  
Menglin Du ◽  
Feng Gao ◽  
Chengzheng Cai ◽  
Shanjie Su ◽  
Zekai Wang
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Liquid Nitrogen ◽  
Coalbed Methane ◽  
Bituminous Coal ◽  
Thermal Damage ◽  
Physical And Mechanical Properties ◽  
Damage Degree ◽  
Lignite Coal ◽  
The Difference

Abstract Exploring the damage differences between different coal rank coal reservoirs subjected to liquid nitrogen (LN2) cooling is of great significance to the rational development and efficient utilization of coalbed methane. For this purpose, the mechanical properties, acoustic emission (AE) characteristics and energy evolution law of lignite and bituminous coal subjected to LN2 cooling were investigated based on the Brazilian splitting tests. Then, pore structure changes were analyzed to reveal the difference in the microscopic damage between lignite and bituminous coal after LN2 cooling. The results showed that compared with bituminous coal, the pore structure of lignite coal changed more obviously, which was manifested as follows: significant increases in porosity, pore diameters, and pore area; a larger transformation from micropores and transition pores to mesopores and macropores. After LN2 cooling, the thermal damage inside lignite and bituminous coal was 0.412 and 0.069, respectively. The thermal damage reduced the cohesive force between mineral particles, leading to the deterioration of the macroscopic physical and mechanical properties. Simultaneously, denser AE ringing counts and larger accumulated ringing counts were observed after LN2 cooling. Moreover, the random distribution of thermal damage enhanced the randomness of the macrocrack propagation direction, resulting in an increase in the crack path tortuosity. With more initial defects inside coal, a more obvious thermal damage degree and wider damage distribution will be induced by LN2 cooling, leading to more complicated crack formation paths and a higher fragmentation degree, such as that of lignite coal.

Contribution of the hybrid component to the structure and properties of ceramics based on metastable phases Al2O3

2021 ◽  
pp. 127-136
Author(s):  
A. V. Maletsky ◽  
T. E. Konstantinova ◽  
D. R. Belichko ◽  
G. K. Volkova ◽  
V. V. Burkhovetsky
Keyword(s):  
Mechanical Properties ◽  
Yttrium Aluminum Garnet ◽  
Metastable Phase ◽  
Physical And Mechanical Properties ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Mutual Inhibition ◽  
X Ray ◽  
Tetragonal Lattice ◽  
Yttrium Aluminum

The paper presents results of the study of the effect of doping with yttrium oxide on ceramics of the composition (γ + θ) Al2O3 + nY2O3 (n = 0, 1, 2, 3 wt%), sintered at 1550°C for 2 h, from powders of the specified composition annealed at temperatures of 500 , 800, 1000°С. X-ray diffraction analysis established the formation in ceramics of yttrium aluminum garnet Y3Al5O12 (YAG) and a metastable phase of the same composition with a tetragonal lattice type in powders at temperatures above 1200°C. The effect of YAG on the physical and mechanical properties was established: high properties were demonstrated by ceramics of the composition α-Al2O3 + 2wt% Y2O3, obtained from a powder annealed at 1000°C. In addition, high physical and mechanical properties were observed in ceramics of the composition α-Al2O3 + 0wt% Y2O3, obtained from a powder annealed at 800°C. The effect of the so-called “mutual protection against crystallization” was discovered, which consists in the mutual inhibition of crystallization processes in powders of the Al2O3 – Y2O3 system.

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