Activity Improvement of Sticky Portland Cements by Methods of Mechanical Activation

2019 ◽  
Vol 945 ◽  
pp. 3-8 ◽  
Author(s):  
A.V. Andreeva ◽  
O.N. Burenina ◽  
M.E. Savvinova
Keyword(s):  
Mechanical Activation ◽  
Ball Mill ◽  
Granulometric Composition ◽  
Mechanical Characteristics ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Fine Grained ◽  
Wide Range ◽  
Grinding Machines ◽  
Physical And Mechanical Characteristics

The article presents experimental data on the improvement of physical and mechanical properties and structure of fine-grained concrete by mechanical activation of sticky cement in various apparatuses. It is established that the use of mechanoactivation technologies allows controlling the surface characteristics of cement in a wide range, its granulometric composition, as well as the physical and mechanical characteristics of concrete products. It is revealed that the efficiency of grinding machines that realize various mechanisms of disperse action is not the same. The highest indexes belong to the concrete containing cement, which is mechanically activated on the planetary ball mill AGO-2.

Effect of MgO•Sb2O5 on Fire Resistance and Physical and Mechanical Properties of Cable PVC-Plasticate

2021 ◽  
Vol 899 ◽  
pp. 557-562
Author(s):  
Timur A. Borukaev ◽  
Luiza I. Kitieva ◽  
Abubekir Kh. Shaov ◽  
A.A. Kyarov
Keyword(s):  
Mechanical Properties ◽  
Fire Resistance ◽  
Mechanical Characteristics ◽  
Negative Impact ◽  
Physical And Mechanical Properties ◽  
Antimony Oxide ◽  
Magnesium Carbonate ◽  
Physical And Mechanical Characteristics

Based on magnesium carbonate and antimony oxide (V), MgO•Sb2O5 was obtained. In the formulation of fire-resistant cable PVC-plasticate, antimony (III) oxide was replaced by MgO•Sb2O5 and the fire resistance and physical and mechanical properties of the resulting compound were investigated. It is shown that the replacement of antimony (III) oxide in the composition of PVC cable compound MgO•Sb2O5 leads to the production of a compound that is not inferior in its characteristics to the original plastic compound. In particular, the fire resistance of cable PVC-plasticate, standard industrial formulation and with the obtained MgO•Sb2O5, is practically the same (OI=32%). It has been established that the physical and mechanical characteristics of the cable compound, when replacing antimony oxide (III) with MgO•Sb2O5 in the formulation, remain at the level of the original compound, while MgO×Sb2O5 will have a less negative impact on the environment.

Influence of the Mechanical Activation of Fly Ash on Strength of Ground Concrete Based on Waste Production

2021 ◽  
Vol 25 (11) ◽  
pp. 36-41
Author(s):  
D.V. Bespolitov ◽  
N.A. Konovalova ◽  
O.N. Dabizha ◽  
P.P. Pankov ◽  
E.A. Rush
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Mechanical Activation ◽  
Equilibrium Condition ◽  
Mechanical Characteristics ◽  
Road Construction ◽  
Waste Production ◽  
Direct Use ◽  
Silicon Oxygen ◽  
Physical And Mechanical Characteristics

The possibility of utilization of inactive fly ash in road concrete compositions by bringing of ash into a non-equilibrium condition with increased reactivity by mechanical activation in a vibration eraser is investigated. It was revealed that the optimal content of binder and fly ash in samples of soil concrete was 8 and 10 wt. %, respectively. It is shown that, due to mechanical activation, the specific surface area of fly ash increases by 2 times, dehydration and carbonization occur and silicon is replaced by aluminum in silicon-oxygen tetrahedra. It has been established that an increase of the content of crystalline carbonate phases is the reason for an increase in the strength of ground concrete. It is determined that the introduction of mechanoactivated fly ash into the composition of soil concretes contributes to increasing their physical and mechanical characteristics to the maximum strength grade M100. This indicates the competitiveness of ground concrete and the possibility of direct use of inactive fly ash in road construction.

Study of the Physical and Mechanical Characteristics of the Ice Cover

2019 ◽  
Vol 974 ◽  
pp. 482-487
Author(s):  
A.S. Vasilyev ◽  
V.L. Zemlyak ◽  
V.M. Kozin
Keyword(s):  
Mechanical Characteristics ◽  
Bending Strength ◽  
Winter Season ◽  
Physical And Mechanical Properties ◽  
Ice Cover ◽  
The Arctic ◽  
Structural Failure ◽  
Extreme North ◽  
Far Eastern ◽  
Physical And Mechanical Characteristics

The construction of crossing ferry landings across the Arctic Shelf and the regions located in the Extreme North or Far North, as well as the Siberian and Far Eastern rivers during the winter season is a difficult task of immediate concern. Nevertheless, it is necessary to learn the ice mechanical characteristics in order to examine the bearing capacity of the ice cover at the crossing ferry landings aimed at their establishment and strengthening. The purpose of the paper is to observe the physical and mechanical features of the ice cover by means of doing simulated experiments and verifying their validity using a computational model. The research performed the studies on Young’s modulus of ice definition and bending strength. Ice beam samples were used in the simulated experiments. Their physical and mechanical properties were put to the tests carried out with a special loading device. There was a structural failure of ice beam samples influenced by pure bending. The authors performed numerical computations on the ground of the data obtained by ANSYS software. The calculations resulted in determining condition of the stress-strain state of the samples at any time of loading up to their complete breaking-up. The efficiency of the algorithm is proved by comparing numerical calculations to simulated experimental data.

On the influence of the shaped charge liner manufacture technology on the high-speed element characteristics

2020 ◽  
Author(s):  
V.I. Kolpakov ◽  
N.A. Kudyukov
Keyword(s):  
High Speed ◽  
Mechanical Characteristics ◽  
Physical And Mechanical Properties ◽  
Shaped Charge ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Liner Material ◽  
Metal Spinning ◽  
Cold Stamping ◽  
Physical And Mechanical Characteristics

The paper introduces the results of numerical simulation of the functioning of shaped charges, whose liners are made of different materials. As a result of their functioning, these charges form high-speed elements. Typically, liners for such charges are produced by the cold stamping technology. An alternative method for producing the liners is metal spinning. Moreover, a spin formed liner is expected to have higher physical and mechanical properties compared to a stamped liner made of the same material and having the same geometrical parameters. To reveal the patterns of molding high-speed elements from stamped and spin formed liners, the action of shaped charges comprised of steel or copper segmental liners of small bending, was simulated numerically using the apparatus of continuum mechanics. The influence of the liner manufacture method was taken into account by varying the values of the physical and mechanical characteristics of the liner material. The design parameters of the simulated charge, with the exception of the liner bending, during the calculation study remained unchanged and corresponded to the parameters of the currently used samples. Following the numerical experiments results, the study shows that the elements molded from spin formed liners are less likely to become fractured while being formed and are also more integral (continuous) in comparison to the elements molded from stamped shaped charge liners.

Physical and mechanical characteristics of cement mortars and concretes with addition of clinoptilolite from Beli Plast deposit (Bulgaria), silica fume and fly ash

Clay Minerals ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 213-223 ◽  
Author(s):  
V. Lilkov ◽  
I. Rostovsky ◽  
O. Petrov
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Mechanical Characteristics ◽  
Physical And Mechanical Properties ◽  
Specific Pore Volume ◽  
Cement Mortars ◽  
Physical And Mechanical Characteristics

AbstractCement mortars and concretes incorporating clinoptilolite, silica fume and fly ash were investigated for changes in their physical and mechanical properties. It was found that additions of 10% clinoptilolite and 10% Pozzolite (1:1 mixture of silica fume and fly ash) were optimal for improvement of the quality of the hardened products, giving 8% and 13% increases in flexural and compressive strength respectively. The specific pore volume of the mortars incorporating zeolite decreased between the 28th and 180th day to levels below the values for the control composition due to the fact that clinoptilolite exhibits its pozzolanic activity later in the hydration. In these later stages, pores with radii below 500 nm increased at the expense of larger pores. The change in the pore-size distribution between the first and sixth months of hydration occurs mostly in the mortars with added zeolite.

scholarly journals Waterproofing material for protection of underground structures

2019 ◽  
Vol 97 ◽  
pp. 02008
Author(s):  
Olga Lyapidevskaya
Keyword(s):  
Crack Resistance ◽  
Mechanical Characteristics ◽  
Physical And Mechanical Properties ◽  
Ethylene Vinyl Acetate ◽  
Hard Coatings ◽  
Optimal Composition ◽  
Underground Structures ◽  
High Elasticity ◽  
Main Disadvantage ◽  
Physical And Mechanical Characteristics

The article deals with the problem of increasing the durability of underground and buried buildings. One of the methods of solving this problem is ensuring the reliable protection of underground structures from the effects of water of different origin. Among the existing waterproofing coatings, mineral-based compositions are the most effective. However, the main disadvantage of such systems is the low crack resistance of hard coatings, which limits their applicability. We have made an attempt to develop a cement-based waterproofing material that would have high elasticity, strength, crack resistance and adhesion to a concrete base. We have conducted studies to justify the possibility of obtaining an effective waterproofing material by including microsilica and ethylene vinyl acetate in the mix. The optimal composition of the material was worked out. On the basis of the experimental data, the main physical and mechanical properties of the material were established. Based on the obtained results, it was found that the resulting material had high physical and mechanical characteristics and could be recommended for the protection of concrete structures used in underground construction.

scholarly journals Error estimation of the physical and mechanical characteristics measurements by indentation

2018 ◽  
Vol 9 (3) ◽  
pp. 263-271
Author(s):  
A. P. Kren ◽  
O. V. Matsulevich ◽  
M. N. Delendik
Keyword(s):  
Measurement Error ◽  
Error Estimation ◽  
Evaluation System ◽  
Mechanical Characteristics ◽  
Physical And Mechanical Properties ◽  
Strain Hardening Exponent ◽  
Indirect Measurements ◽  
Static Indentation ◽  
Indentation Methods ◽  
Physical And Mechanical Characteristics

The active application in the practice of testing the indentation methods, in particular to measure the physical and mechanical properties of metals, polymers, biological technologies demands to development techniques for the measurement error estimation. At the same time existing traditional measurement error evaluation system, based on the using of the reference blocks, is not always suitable for use in testing and research laboratories. The aim of this work was development the technique for estimating the indirect measurements error of materials physical and mechanical characteristics that can be applied in practice and based on the existing standards. Checking of the proposed approach using the experimental values of the hardness and elastic modulus obtained during static indentation for various metals.It is shown that since the initial information about the material is an indentation curve representing the dependence of the load versus penetration depth of the indenter into the material tested, then it is better to confirm the metrological characteristics of the indentation measuring devices using the applied force and achieved displacement, but to estimate the accuracy of determining the properties through the error of indirect measurements. The equations for calculating the hardness and modulus of elasticity are derived. It allows to determine the component value most influencing the error magnitude. The calculation of error on the base of the value of boundary of a random and non-exclusive systematic error was carrying out.The advantage of the developed technique is the fact that the measurement of the physical and mechanical characteristics is based on the experimental data and does not require the creation of the additional metrological assurance. The proposed approach seems appropriate to extend for the determination of the measurement error of other characteristics: the yield point, the strain hardening exponent, creep, relaxation, determined by the indentation methods.

scholarly journals Basic physical and mechanical characteristics of ice based on the results of the expedition “Transarktika-2019”

2020 ◽  
Vol 66 (3) ◽  
pp. 293-320
Author(s):  
S. M. Kovalev ◽  
V. A. Borodkin ◽  
N. V. Kolabutin ◽  
A. A. Nubom ◽  
Ev. V. Shimanchuk ◽  
...  
Keyword(s):  
Sea Ice ◽  
Uniaxial Compression ◽  
Mechanical Characteristics ◽  
Lower Boundary ◽  
Physical And Mechanical Properties ◽  
Average Density ◽  
Current Season ◽  
Ice Surface ◽  
Second Year ◽  
Physical And Mechanical Characteristics

On the “Transarktika-2019” expedition, works were carried out for determining the physical and mechanical characteristics of frost field of the first-year sea ice and the field of second-year ice. The thickness of the ice cover was determined by contact and non-contact methods, the temperature, salinity and density of ice, the strength of the samples at central bending and uniaxial compression, as well as the local (borehole) strength of ice were measured. Studies have shown that most of the field is an ice formation formed in the process of dynamic metamorphism. At the beginning of the expedition, an ice floe passed through a section of warm surface waters. This led to the disappearance of the openwork layer on the lower boundary of the ice and stopping the growth of ice from below. During the observation period, the average temperature and salinity of the deformed ice increased, while the average density decreased. The values of mechanical characteristics decreased with increasing temperature and brine volume. The average borehole strength were close to the values obtained by the quadratic approximation for ice in the area of the Ice Station “Cape of Baranov”. The physical and mechanical properties of the level ice are generally similar to the properties of ice, composed mainly of fibrous structures. The ratios between the borehole strength and the strength under uniaxial compression of ice samples drilled parallel to the ice surface were 4.5 and 4.7, which corresponds to the literature data. The thickness of the second-year sea ice at the place of work was 166 — 169 cm, the snow height was 27 cm, the raft of the ice surface above the water surface was 15 cm. The average ice temperature was –4.0 °C. Second-year ice can be divided into three parts that differ in their physical properties. The upper part (0 — 10 cm) was formed in the autumn. The second part (10 — 85 cm) is ice that has undergone seasonal thermometamorphic changes. The lower part was formed during the natural growth of ice from below at the current season.

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