Effective Fine-Grained Concrete with High-Dispersed Additive Based on the Natural Mineral Wollastonite

2019 ◽  
Vol 945 ◽  
pp. 85-90 ◽  
Author(s):  
E.G. Karpikov ◽  
N.P. Lukutsova ◽  
E.A. Bondarenko ◽  
V.V. Klyonov ◽  
A.E. Zajcev
Keyword(s):  
Raw Materials ◽  
Selective Adsorption ◽  
Aggregate Stability ◽  
Rheological Parameters ◽  
Ultrasonic Dispersion ◽  
Natural Mineral ◽  
Fine Grained ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Micro Fillers

Micro-fillers based on natural mineral wollastonite, modifying fine-grained concrete and improving its physical and mechanical characteristics, are developed and studied. The influence of the most common stabilizers on the aggregate stability of wollastonite-based microdispersed systems in the aquatic dispersion environment is considered. The optimal parameters, ensuring the production of micro-fillers in the form of stable suspensions, are developed. The application efficiency of the wollastonite-based filler due to its micro-reinforcing properties is revealed. These properties are specified by the formation of needle-shaped crystals by the ultrasonic dispersion in the aquatic environment, chemically related to cement-containing raw materials and contributing to the active selective adsorption of the binder hydration products. It has a significant influence on the rheological parameters of cement composites, on structure formation, as well as on their strength and deformation properties.

Effective Fine Concrete Modified with a Highly Dispersed Wollastonite-Based Additive

2021 ◽  
Vol 887 ◽  
pp. 422-427
Author(s):  
E.G. Karpikov ◽  
N.P. Lukuttsova ◽  
T.P. Blagoder ◽  
E.A. Bondarenko
Keyword(s):  
Raw Materials ◽  
Particle Diameter ◽  
Solid Particles ◽  
Average Particle ◽  
Ultrasonic Dispersion ◽  
Fine Grained ◽  
Highly Dispersed ◽  
Surface Active ◽  
Portland Slag Cement ◽  
Polycarboxylate Ether

An effective highly dispersed additive based on the wollastonite Miwoll 05-97 with an average particle diameter of 6.5 microns is obtained. A stable effect of interacting the additive components with Portland slag cement CEM II/A–Ш 42.5H is revealed; it results in improving the strength of fine-grained concrete produced with the raw materials mentioned above. It is established that using water suspension of wollastonite solid particles, highly water-reducing/superplasticizing modifier based on the polycarboxylate ether Master Glenium 430, as a stabilizer of the surface-active substance allows producing an additive with an evener distribution of solid particles in the liquid, and with stable functional properties. A highly dispersed wollastonite-based additive, obtained by ultrasonic dispersion for 10 minutes in the bath-type activator at the frequency of 35 kHz in the aquatic environment with a suspension stabilizer, enables producing the wollastonite-modified fine concrete with a compressive strength of more than 50 MPa, with the 10% additive being 2 times higher than that of the control.

The Residual Stress in Thawing Soils

1973 ◽  
Vol 10 (4) ◽  
pp. 571-580 ◽  
Author(s):  
J. F. Nixon ◽  
N. R. Morgenstern
Keyword(s):  
Residual Stress ◽  
Effective Stress ◽  
Simple Procedure ◽  
Frozen Soil ◽  
Fine Grained ◽  
Deformation Properties ◽  
Fine Grained Soil ◽  
Soil Skeleton ◽  
Strength And Deformation ◽  
Undrained Strength

If a fine grained soil is thawed under undrained conditions, in general an effective stress exists in the soil skeleton. This effective stress is termed the residual stress. In ice-rich soil the residual stress may be zero, but various combinations of stress and thermal histories can result in significant residual stresses being generated upon thawing.A simple procedure for measuring the residual stress is described and the method is employed to obtain values for the residual stress in natural and reconstituted samples of frozen soil. The residual stress is found to be dependent on the void ratio in the thawed undrained condition. A profile of the residual stress with depth is given for the natural permafrost samples that have been tested.Some implications of the residual stress in practice are discussed, with particular emphasis on the undrained strength and deformation properties of thawed permafrost.

scholarly journals EFFECT OF DOSAGE OF REDISPUTABLE POWDERS AND THE TYPE OF LOW-MODULAR INCLUSIONS ON THE PROPERTIES OF FINE-AGGREGATE CONCRETE

2019 ◽  
Vol 46 (2) ◽  
pp. 167-175 ◽  
Author(s):  
A. V. Dolgova ◽  
G. V. Nesvetaev
Keyword(s):  
Fine Aggregate ◽  
Fine Grained ◽  
Deformation Properties ◽  
Low Modulus ◽  
Strength And Deformation ◽  
Properties Of Materials ◽  
Materials Used ◽  
Entrained Air ◽  
Polymer Powders

Objectives Reliability and durability of structures using materials with various properties (plaster coatings, cement glue, new concrete during repair and restoration of structures, etc.) largely depends on the adhesion of the layers and the deformation properties of the coatings. To obtain the required properties of materials used for coatings, modifiers based on polymers and low-modulus inclusions are introduced into the composition of new concretes, for example, entrained air. The aim of the work is to identify some patterns of change in the properties of concrete with the joint introduction of these modifiers.Method Experimental determination of the tensile strength in bending, compression, E-modulus, adhesion to the concrete base by standard methods.Result The influence of separate and joint introduction of dispersible polymer powders and various low-modulus inclusions into the composition of fine-grained concrete has been established.Conclusion The joint introduction to the composition of fine-grained concrete of various low-modulus inclusions and redispersible polymer powders provides a reduction in the stress level during forced deformations due to the different effects additives on the strength and deformation properties and contributes to increased adhesion to the concrete. 

scholarly journals The Influence of Specimen Geometry and Loading Conditions on the Mechanical Properties of Porous Brittle Media

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7144
Author(s):  
Anatoly M. Bragov ◽  
Andrey K. Lomunov ◽  
Leonid A. Igumnov ◽  
Aleksandr A. Belov ◽  
Victor A. Eremeyev
Keyword(s):  
Porous Media ◽  
Dynamic Stress ◽  
Uniaxial Stress ◽  
Dynamic Tests ◽  
Zirconia Ceramics ◽  
Specimen Length ◽  
Fine Grained ◽  
Optimal Geometry ◽  
Deformation Properties ◽  
Strength And Deformation

Dynamic tests of fine-grained fired dioxide-zirconia ceramics under compression under uniaxial stress conditions were carried out. The influence of the specimen length on the obtained strength and deformation properties of ceramics is investigated. The thickness of the specimen has a significant impact on the course of the obtained dynamic stress–strain diagrams: short specimens have a much more sloping area of active loading branch. The main contribution to the modulus of the load branch resulting from tests of brittle porous media is made by the geometry of the specimens and the porosity of the material. When choosing the length of specimens for dynamic tests, the optimal geometry of the tested specimens is preferable in accordance with the Davies–Hunter criterion, when the contributions of axial and radial inertia are mutually compensated, and the contribution of the effects of friction in the resulting diagram is minimal. When choosing the geometry of specimens of brittle porous media, the structure of the material should be taken into account so that the size of the specimen (both length and diameter) exceeds the size of the internal fractions of the material by at least five times.

Effective Highly Dispersed Additive for Concretes on the Basis of Natural Mineral Raw Materials

2020 ◽  
Vol 992 ◽  
pp. 168-172
Author(s):  
E.G. Karpikov ◽  
N.P. Lukuttsova ◽  
E.A. Bondarenko
Keyword(s):  
Compressive Strength ◽  
Bending Strength ◽  
Raw Materials ◽  
Chemical Activation ◽  
Raw Material ◽  
Experiment Planning ◽  
Water Medium ◽  
Natural Mineral ◽  
Fine Grained ◽  
Highly Dispersed

The composition of a highly dispersed additive for concrete based on the natural mineral raw material wollastonite is developed. The properties of the modified fine-grained concrete (FGC) are studied. The three-factor experiment planning made it possible to obtain mathematical dependences of the bending and compressive strength after 3 and 28 days of hardening, density, and water-cement ratio of the fine-grained concrete on such factors as the content of anionic surfactant of naphthalene-formaldehyde type in the composition of the raw material wollastonite being an activator of mechanic-chemical processing, the suspension stabilizer of the pre-activated material, and the content of S-3+wollastonite in powder after mechanic-chemical activation in the suspension. The dependence nomograms are built. The optimal strength parameters of the modified fine-grained concrete with the content of a highly dispersed additive of 5% by weight of cement in its composition, and the wollastonite concentration of 3 g/l in the water medium of the suspension stabilizer S-3 are ascertained. The developed highly dispersed additive allows obtaining fine-grained concrete with the bending strength of 3.1 MPa and the compressive strength of 57.8 MPa.

Experimental Research on the Qualitative Characteristics of Iron Ores and Ferrous Waste That Can Be Used in Blast Furnace Mixt Injection Technology

2019 ◽  
Vol 70 (11) ◽  
pp. 3835-3842
Author(s):  
Mihai Dumitru Tudor ◽  
Mircea Hritac ◽  
Nicolae Constantin ◽  
Mihai Butu ◽  
Valeriu Rucai ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Experimental Research ◽  
Raw Materials ◽  
Coal Dust ◽  
Production Costs ◽  
Iron Ores ◽  
Fine Grained ◽  
Experimental Laboratory ◽  
Injection Technology ◽  
Direct Use

Direct use of iron ores in blast furnaces, without prior sintering leads to a reduction in production costs and energy consumption [1,2]. Fine-grained iron ores and iron oxides from ferrous wastes can be used together with coal dust and limestone in mixed injection technology through the furnace tuyeres. In this paper are presented the results of experimental laboratory investigations for establishing the physic-chemical characteristics of fine materials (iron ore, limestone, pulverized coal) susceptible to be used for mixed injection in blast furnace. [1,4]. The results of the experimental research have shown that all the raw materials analyzed can be used for mixt injection in blast furnace.

The mechanical behavior of the Kettle Point oil shale

1986 ◽  
Vol 23 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Maurice B. Dusseault ◽  
Matthias Loftsson ◽  
David Russell
Keyword(s):  
Oil Shale ◽  
Clay Content ◽  
Organic Content ◽  
Point Load ◽  
Brazilian Test ◽  
Point Load Strength ◽  
Triaxial Strength ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Oil Shales

Samples of eastern black shale (Kettle Point oil shales, Ontario) were subjected to extensive mineralogical and geomechanical tests. We prove that the mineralogy, as measured by the ratio of quartz to illite, controls strength and deformation properties, and the organic material plays no significant role. The reason is that increasing clay content dilutes the rigid quartz–quartz grain contacts that are responsible for the high strengths and stiff behavior. Tests of temperature effects on point load strength of another low organic content oil shale confirm that organic matter is not important to mechanical properties in matrix-supported shales. Key words: shale, mineralogy, Brazilian test, triaxial strength, organic content, slake durability, thermogravimetry.

scholarly journals Effect of carbon nanotubes on the properties of pmb and asphalt concrete

Vestnik MGSU ◽  
2015 ◽  
pp. 110-119 ◽  
Author(s):  
Svetlana Yur’evna Shekhovtsova ◽  
Marina Alekseevna Vysotskaya
Keyword(s):  
Asphalt Concrete ◽  
Water Resistance ◽  
Materials Science ◽  
Crosslinking Agent ◽  
Modern World ◽  
Progressive Development ◽  
Concrete Mixtures ◽  
Deformation Properties ◽  
Strength And Deformation ◽  
Modified Binder

In the modern world nanotechnologies are an integral part of successful and progressive development of all the areas of activity. Materials science is not an exception. The authors studied the method of nanomodification and its influence on the performance properties of polymer-modified binder (PMB) and asphalt concrete, produced on their basis. It is established that nanomodified PMB are less susceptible to aging, which is a consequence of the processes of peptization of asphalt-resin complexes (ARC) in the structure of the modified binder and the crosslinking with the polymer matrix. It is revealed that nanotubes (SWCN or MWCN) used as a modifier, act as crosslinking agent and the inhibitor of the aging process in a PMB. The influence of nanomodified PMB on strength and deformation properties of asphalt concrete is investigated. It was found out that the use of modified binder in the asphalt concrete mixtures enhances the water resistance of asphalt concrete, heat resistance and shear-resistance.

scholarly journals AN EFFECTIVE WAY TO RECYCLE 3D PRINTING CONCRETE SCRAP

2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Portland Cement ◽  
Quartz Sand ◽  
Raw Materials ◽  
Electricity Consumption ◽  
Cement Matrix ◽  
Fine Aggregate ◽  
Fine Grained ◽  
Control Samples

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials

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