Fine Grain Concrete on Mixing Water Activated in Cavitation Permanent Magnet-Type Apparatus

2019 ◽  
Vol 816 ◽  
pp. 279-284 ◽  
Author(s):  
Marina A. Akulova ◽  
T.E. Slizneva ◽  
P.B. Razgovorov ◽  
Alla G. Sokolova
Keyword(s):  
Bending Strength ◽  
Magnetic Treatment ◽  
Cement Stone ◽  
Porous Space ◽  
Sodium Thiosulphate ◽  
Freeze Thaw ◽  
Fine Grain ◽  
The Impact ◽  
Mixing Water ◽  
Magnetic Activation

The authors obtained fine grain concrete based on the mortars of additives-electrolytes undergone mechanic magnetic activation and characterized by improved compression and bending strength and enhanced freeze-thaw resistance. There was investigated the impact of mechanic magnetic activation (MMA) on mixing water when adding calcium chloride and sodium thiosulphate as well as on porosity of cement stone and specific features of phase formation in cement stone. It was stated by the authors that MMA facilitates formation of nucleation centers in activated water in the presence of additives-electrolytes, optimization of porous space as well as crystallization of calcium carbonate in the form of aragonite when lowering the content of Portlandite. The mechanism of joined influence of hydrodynamic and magnetic treatment of mixing water has been determined.

scholarly journals THE EFFECT OF COMPLEX MULTI-PURPOSE ADDITIVE ON OPERATING PROPERTIES OF HYDRATED CEMENT AND CONCRETE

2020 ◽  
Vol 22 (5) ◽  
pp. 139-152
Author(s):  
O. V. Dem'yanenko ◽  
A. A. Kulikova ◽  
N. O. Kopanitsa
Keyword(s):  
Materials Science ◽  
Physicochemical Analysis ◽  
Industrial Wastes ◽  
Cement Stone ◽  
Hydrated Cement ◽  
Fine Grain ◽  
Cement And Concrete ◽  
Required Quality ◽  
Mixing Water

The research developments in materials science in the construction field concerning the formulation and production process of fine-grain concrete are aimed at the formation of structure and properties that provide the appropriate performance characteristics. The literature review and experimental data on the concrete treatment made show that the required quality of concrete can be achieved by changing the concrete mixture composition, activation of aggregate and mixing water, introduction of multi-purpose modifying additives, different approaches, etc. The paper presents the development of the effective multi-purpose additive consisting of such industrial wastes as marble-microcalcite, nano silicon dioxide, microsilica, and peat hermally modified at 600 °C. The influence of this additive on hydrated cement and concrete properties is studied herein. It is shown that the introduction of the multi-purpose additive in an amount of 5 % with a decrease in the cement consumption, improves the compressive strength of hydrated cement stone up to 69 %. The chemical composition of new formations of modified hydrated cement is determined by the physicochemical analysis.

scholarly journals Investigations on Flexural and Compressive Strengths of Mortar Dedicated to Clinker Units—Influence of Mixing Water Content and Curing Time

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 347
Author(s):  
Jan Kubica ◽  
Iwona Galman
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Laboratory Tests ◽  
Bending Strength ◽  
Mechanical Parameters ◽  
Curing Time ◽  
The Impact ◽  
Mixing Water

The article presents laboratory tests on the impact of the mixing water content used in the preparation of fresh mortar on the flexural and compressive strength of one of the dry-mix mortars produced by a leading European producer and dedicated to bricklaying with clinker elements. The development of these parameters in relation to curing time was also analyzed. The mortar samples were prepared from a factory-made mortar mix using 4.0 L (the value recommended by the mortar manufacturer), 4.5 L, and 5 L of water per 25 kg bag of ready-made, pre-mixed dry mortar mix. All samples were tested in five series after 5, 9, 14, 21, and 28 days of sample curing. The results of these tests showed that the use of 6 and 18% more mixing water than recommended by the manufacturer (4.5 and 5 L per bag) adversely affected the basic mechanical parameters of the tested mortar. Moreover, it was found that the highest compressive strength values were obtained after 21 days of curing and not after 28 days as usual. It was also found that hardening time and higher than recommended water content adversely affected the bending strength of the mortar.

scholarly journals Effect of mixing water magnetic activation cycle on cement stone structure

2015 ◽  
Vol 71 ◽  
pp. 012013 ◽  
Author(s):  
S A Kugaevskaya ◽  
Yu A Abzaev ◽  
V N Safronov ◽  
Yu S Sarkisov ◽  
N P Gorlenko ◽  
...  
Keyword(s):  
Cement Stone ◽  
Mixing Water ◽  
Activation Cycle ◽  
Magnetic Activation

Obtaining Nanofibers Na-CMC in Mechanomagnetic Activated Water Solution for the Purpose of Reinforcing Concrete Structure

2020 ◽  
Vol 869 ◽  
pp. 107-111
Author(s):  
Marina A. Akulova ◽  
Tatjana E. Slizneva ◽  
Yulia Sokolova ◽  
Alla G. Sokolova
Keyword(s):  
Water Solution ◽  
Cement Stone ◽  
Cement Composites ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Dispersion Phase ◽  
X Ray ◽  
Nanosize Particles ◽  
The Impact ◽  
Mixing Water

The authors have studied the impact of mechanomagnetic activation (MMA) of the solutions NA-CMC, widely used for mixing water-cement paste, on the structure and properties of cement composites. By the method of dynamic light scattering, the appearance of nanosize particles of grouting fluid’s dispersion phase has been proved. On the base of the results of X-ray diffraction analysis, there have been found alterations of cement stone structure; the influence of MMA on the processes of structure formation has been proved; the principal components of cement stone structure have been identified.

Study Of Structure Formation Of Organic-Mineral Compositions With Fibrous Filler By Electron Microscopy Method

2019 ◽  
pp. 41-47
Keyword(s):  
Electron Microscopy ◽  
Structure Formation ◽  
Mineral Composition ◽  
Bending Strength ◽  
Cement Stone ◽  
Hydrated Cement ◽  
Fibrous Filler ◽  
Organic Mineral ◽  
Microscopy Method ◽  
Mineral Compositions

The article presents the study of processes of structure formation of cement stone and products of hardening of organic-mineral compositions with fibrous filler (shavings) by the electronic scanning microscopy method. It is established that the additive-free cement stone at the age of 28 days has a dense and homogeneous structure, consists of calcium hydro-silicates, Portlandite and calcite - newgrowths characteristic for cement systems. Cellulose fibers, which make up the bulk of the substance of shavings, are sufficiently active, which determines the high adhesion of the hydration products of the cement binder to their surface. It is shown that the introduction of shavings into the organo-mineral composition leads to inhibition of cement hydration processes. Organo-mineral compositions with different shavings content (two compositions) were analyzed. The first composition is characterized by a fairly dense structure, the cement stone consists of globular nanoscale nuclei of hydrosilicates, Portlandite and calcite. The second composition has a loose porous structure, cement stone consists of non-hydrated cement grains, newgrowths are represented by calcite and vaterite. The structure of the contact zone "osprey fiber-cement stone" in the organo-mineral composition of the first composition indicates a good adhesion of the filler surface with the phases of hydrated cement. The use of shavings as a fibrous filler (the first composition) increases the tensile and bending strength, as well as the wear resistance of organo-mineral compositions. The data obtained by scanning electron microscopy are confirmed by the results of studying the processes of structure formation of cement stone by quantitative x-ray phase analysis.

Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel

2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Spark Plasma Sintering ◽  
High Speed ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Speed Steel ◽  
Continuous Heating ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

scholarly journals POROSITY PARAMETERS OF CEMENT STONE CONTAINING CHEMICAL ADMIXTURES OF DIFFERENT PURPOSE / CEMENTINIO AKMENS SU SKIRTINGOS PASKIRTIES CHEMINIAIS PRIEDAIS PORINGUMO RODIKLIAI

2013 ◽  
Vol 5 (5) ◽  
pp. 530-535
Author(s):  
Lukas Venčkauskas ◽  
Mindaugas Daukšys
Keyword(s):  
Cement Paste ◽  
Cement Stone ◽  
Hardened Cement ◽  
Closed Porosity ◽  
Hardened Cement Paste ◽  
Chemical Admixtures ◽  
Average Size ◽  
The Impact ◽  
Plasticizing Admixture

The conducted research has established a complex influenceand the impact of separate chemical admixtures of differentpurpose on the parameters of the porosity of hardened cementpaste such as open and closed porosity, the average size of poresand the rates of pore inequality. According to the parametersof the porosity of hardened cement paste, on the basis of A. E.Sheikin’s methodology, the number of freezing-thawing cycleswas predicted. This research used plasticizing, viscosity modifyingand antifoaming admixtures. It has been found that, when theamount of plasticizing admixture in cement paste (W/C–0.45) isconstant and makes 1.1% of the cement mass, and the amountof viscosity modifying and antifoaming the admixture increasesfrom 0.1 to 0.6% and from 0.05 to 0.3% respectively, the openporosity of hardened cement paste varies between 30.21% and31.06%, while closed porosity varies between 5.39% and 6.22%.When the amount of the plasticizing admixture in cement paste(W/C–0.45) exceeds 1.1% of the cement mass, the open porosityof hardened cement paste increases by 1.4 times and closedporosity decreases by 2.5 times. While adding 0.1% of the viscositymodifying admixture to cement paste, the open porosityof hardened cement paste is increased by 1.5 times and closedporosity decreases by 2.4 times. The amount of 0.05% of thecement mass of the antifoaming admixture results in the increasedopen porosity of hardened cement paste by 1.5 times and reducedclosed porosity by 3.5 times. Santrauka Tyrimo metu nustatyta kompleksinė bei atskirų skirtingos paskirties cheminių priedų įtaka cementinio akmens poringumo rodikliams – atvirajam ir uždarajam poringumui, vidutinio porų dydžio ir porų vienodumo rodikliams. Tyrimuose naudoti cheminiai priedai: plastifikuojantis, klampą modifikuojantis ir mišinyje susiformavusias oro poras suardantis priedas. Nustatyta, kad cemento tešloje (V/C – 0,45) esant pastoviam plastifikuojančio priedo kiekiui – 1,0 % cemento masės, klampą modifikuojančio priedo kiekiui kintant nuo 0,1 iki 0,6 %, o mišinyje susiformavusias oro poras suardančio priedo kiekiui kintant nuo 0,05 iki 0,3 %, cementinio akmens atvirasis poringumas svyruoja nuo 30,21 iki 31,06 %, o uždarasis – nuo 5,39 iki 6,22 %. Cemento tešloje viršijus plastifikuojančio priedo 1,1 % cemento masės, cementinio akmens atvirasis poringumas padidėja apie 1,4 karto, o uždarasis poringumas sumažėja apie 2,5 karto. Pridėjus į tešlą 0,1 % cemento masės klampą modifikuojančio priedo, cementinio akmens atvirasis poringumas padidėja apie 1,5 karto, uždarasis poringumas sumažėja apie 2,4 karto. Oro poras suardančio priedo kiekis 0,05 % cemento masės cementinio akmens atvirąjį poringumą padidina apie 1,5 karto, uždarąjį poringumą sumažina apie 3,5 karto.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

The Research on Preparation of Binding Material and Concrete with Desulphurization Gypsum

2014 ◽  
Vol 697 ◽  
pp. 17-20
Author(s):  
Ping Tan
Keyword(s):  
Environmental Pollution ◽  
Bending Strength ◽  
Experimental Results ◽  
Cement Stone ◽  
Waste Sludge ◽  
Binding Material

The binding material and concrete are prepared by desulphurization gypsum, cement, stone, sand and admixture. The performances of binding material are studied in the paper. The experimental results showed that it is absolutely feasible to prepare binding material by using cement, desulphurization gypsum and superplasticizer after drying and screening of desulphurization gypsum. The binding material was prepared by adding desulphurization gypsum replacing 10 percent cement and superplasticizer. the cement micellae compressive and bending strength of the binding material can meet the standard requirements of P.O42.5 and the binding material’s set time and soundness are up to standard. The concrete was prepared by adding desulphurization gypsum replacing 30 percent cement and superplasticizer. The concrete’s strength is up to standard of the C30 concrete, and its impermeability meets the requirement of P12. To execute the research can not only massively use waste sludge desulphurization gypsum but also solve environmental pollution.

Bending Strength and Fracture Behaviour of Metal-Ceramic Interpenetrating Phase Composites Manufactured by Using Semi-Solid Forming Technology

2022 ◽  
Vol 327 ◽  
pp. 111-116
Author(s):  
Laura Schomer ◽  
Kim Rouven Riedmüller ◽  
Mathias Liewald
Keyword(s):  
Bending Strength ◽  
Fracture Behaviour ◽  
Structural Characteristics ◽  
Process Window ◽  
Metallic Material ◽  
Forming Technology ◽  
Metal Ceramic ◽  
Semi Solid ◽  
The Impact ◽  
Interpenetrating Phase Composites

Interpenetrating Phase Composites (IPC) belong to a special category of composite materials, offering great potential in terms of material properties due to the continuous volume structure of both composite components. While manufacturing of metal-ceramic IPC via existing casting and infiltration processes leads to structural deficits, semi-solid forming represents a promising technology for producing IPC components without such defects. Thereby, a solid open pore body made of ceramic is infiltrated with a metallic material in the semi-solid state. Good structural characteristics of the microstructure as the integrity of the open-pore bodies after infiltration and an almost none residual porosity within the composites have already been proven for this manufacturing route within a certain process window. On this basis, the following paper focuses on the mechanical properties such as bending strength of metal-ceramic IPC produced by using semi-solid forming technology. Thereby, the impact of the significant process parameters on these properties is analysed within a suitable process window. Furthermore, a fractographic analysis is carried out by observing and interpreting the fracture behaviour during these tests and the fracture surface thereafter.

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