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1
Fontaine, Marie-Laure, Christèle Combes, Thierry Sillam, Gérard Dechambre, and Cristian Rey. "New Calcium Carbonate-Based Cements for Bone Reconstruction." Key Engineering Materials 284-286 (April 2005): 105–8. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.105.
Повний текст джерелаАнотація:
The feasibility of calcium carbonate-based cements involving the re-crystallization of metastable calcium carbonate varieties has been demonstrated. Two cement compositions were obtained by mixing either calcium carbonate phases (cement A) or a calcium carbonate and a calcium phosphate phase (cement B) with an aqueous media. These cements set and hardened after 30 minutes and 90 minutes respectively. The final composition of cement A was calcite and aragonite whereas cement B lead to a carbonated apatite analogous to bone mineral. Despite poor mechanical properties the presence of a high carbonate content in the final phase might be of interest to increase the cement resorption rate and to favour its replacement by bone tissue. First assays of implantation performed on fresh anatomical pieces (fresh cadavers) at 37°C revealed important advantages of such cement compositions: easiness of use, rapid setting, good adhesion to bone, very good homogeneity and stability of the cement.
2
GHABEZLOO, SIAVASH. "MULTISCALE MODELING OF THE POROELASTIC PROPERTIES OF VARIOUS OIL-WELL CEMENT PASTES." Journal of Multiscale Modelling 02, no. 03n04 (September 2010): 199–215. http://dx.doi.org/10.1142/s1756973710000412.
Повний текст джерелаАнотація:
Evaluation of the poroelastic properties of oil-well cement paste is essential for prediction of the performance of the cement sheath during the life of a well. A multiscale homogenization model is used to evaluate the poroelastic properties of different classes of oil-well cement paste. The model has been calibrated in a previous work based on the results of a laboratory study on a hardened class G cement paste. A hydration model is used to evaluate the volume fractions of different microstructure phases of cement paste based on the chemical composition of clinker and the water-to-cement ratio. Typical chemical compositions of API class A to class H oil-well cements with their corresponding water-to-cement ratios are used to evaluate the poroelastic parameters such as drained bulk modulus, Biot coefficient, Skempton coefficient, etc. The results show that the difference in the chemical compositions of these cements has not an important effect on the variations of the poroelastic properties. Contrarily, the water-to-cement ratio has an important effect on the variations of these parameters.
3
Chulkova, I. L., I. A. Selivanov, and V. D. Galdina. "INFLUENCE OF THE SCOPE ADDITION ON THE STRUCTURE FORMATION OF THE CEMENT STONE BY THE METHOD OF QUANTITATIVE X-RAY PHASE ANALYSIS." Russian Automobile and Highway Industry Journal 16, no. 4 (September 8, 2019): 504–18. http://dx.doi.org/10.26518/2071-7296-2019-4-504-518.
Повний текст джерелаАнотація:
Introduction. The processes of structure formation of cement compositions and the development of effective technologies of building materials is an urgent task for building material science. The use of large-scale man-made product of pulp and paper enterprises – osprey as a fibrous filler in organic and mineral compositions is the successful decision of the problem. The paper analyzes the ways of using osprey in the building materials’ production. The aim of the research is to study the osprey influence on the processes of structure formation of cement stone by quantitative x-ray phase analysis.Materials and methods. The organic and mineral compositions were obtained on the basis of portland cement and osprey. The authors studied the compositions’ phase of osprey, portland cement and the processes of cement stone structure formation in organ and mineral compositions by quantitative x-ray phase analysis.Results. The authors determined the compositions’ phase of mineral impurities of osprey, cellulose, cement, cement stone, organic and mineral compositions and two compositions containing 25 and 75% by weight.Discussion and conclusions. The osprey application as a filler in the organic and mineral composition causes inhibition of processes of cement hydration. The presence of osprey in the hardening organic and mineral composition leads to a change in the composition and structure of the cement stone in comparison with the phase composition of the cement stone without additives. The result of these changes is a significant increase in the amount of calcite, waterite and a significant decrease in the amount of portland. The authors establish that the effective joint work of the reinforcing component of the osprey with the cement matrix is possible with a limited amount of osprey in organic and mineral compositions.
4
Sanytsky, Myroslav, Tetiana Kropyvnytska, and Roman Kotiv. "Modified Plasters for Restoration and Finishing Works." Advanced Materials Research 923 (April 2014): 42–47. http://dx.doi.org/10.4028/www.scientific.net/amr.923.42.
Повний текст джерелаАнотація:
The paper is devoted to the research and development of modified plasters for restoration and finishing works based on decorative multicomponent cements containing white Portland cement and supplementary cementitious materials (silica fume, metakaolin and fine ground limestone). This cements are similar to Roman cement by their chemical composition. The use of optimal granulometry of decorative multicomponent cements provide directed formation of microstructure of the cement matrix with the formation of stable hydration products. Compositions of modified plasters by the criterions of workability and compressive strength were designed. Physico-chemical modification of plaster by complex air-entraining admixture allows to obtain high-quality modified plasters with improved quality parameters.
5
Bediako, Mark, and Eric Opoku Amankwah. "Analysis of Chemical Composition of Portland Cement in Ghana: A Key to Understand the Behavior of Cement." Advances in Materials Science and Engineering 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/349401.
Повний текст джерелаАнотація:
The performance of Portland cement in concrete or mortar formation is very well influenced by chemical compositions among other factors. Many engineers usually have little information on the chemical compositions of cement in making decisions for the choice of commercially available Portland cement in Ghana. This work analyzed five different brands of Portland cement in Ghana, namely, Ghacem ordinary Portland cement (OPC) and Portland limestone cement (PLC), CSIR-BRRI Pozzomix, Dangote OPC, and Diamond PLC. The chemical compositions were analyzed with X-Ray Fluorescence (XRF) spectrometer. Student’st-test was used to test the significance of the variation in chemical composition between standard literature values and each of the commercial cement brands. Analysis of variance (ANOVA) was also used to establish the extent of variations between chemical compositions and brand name of the all commercial Portland cement brands. Student’st-test results showed that there were no significant differences between standard chemical composition values and that of commercial Portland cement. The ANOVA results also indicated that each brand of commercial Portland cement varies in terms of chemical composition; however, the specific brands of cement had no significant differences. The study recommended that using any brand of cement in Ghana was good for any construction works be it concrete or mortar formation.
6
Mihailescu, Dan, Dana Nicoleta Mihai, Liliana Savin, Lavinia Vasiliu, Victor Grigorescu, Alexandru Patrascu, and Marcel Ionel Popa. "Polymeric Biomaterials with Complimentary Role in Joint Endoprosthesis. II. Compositional and morpho-structural analysis." Materiale Plastice 56, no. 3 (September 30, 2019): 611–15. http://dx.doi.org/10.37358/mp.19.3.5239.
Повний текст джерелаАнотація:
Successfully used in bone surgery for more than 65 years, self-hardening organic cements (CCOs), in particular acrylic cements, are today, the most advanced complementary biomaterials used in articular endoprosthesis. One of the strategies for obtaining of performing anchorage of artificial implants is to develop new acrylic cements with improved physical, chemical and biomechanical characteristics. The aim of this paper was to identify the compositional and morpho-structural changes of acrylic cements induced by the composition of the liquid phase of the material. Such changes influence the potential to generate the physical bonds responsible for fixation and stabilization of endoprosthesis. The samples studied had different compositions due to the mixture of acrylic monomers, methyl methacrylate (MMA) and butyl acrylate (BuA) in the liquid component of cement. The MMA / BuA ratio varied between 1/0 v / v and 1/4 v / v. Changes in the composition and morphology of cement samples have been highlighted by ESCA (Electron Spectroscopy for Chemical Analysis), EDX (Energy-Dispersive X-ray Spectroscopy), IR spectroscopy and SEM images. The obtained data show that minor changes in cement composition can significantly influence morpho-structural characteristics such as pore size and their distribution in the mass of fixing material.
7
Kozlova, Irina, Olga Zemskova, and Vyacheslav Semenov. "The Effect of Fine Dispersed Slag Component on the Slag Portland Cement Properties." Materials Science Forum 1011 (September 2020): 103–8. http://dx.doi.org/10.4028/www.scientific.net/msf.1011.103.
Повний текст джерелаАнотація:
Cement compositions based on slag Portland cement and fine dispersed slag component are considered. It has been established that the introduction of 1-3% fine slag obtained as a result of ultrafine grinding in a jet mill into the slag Portland cement composition provides an increase in the strength and structural characteristics of cement stone from the first day of hardening, which is important for slag cements. To ensure the fine dispersed slag particles’ stabilization in the cement matrix, the cement compositions were sealed with water with the addition of a plasticizer on either sulfa-naphthalene formaldehyde or polycarboxylate substrates in an amount of 0.5% of the cement composite content. In the research course it was found that in the initial stages of hardening and grade age, the strength of the samples containing a fine dispersed slag component and a sulfa-naphthalene formaldehyde-based plasticizer increased by 20%. When the cement composition is mixed with water with a polycarboxylate-based plasticizer, an increase in strength in the initial period of hardening by 60% is noted, at the vintage age - by 30%. At the same time, the porosity of the samples based on slag Portland cement with the addition of fine dispersed slag and one of the plasticizers in the initial period was reduced by 16-21%, at the vintage age - by 33-35%.
8
Zagoronyuk, L., S. Rahimbaev, D. Sumskoy, and V. Ryzhikh. "FEATURES OF THE PROCESSES OF HYDRATION OF BINDING COMPOSITIONS USING WASTE OF EXPANDED PERLITE SAND." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, no. 11 (December 4, 2020): 75–88. http://dx.doi.org/10.34031/2071-7318-2020-5-11-75-88.
Повний текст джерелаАнотація:
The results of studying the processes of hydration of binder compositions obtained at different ratios of cement and waste of expanded perlite sand (from 5 to 10%), in a vortex jet mill, under different modes of mechanical and chemical activation - from one to three passes are presented. Comprehensive studies of hydration products by X-ray phase analysis and electron microscopy indicate that the use of highly dispersed wastes from the production of expanded perlite sand in binding compositions allows an increase in the content of hydrated neoplasms due to an increase in the degree of hydration of the main clinker phases, as well as due to the pozzolanic activity of these wastes. The contact zone between the hydrated compounds and the remnants of the grains of the original cements has a special effect on the formation of a high-strength structure of the cement stone. The structure formation of a cement stone depends on a number of factors, which can be influenced by various technological methods. When designing compositions of cement composites, it is necessary to ensure that hydration products in the created system are present along with low-basic calcium hydrosilicates and high-basic ones. Their ratio should be such that carbonization does not reduce the volume of the formed crystalline phase of the cement stone. The composition of the hydration products determines the level of supersaturation of the solution, the type and number of impurities soluble in water, the duration of the hydration process, etc. The chemistry of the reactions of the hydrated system changes accordingly. It is found that the intensity of the diffraction maxima, indicating the presence of highly basic calcium hydrosilicates in the compositions that underwent mechanical activation, increases by 18% in comparison with the ordinary PC. The strength characteristics of Portland cements, which have undergone mechanical activation, increase up to 15% compared to the original PC. The most rational binder composition is established in terms of composition (No. 6), mechanical activation and maximum compressive strength at 28 days of age – 69.1 MPa.
9
Rodin, Alexander, Sergej Karpushin, and Vasiliy Smirnov. "Cement Composites’ Biostability." Materials Science Forum 1011 (September 2020): 171–78. http://dx.doi.org/10.4028/www.scientific.net/msf.1011.171.
Повний текст джерелаАнотація:
The studies to establish the species composition of micro-mycetes inhabiting the surface of cement composites after aging in sea water have been carried out. Cement stone made on the basis of Portland cement clinker, a mineral additive and a fungicidal preparation was considered as the studied material. To determine the materials’ fouling by microorganisms, their species composition, imprints and sampling methods were used. A change in the species composition of mycobiota isolated from the cement composites’ surface modified with sodium sulfate and sodium fluoride depending on the amount of active filler, gypsum, and biocidal additives was experimentally revealed. The effectiveness of using the biocidal cement composites with an active mineral additive has been confirmed. It was found that the composites on the developed compositions showed higher resistance compared to the materials on ordinary cement. The compositions modified with biocidal additives showed a fungicidal effect.
10
Guryanov, A. M., S. F. Korenkova, and Yu V. Sidorenko. "STRUCTURE FORMATION PROCESS OF HYDRATED PORTLAND CEMENT COMPOSITIONS: NANOSCALE LEVEL CONTROL." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 3 (June 15, 2017): 77. http://dx.doi.org/10.17770/etr2017vol3.2618.
Повний текст джерелаАнотація:
Durability of cement-like construction materials, as well as durability of cement stone, depends on their humidity resistance, frost resistance, corrosion resistance. All of these properties depend not only on the composition of the original clinker, but also on structural organization at micro-and nanoscale level of hydrated portland cement compositions. In this research the authors used the method of small-angle neutron scattering to define structural parameters of hydrated portland cement compositions on nanoscale level, distribution of calcium hydrate silicate nanoparticles in size, medium nanoparticles radius, fractal dimension. It is shown, that introduction of modifying nanoadditives into portland cement compositions affects structural parameters of a cement stone. The following nanoadditives were used: of artificial (alpha aluminium oxide, gamma aluminum oxide) and of anthropogenic (carbonate and alumo-alkaline sludges) origin, as well as integrated nanoadditives containing surfactants. The change in structural parameters of portland cement compositions with nanoadditives in the process of hydration is investigated. It is shown that use of nanoadditives allows to control the process of forming the structure of hydrated portland cement composition on the nanoscale level, directly affect the values of structural parameters and, as a result, modify properties of cement stone.
11
Kapustin, F. L., A. A. Ponomarenko, and V. N. Oleinik. "Sulfoaluminate Cements Composition and Properties." Solid State Phenomena 265 (September 2017): 734–37. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.734.
Повний текст джерелаАнотація:
The chemical and mineral composition, physico-mechanical properties of sulfoaluminate cements of various classes of strength manufactured in China which are used in Russia to build and repair buildings and structures have been considered. It is shown that the sample sulfoaluminate cement depending on the strength class differ not only in chemical and mineral compositions, but also in their hydrophysical properties, kinetics of dissipation and hardening of cement, and hydration products. It is established that with the increasing strength class of the cement content it has calcium increases, the adhesion of the cement paste is slowed down, the duration of heat dissipation increases, the temperature dissipation is reduced, the hardening of the cement stone slows down.
12
Korohodska, A. N., G. N. Shabanova, S. M. Logvinkov, O. V. Khrystych, and M. M. Volobuev. "Calculation of eutectics temperatures and compositions of multicomponent sections of the system (Mg, Ca, Sr, Ba)O—Al2O3—Cr2O3." Scientific research on refractories and technical ceramics 121 (December 30, 2021): 94–102. http://dx.doi.org/10.35857/2663-3566.121.10.
Повний текст джерелаАнотація:
With change in the structure of metallurgical production in Ukraine, the range of used refractory materials is expanding: the share of unshaped highquality refractories is growing, since this eliminates the time-consuming and energy-consuming operation of firing piece products, and also simplifies the operation of creating a lining layer. To establish the maximum possible operating temperature of materials developed on the basis of compositions of the optimal regions of multicomponent oxide system (Mg, Ca, Sr, Ba)O— Al2O3—Cr2O3, it was necessary to calculate the temperatures and compositions of the eutectics of binary, ternary and four-component sections, which was the purpose of this study.
For calculations in binary sections, the Epstein — Howland method is most acceptable, and in three- and four-component sections — the solution of nonlinear equations system. It was found that to obtain a refractory unshaped material based on calcium aluminium chromite cement with periclase as a filler, it is necessary to adjust the phase composition of the cement towards an increased CaCr2O4 content, and the total composition must contains at least 75 wt. % periclase or magnesium spinel. In addition, in the case of alumina hydrates formation as a result of cement hydration processes, magnesium spinel will be synthesized as part of a refractory unshaped material during service. To obtain refractory unshaped materials based on strontium aluminium chromite cement and periclase as filler, it is necessary to increase the SrAl2O4 content and minimize the Sr3Al2O6 content in the cement composition, while the filler content in the composition can vary within wide limits, since the melting temperature of such compositions will be more than 1700 °C. To create refractory unshaped materials based on barium aluminium chromite cements, it is necessary to increase the content of BaAl2O4 in the cement composition as the most hydraulically active and refractory component and the composition of the composite material should be low- or ultra-low-cement in order to increase the operating temperature. In addition, in the case of chromium hydroxides formation during the hydration of aluminium chromite cement, chromium spinel will be synthesized in the composition during service, increasing the refractoriness of resulting composition. Thus, by varying the type and phase composition of cement and the ratio of cement and aggregates in the concrete composition, it is possible to obtain unshaped materials with a wide operating temperature range for use in heat-stressed areas of high-temperature aggregates.
13
Kryvenko, Pavlo, Sergii Guzii, Oleksandr Kovalchuk, and Volodymyr Kyrychok. "Sulfate Resistance of Alkali Activated Cements." Materials Science Forum 865 (August 2016): 95–106. http://dx.doi.org/10.4028/www.scientific.net/msf.865.95.
Повний текст джерелаАнотація:
One of the most important questions of concrete durability is increasing of corrosion resistance of cement stone and materials on his basis. Perspective way of solving such problems is using of alkali activated binders.Two cement systems were investigated to obtain different materials for different application - geocement system for repair materials and protective coatings and fly ash alkali activated hybrid cement for corrosion resistant common cements and concretes.It was studied sulfate resistance of fly ash alkali activated cements after 3 years of storing in aggressive environments like 5 and 10 % solutions of sodium sulfate, 2 and 4 % solutions of magnesium sulfate and sea salt solution. It was shown that fly ash containing cements are characterized by high corrosion resistance (coefficient of corrosion resistance after 3 years of storing in aggressive environment is in the ranges 0.8...1.0) comparing with clinker cements (0.45...0.88). Shown, that high sulfate resistance of cements under study in time is caused by graduate structure development and crystallization of new formations with compacting structure of material that effect on service properties of materials.High corrosion resistance of geocement compositions (coefficient of corrosion resistance 0.9-1.05) in sulfate environment is possible because of formation of faujasite, chabasite, mordenite and nozean phases in the structure of materials. Optimal composition of geocement compositions were developed according mathematical planning of experiments and tested.
14
Konovalova, N. A., O. N. Dabizha, P. P. Pankov, and E. A. Rush. "Utilization of Hydrolysis Lignin in Compositions Soil-Cements." Ecology and Industry of Russia 23, no. 11 (November 13, 2019): 32–37. http://dx.doi.org/10.18412/1816-0395-2019-11-32-37.
Повний текст джерелаАнотація:
The article investigated the compositions of road-building materials containing screenings of rock crushing, Portland cement, hydrolyzed lignin, modified by the stabilizing additive “Element”. The road-building compositions containing screenings of rock crushing, Portland cement, hydrolyzed lignin modified with the stabilizing additive "Element" were investigated. The optimal content of raw materials has been established, which allows to obtain soil-cements with a strength mark of at least M 60 - M 75. Using a model experiment, it was shown that the stabilizing additive “Element” is active and can interact with each of component of the raw materials. Using the methods of scanning electron microscopy, infrared spectroscopy, X-ray phase analysis, it has been experimentally shown that the processes of hydration, carbonization and increasing the connectivity of orthosilicate anions play a significant role in the structure formation of soil-cements.
15
Ignatova, O. A., and A. A. Dyatchina. "Influence of High-Calcium Ash Composition on the Composite Binders’ Properties." Solid State Phenomena 316 (April 2021): 1019–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.316.1019.
Повний текст джерелаАнотація:
The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.
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Золотых, Сергей, Sergey Zolotykh, Дмитрий Сумской, Dmitriy Sumskoy, Лилия Загороднюк, Liliya Zagorodnyuk, Елена Канева, and Elena Kaneva. "MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 2, no. 3 (February 9, 2017): 9–18. http://dx.doi.org/10.12737/article_58db88f8dac3d.
Повний текст джерелаАнотація:
Zagorodnuk L.H., Sumy D.A., Golden S.V., Kaneva E.V.
MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL
By electron microscopy to study the microstructure of the cement stone made from Portland cement and activated binders of the compositions in the vortex jet mill. It was found that the open pores of the cement and cementitious compositions prepared using perlite fillers, always filled with tumors, at different stages of collective growth. The microstructure of cementitious compositions has a dense structure by rationally selected composition, effective use of mineral filler - perlite waste, creating additional support for the formation of the internal microstructure of the composite, mechanical activation raw mixture, allowing to obtain composites with desired properties.
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Золотых, Sergey Zolotykh, Сумской, Dmitriy Sumskoy, Загороднюк, Liliya Zagorodnyuk, Канева, and Elena Kaneva. "MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 2, no. 3 (April 4, 2017): 9–18. http://dx.doi.org/10.12737/article_58e23e09e92025.32814168.
Повний текст джерелаАнотація:
Zagorodnuk L.H., Sumy D.A., Golden S.V., Kaneva E.V.
MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL
By electron microscopy to study the microstructure of the cement stone made from Portland cement and activated binders of the compositions in the vortex jet mill. It was found that the open pores of the cement and cementitious compositions prepared using perlite fillers, always filled with tumors, at different stages of collective growth. The microstructure of cementitious compositions has a dense structure by rationally selected composition, effective use of mineral filler - perlite waste, creating additional support for the formation of the internal microstructure of the composite, mechanical activation raw mixture, allowing to obtain composites with desired properties.
18
Mazmanyan, Smbat V., Gayane Papyan, Tamara Sargsyan, Armine Baghdagyulyan, Tatevik Paytyan, and Hovsep Hoveyan. "The Influence of Cement Grain Structure on Physical and Mechanical Properties of Cement." Key Engineering Materials 906 (January 11, 2022): 31–37. http://dx.doi.org/10.4028/www.scientific.net/kem.906.31.
Повний текст джерелаАнотація:
The paper presents the study of morphological characteristics of cement particles and reveals the influence of the structure of the cement grain composition on the physical and mechanical properties of cement. The following portland cements produced by “Hrazdan Cement Corporation” LLC, which have 52,5 MPa and 42,5 MPa compressive strength limit and hydraulic additives up to 20% and over 20% have been used for the experiment: CEM II/ A-P 42,5N, CEM II/ B-P 42,5N, CEM II/A-Q 42,5N, CEM II/B-Q, CEM II/A-L 42,5N, CEM II/B-L 42,5N, CEM II/A-M 42,5N, CEM II/B-M, CEM III/A-S 42,5N and CEM III/B-S 42,5N. Grain distribution in all the samples has been studied using a CILAS laser analyzer. Microscopic analysis of all the fractions has been carried out with the help of James Swift optical microscope. The given grain compositions have undergone chemical analysis in compliance with the requirements of interstate ISO 5382-2019 and ASTM C114-18 standards. Experimental studies and analyses show that the cements with microsilica have the highest value of water-cement ratio-W/C = 0.7, the highest by volume compression are the cements with volcanic slag-4 mm, the beginning of the bonding period is the longest in case of limestone cements - t = 140 minutes, followed by microsilica cements, and in third place there are artificial slag cements, the results of which are as follows: 130; 124 minutes. The summarized data show that microsilica cements have the highest compressive strength limit among the cements having the same percentage of additives-48.87 MPa.
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Xie, Pin, Ping Gu, Yan Fu, and J. Beaudoin James. "5447564 Conductive cement-based compositions." Cement and Concrete Composites 18, no. 6 (January 1996): 459–60. http://dx.doi.org/10.1016/s0958-9465(97)89853-8.
Повний текст джерела
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Sumskoi, D. A. "Heat-insulating mortar based on composite binder." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 2 (October 2, 2018): 283–89. http://dx.doi.org/10.20914/2310-1202-2018-2-283-289.
Повний текст джерелаАнотація:
The article presents the results of studies on obtaining a heat-insulating solution obtained by grinding. The binding compositions were synthesized at various ratios of cement and waste products of perlite sand in ajet mill under different grinding regimes. The features of grinding processes have been studied and technological and physicomechanical properties of the resulting binding compositions have been determined. The microstructure of cement stones obtained from activated Portland cement and binding compositions in ajet mill was studied by electron microscopy. It is established that open pores of cement-binding compositions prepared using perlitic fillers are filled with neoplasms and perlite grains have a plate-prismatic shape, which is clearly seen in micrographs. The microstructure of binding compositions has a dense structure due to a rationally selected composition, the use of an effective mineral filler, which creates additional substrates to form the internal microstructure of the composite. A comparative X-ray diffraction analysis of hydrated plain cement and binding composition was carried out and it was established that hydrated cement and binding composition are identical in mineral composition, having Ca hydroalumates, Ca (OH)2, CSH, and low amounts of ettringite. A distinctive feature of the diffractograms is the significant amorphization of the binding composition. The range of the optimal ratio of cement to perlite was found to be 1:9; 1:11; 1:13. A heat-insulating solution based on composite binder and expanded perlite aggregate (1:11) with a density of 1200 kg / m3 and a strength of 2.5 MPa was obtained. Modification of the solution by additives of superplasticizer; blowing agent; redispersible dispersion powder, it was possible to obtain a heat-insulating solution with a density of 973.11 kg/m3. Optimization of this solution with expanded polystyrene microspheres made it possible to obtain a density of the composite of 240-260 kg/m3 at a compressive strength of 1.05-1.15 MPa. The developed heat-insulating compounds have a reduced density and sufficient strength, which is the reason to recommend them for use in the manufacture of construction works.
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Krivenko, Pavlo, Igor Rudenko, Oleksandr Gelevera, and Natalia Rogozina. "OBTAINING DECORATIVE ALKALINE-ACTIVATED CEMENT BY USING SLAGS WITH A HIGH CONTENT OF IRON OXIDE." Collected scientific works of Ukrainian State University of Railway Transport, no. 198 (May 12, 2022): 30–40. http://dx.doi.org/10.18664/1994-7852.198.2021.256531.
Повний текст джерелаАнотація:
Decorative cements have always been in high demand in the construction industryand the demand for them and the requirements for their performance are constantly growing. Butdecorative cements based on white clinker Portland cement have the same disadvantages astraditional Portland cement, namely: high energy intensity, low environmental friendliness, highprice. Not all countries produce it and have to import it, which further increases its cost. White clinkercements do not always provide sufficient stability of decorative and operational characteristics ofmaterials based on them. Therefore, an alkali-activated slag cement, obtained using industrial waste,and on the basis of which white cement can be obtained, can act as an effective alternative. Pigmentedalkali-activated decorative cement has high strength, durability and a wide range of colors andshades, high adhesion to various substrates, durability. An obstacle to the widespread use of alkaliactivated slag cements as decorative ones with high whiteness characteristics ( 70 %) is the unstablechemical composition of the slags and, first of all, the different presence of iron oxides in it. In thiswork, the optimization of the compositions of alkali-activated slag decorative cements according to the criterion of whiteness, depending on the amount of iron oxide in the slag, is carried out. Phaseanalysis of decorative alkali-activated cements was carried out. It was found that the composition ofhydrated neoplasms is represented mainly by low-basic calcium hydrosilicates, hydroaluminosilicatephases of an alkaline and alkaline-alkaline earth composition, and gel-like products. Mathematicaldependencies have been obtained that make it possible to easily and quickly calculate the amountand type of bleaching additive, taking into account the presence of iron oxide in the slag in the rangeof 0,4...2,6 %, while ensuring the whiteness of the cement stone at least 70 %. The possibility ofobtaining pigmented cements of grades / class M400...M500 / 42,5R is shown. The heat release ofdecorative alkali-activated cements, depending on their composition, is 44,0...77,4 J/g and is at thelevel of heat release of Portland cements 32,5R...42,5R.
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Kovalchuk, Oleksandr, Valentina Grabovchak, and Yaroslav Govdun. "Alkali activated cements mix design for concretes application in high corrosive conditions." MATEC Web of Conferences 230 (2018): 03007. http://dx.doi.org/10.1051/matecconf/201823003007.
Повний текст джерелаАнотація:
This paper covers the results of development of corrosion resistant ash alkali-activated cements based on regulation of phase composition of the hydration products through changing the alkali content, content of calciumcontaining cement constituents resulting in the increase strength and density of the cement stone. The results of study suggested to conclude that the cement compositions with predominance in the hydration products of weakly soluble low basic hydrosilicates of calcium, hydrogarnets and minerals similar to natural hydroaluminates exhibited the highest corrosion resistance. The results of comparison suggested to draw a conclusion that the alkali-activated cements Types APC III-400 and ACC V-400, according to National Ukrainian Standard DSTU B V.2.7, had high corrosion resistance compared to that of OPC, thus allowing to recommend the developed cements for the concretes intended for use in aggressive environments, inclusive of sodium and magnesium sulphates and others. Coefficients of corrosion resistance of concretes are higher than 1 after even 42 months.
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Kapustin, Fedor L., N. N. Bashkatov, and Rudolf Hela. "The Effect of Opal-Containing Rocks on the Properties of Lightweight Oil-Well Cement." Solid State Phenomena 325 (October 11, 2021): 47–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.325.47.
Повний текст джерелаАнотація:
When constructing deep wells for oil and gas production in difficult geological conditions, special lightweight oil-well cements are used. To reduce the density and water separation of the cement slurry as well as to increase the strength, corrosion resistance of cement stone and the quality of well cementing, opal-containing rocks, fly ash, microsphere and other lightening additives are introduced into the cement composition. The influence of sedimentary rocks, such as opoka, tripoli, and diatomite containing from 43 to 81% amorphous silica on the grindability, rheological and physical-mechanical properties of lightweight oil-well Portland cement has been studied. The twelve cement compositions with different content of additives (from 30 to 45%) that meet the requirements of the standard for density, spreadability, water separation, thickening time and flexural strength were selected. The introduction of 45% diatomite or tripoli significantly reduces the duration of cement grinding, provides the cement slurry with water-cement ratio of 0.9 with better density and flexural strength, respectively, 1480 kg/m3 and 1.1–1.5 MPa.
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Moon, Ho-Jin, Jung-Hwan Lee, Joong-Hyun Kim, Jonathan C. Knowles, Yong-Bum Cho, Dong-Hoon Shin, Hae-Hyoung Lee, and Hae-Won Kim. "Reformulated mineral trioxide aggregate components and the assessments for use as future dental regenerative cements." Journal of Tissue Engineering 9 (January 2018): 204173141880739. http://dx.doi.org/10.1177/2041731418807396.
Повний текст джерелаАнотація:
Mineral trioxide aggregate, which comprises three major inorganic components, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A), is promising regenerative cement for dentistry. While mineral trioxide aggregate has been successfully applied in retrograde filling, the exact role of each component in the mineral trioxide aggregate system is largely unexplored. In this study, we individually synthesized the three components, namely, C3S, C2A, and C3A, and then mixed them to achieve various compositions (a total of 14 compositions including those similar to mineral trioxide aggregate). All powders were fabricated to obtain high purity. The setting reaction of all cement compositions was within 40 min, which is shorter than for commercial mineral trioxide aggregate (~150 min). Over time, the pH of the composed cements initially showed an abrupt increase and then plateaued (pH 10–12), which is a typical behavior of mineral trioxide aggregate. The compression and tensile strength of the composed cements increased (2–4 times the initial values) with time for up to 21 days in an aqueous medium, the degree to which largely depended on the composition. The cell viability test with rat mesenchymal stem cells revealed no toxicity for any composition except C3A, which contained aluminum. To confirm the in vivo biological response, cement was retro-filled into an extracted rat tooth and the complex was re-implanted. Four weeks post-operation, histological assessments revealed that C3A caused significant tissue toxicity, while good tissue compatibility was observed with the other compositions. Taken together, these results reveal that of the three major constituents of mineral trioxide aggregate, C3A generated significant toxicity in vitro and in vivo, although it accelerated setting time. This study highlights the need for careful consideration with regard to the composition of mineral trioxide aggregate, and if possible (when other properties are satisfactory), the C3A component should be avoided, which can be achieved by the mixture of individual components.
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TABATABAEE MORADI, Seyyed Shahab, Nikolay NIKOLAEV, and Tatiana NIKOLAEVA. "Development of spacer fluids and cement slurries compositions for lining of wells at high temperatures." Journal of Mining Institute 242 (May 8, 2020): 174. http://dx.doi.org/10.31897/pmi.2020.2.174.
Повний текст джерелаАнотація:
Article is devoted to creation of new compositions of process solutions for lining of directional wells at high temperatures. Developed compositions provide high durability characteristics of cement stone. It is shown that with an increase in packing density of cementing slurry components durability characteristics increase and porosity and permeability of cement stone decrease, whereas an increase in temperature and pressure leads to a significant increase in compressive and bending durability, which is associated with presence of quartz in them.
It has been established that introduction of special structure-forming additives to the composition of developed cementing solutions allows formation of sedimentation-resistant cement systems that can provide an increase in durability characteristics of cement stone and, in general, quality lining of directional wells. Study of rheological properties of developed cementing compositions showed that the systems have high yield strength at increased temperatures and pressures.
Developed compositions of water-based spacer fluids increase the cleansing degree for both casing and rocks surfaces from mud and clay cake residues, which improves the cementing quality of oil and gas wells.
Mechanism for increasing the washing ability of spacer fluids and durability characteristics of cement stone, depending on composition and properties of their constituent components, is disclosed.
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Maksimova, I. N., N. I. Makridin, Anna V. Dergunova, and Yu V. Babenkova. "Effect of Cement Paste Preparation Procedure and Cement Stone Age on its Phase Composition." Key Engineering Materials 887 (May 2021): 473–79. http://dx.doi.org/10.4028/www.scientific.net/kem.887.473.
Повний текст джерелаАнотація:
Self-levelling and self-consolidating concrete mixtures formed with the use of superplasticizers are worthwhile for the manufacture of reinforced concrete structures. It is important to evenly distribute not only the mixing water in the system, but also the dissociated plasticizer ions for cement dispersed compositions with plasticizing additives. It is established that the optimal sequence of loading and mixing of the components of a cement composition is not only a promising direction for intensifying the manufacture of concrete building structures, but also a tool for improving the mechanical properties of cement brick and concrete made on its basis, as well as for increasing its durability and reliability. When superplasticizers are introduced into the pre-ground cement paste, the rheological properties of the compositions are improved, as well as the structure of the hardened composites. The given article is devoted to the study of the effect of the procedural factor and the duration of mixing of highly concentrated cement compositions with the addition of a superplasticizer based on naphthalene sulfonic acid (SP C-3) on the phase composition of hardened composites during various periods of hydration. Experimental results were obtained using the X-ray phase analysis method. Tested are 15 series of samples of cement stone with W/C ratio range between 0,18 and 0,27 and SP C-3 between 0 and 1.0 % by cement weight. Comparing the phase composition of cement stone after 28 days of hardening with that of 4,5 years, it was found that at first the C3SH2 phase, particularly enriched with calcium oxide, is formed, which decays over time and disappears in the 4,5-year hardening amples.
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Irbe, Zilgma, Dagnija Loca, Ivita Bistrova, and Liga Berzina-Cimdina. "Calcium Phosphate Bone Cements Reinforced with Biodegradable Polymer Fibres for Drug Delivery." Key Engineering Materials 604 (March 2014): 184–87. http://dx.doi.org/10.4028/www.scientific.net/kem.604.184.
Повний текст джерелаАнотація:
Conventional calcium phosphate bone cements are self setting water based pastes. Recently pre-mixed calcium phosphate bone cements have been proposed that have non-aqueous fluid as liquid phase of the paste. Such cements thus only start setting reaction in contact with body fluids. In this work the properties (cohesion, compressive strength, phase composition) of pre-mixed calcium phosphate cements based on α-tricalcium phosphate and calcium dihydrogen phosphate monohydrate are described. Properties of several cement compositions are examined and compared to properties of β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements. It was found that α-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements have higher compressive strength (10 - 15 MPa) than corresponding β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements (10 - 6 MPa). Out of examined cement paste liquids (glycerol, polyethylene glycol and polypropylene glycol) cements using glycerol as the liquid phase had higher compressive strength and are more cohesive.
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Irbe, Zilgma, Guna Krieke, Kristine Salma-Ancane та Liga Berzina-Cimdina. "Fast Setting Pre-Mixed Calcium Phosphate Bone Cements Based on α-Tricalcium Phosphate". Key Engineering Materials 604 (березень 2014): 204–7. http://dx.doi.org/10.4028/www.scientific.net/kem.604.204.
Повний текст джерелаАнотація:
Conventional calcium phosphate bone cements are self setting water based pastes. Recently pre-mixed calcium phosphate bone cements have been proposed that have non-aqueous fluid as liquid phase of the paste. Such cements thus only start setting reaction in contact with body fluids. In this work the properties (cohesion, compressive strength, phase composition) of pre-mixed calcium phosphate cements based on α-tricalcium phosphate and calcium dihydrogen phosphate monohydrate are described. Properties of several cement compositions are examined and compared to properties of β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements. It was found that α-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements have higher compressive strength (10 - 15 MPa) than corresponding β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate based cements (10 - 6 MPa). Out of examined cement paste liquids (glycerol, polyethylene glycol and polypropylene glycol) cements using glycerol as the liquid phase had higher compressive strength and are more cohesive.
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Szewczenko, Wiktor, and Galyna Kotsay. "Alkaline Activity of Portland Cement with Additives of Waste Glass." Materials 14, no. 6 (March 10, 2021): 1346. http://dx.doi.org/10.3390/ma14061346.
Повний текст джерелаАнотація:
The concept of the alkaline activity of powdered materials introduced into cement compositions has been proposed, along with methods for its determination. The possibility of using waste glass as an active additive to Portland cement was evaluated from the standpoint of alkaline activity. Replacing the Portland cement component with glass waste in the form of glass powder at amounts from 1 to 35% made it possible to maintain the cement composition’s alkaline activity at a level that met the standard requirements. The previously unknown effects of mixed alkali in Portland cement in the presence of glass waste are described. Portland cement has a high potassium alkaline activity; however, container glass has a high sodium alkaline activity and a fairly low potassium alkaline activity. When glass waste is introduced into the structure of cement compositions, potassium alkaline activity is reduced.
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Cahyanto, Arief, Elfira Megasari, Myrna Nurlatifah Zakaria, Nina Djustiana, Sunarso, Kosterman Usri, Dudi Aripin, Sri Tjahayawati, Marry Siti Mariam, and Sebastian Sunardhi Widyaputra. "Fabrication of Carbonate Apatite Cement as Endodontic Sealer." Key Engineering Materials 758 (November 2017): 61–65. http://dx.doi.org/10.4028/www.scientific.net/kem.758.61.
Повний текст джерелаАнотація:
Carbonate Apatite (CO3Ap) cement has been widely used for bone substitute. It is known that CO3Ap crystals have the close composition to natural bone. It is expected that CO3Ap cement may play an essential role in endodontics treatment, particularly as an endodontic sealer due to its potential to obturate root canal system to a more hermetic and stable environment. Therefore, the aim of this study is to fabricate CO3Ap cement as a new material for endodontic sealer. The CO3Ap cement sealer was prepared by mixing dicalcium phosphate anhydrous (DCPA), vaterite and calcium hydroxide [Ca(OH)2] with 0.2 mol/L Na2HPO4 containing 1% sodium carboxymethyl cellulose (NaCMC) and 32 µg thymoquinone, with liquid to powder ratio of 0.6. The set cement was incubated at 37°C under 100% relative humidity for 72 h. In this study, five compositions of powder ratio were prepared. The diametral tensile strength (DTS) evaluation indicated that CO3Ap cement made of 60% DCPA, 30% Vaterite and 10% Ca(OH)2 has the highest mechanical strength compared with the other compositions. X-ray diffraction (XRD) analysis of the set cement with the highest DTS value indicated that CO3Ap crystals were successfully formed. The set cement with the highest DTS value showed the highest density compared with the other compositions evidenced from scanning electron microscope (SEM) images. In conclusion, the CO3Ap cement was successfully fabricated by mixing DCPA, vaterite and Ca(OH)2. The CO3Ap cement prepared from 60% DCPA, 30% Vaterite and 10% Ca(OH)2 demonstrated the highest DTS value compared with the other compositions.
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Gornostaeva, E. Yu, N. P. Lukuttsova, and D. I. Dryazgov. "Improvement of Wood-Cement Composition Properties with Microsilica Additive." Materials Science Forum 992 (May 2020): 162–67. http://dx.doi.org/10.4028/www.scientific.net/msf.992.162.
Повний текст джерелаАнотація:
The properties and microstructure of wood-cement compositions (WCC) with microsilica (MS) additive for the manufacture of small-pieces wall products are studied. The extreme dependences of mean density, thermal conductivity and compressive strength on the content of microsilica additive are established. The mechanism of microsilica effect on wood-cement compositions is offered. Two interrelated factors (chemical and physical) could be distinguished at that. The first factor includes mainly the interaction of silicon dioxide with lime having released during hydration of calcium silicates, i.e. pozzolatic process. The second factor lies in the compaction of wood-cement compositions and the cement stone structure by means of cement hydration products and silica particles. It is established that introducing 20% of microsilica in the composition results in the maximum increase in ultimate compression strength (3 times). It can be explained not only by forming calcium hydrosilicates, uniformly and densely covering the wood aggregate, but by compacting effect of spherical microsilica inclusions, filling the space between the new cement stone formations and wood aggregate.
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Gildenhaar, Renate, Georg Berger, E. Lehmann, and Christine Knabe. "Development of Alkali Containing Calcium Phosphate Cements." Key Engineering Materials 361-363 (November 2007): 331–34. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.331.
Повний текст джерелаАнотація:
Commercially available calcium phosphate cements set by precipitation of nanoapatite or brushite. The goal of this study was to elucidate the most suitable conditions for forming cements from calcium potassium sodium phosphate. Furthermore, the behaviour of these cements after immersion in SBF and/or TRIS solution was investigated. Using varying additives resulted in differences in solubility kinetics. The XRD spectra of all investigated cement compositions displayed Ca2KNa(PO4)2 after setting. However, the various cement compositions differed with respect to apatite formation when immersed in TRIS buffer in and/or SBF solution. Therefore, when investigating calcium phosphate cements we consider it necessary to clearly differentiate between the phases which form after completion of the final setting time when these materials set in air, and the phases which form in a time dependant manner after immersion in different biological fluids.
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Timofeeva, A. S., A. A. Kozhukhov, and V. V. Fedina. "Investigation of the influence of granulometric composition of the aggregate and the content of the binder on the properties of refractory concrete." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, no. 5 (May 26, 2021): 580–86. http://dx.doi.org/10.32339/0135-5910-2021-5-580-586.
Повний текст джерелаАнотація:
Depending on the additives used, refractory concretes acquire the necessary properties: fire resistance, porosity, heat resistance, maximum application temperature, etc. The influence of the granulometric composition of the mullite aggregate and the content of the binder (cement) on the properties of refractory concrete was evaluated. MLS-62 was used as a filler (the content of the determining component Al2O3 was more than 62%), and Secar 71 high-alumina cement was used as a binder. To test the samples obtained from different granulometric compositions, the mullite aggregate was sieved in fractions (–6+3) mm, –3 mm. In the developed compositions of refractory concrete, these fractions were mixed in different percentages:(–6+3)/(–3). The cement content in the compositions varied by weight: 15%, 20%, 25%. The study was carried out in the factory laboratory, where samples of refractories of all the compositions were made by vibration pressing method. The resulting samples were dried at 110 °C and fired. It was found that after drying, samples with a cement content of 25% had the highest strength indicators content of 25% was the best result in terms of strength and shrinkage. Studies of the impact of the granulometric composition of the charge on the physical properties of refractory concrete showed that the highest strength indicators were exhibited by samples of refractory concrete with a percentage of fractions in the aggregate of 40/60 and 20/80, as well as with the highest amount of cement content in the composition – 25%.After firing at 800oC and 1300oC, the strength of the samples decreases. It was shown that the reason of this phenomenon was softening, mainly associated with dehydration of the binder. The refractory concrete obtained with the use of aggregate with a fractional composition of 20/80 and a cement.
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Salamanova, M., M. Nahaev, and B. Sarsenbaev. "DEVELOPMENT OF SPECIAL RECIPES OF BINDING COMPOSITIONS WITH IMPROVED PROPERTIES." Construction Materials and Products 3, no. 4 (November 2, 2020): 5–12. http://dx.doi.org/10.34031/2618-7183-2020-3-4-5-12.
Повний текст джерелаАнотація:
the ecological safety of earthly civilization suffers from the accumulation of huge volumes of industrial waste, the natural resource potential is decreasing, therefore, special attention is paid to the development of less costly and low energy-intensive technologies for obtaining new building materials, the implementation of which does not require high-temperature and expensive technological processing, and will allow the use of secondary and substandard raw materials.
The work presents the results of the development of special formulations of binder compositions of alkaline activation based on cement production wastes in the form of aspiration and clinker dust from electrostatic precipitators of rotary kilns and waste from the metallurgical industry - ferrosilicon additives in the form of active silica, which will allow obtaining new building materials with improved properties.
The paper investigates the properties of an alkaline cement paste and cement stone, reveals issues related to the theoretical foundations of the formation of the structure and strength of an artificial stone based on an alkaline activator. The research results, in our opinion, are certainly of practical importance for the construction industry, as the proposed formulations of clinker-free cements can partially replace expensive and energy-intensive Portland cement, making it possible to create strong and durable concrete and reinforced concrete structures
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Rubanov, Aleksandr, Nikolay Gorlenko, and Vladimir Vergasov. "Material and field impacts on cement compositions." MATEC Web of Conferences 143 (2018): 02002. http://dx.doi.org/10.1051/matecconf/201814302002.
Повний текст джерелаАнотація:
The paper studies the effect of combined field impact on cement compositions. The priority research direction involves creation of cement compositions and technologies that meet the requirements of technological availability and efficiency, environmental safety and sustainability, biocompatibility, economic efficacy and energy and resource saving. The paper proves that these criteria can be affected by material and field impacts on cement systems, which leads to considerable increase in strength of hardened cement paste, mortars and concretes. With this purpose, the paper presents detailed study on combined impact of ultrasound and magnetic field on grouting fluid of cement systems and strength of hardening systems in normal conditions. Compressive strength of cement and sand mortar was found to increase on average by 30-45%.
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Kirgiz, Mehmet Serkan. "Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/625350.
Повний текст джерелаАнотація:
Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement.
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Erofeev, Vladimir, Vladimir Kalashnikov, Sergei Karpushin, Alexander Rodin, Vasiliy Smirnov, Olga Smirnova, Marina Moroz, Vladimir Rimshin, Ilia Tretiakov, and Aleksandr Matvievskiy. "Physical and Mechanical Properties of the Cement Stone Based on Biocidal Portland Cement with Active Mineral Additive." Materials Science Forum 871 (September 2016): 28–32. http://dx.doi.org/10.4028/www.scientific.net/msf.871.28.
Повний текст джерелаАнотація:
The article considers innovative materials for construction. Using mathematical planning methods, we studied how the quantitative composition, the biocidal additive and gypsum content influence on the compressive and flexural strength and density of the composites. We found that the more gypsum in a composition the higher compressive and flexural strength of a specimen. So, with the greatest degree of compositions filling (fly ash – 20 mass fractions, gypsum – 11.2 mass fractions) maximum compressive strength is 72.5 MPa. We determined when the fly ash content rises up to 20 mass fractions per 100 mass fractions of clinker, flexural strength rises too and specimen density decreases. The developed compositions of biocidal cements recommended for use in the manufacture of materials, products and structures for buildings and constructions, operating in aggressive environments.
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Kazanskaya, Liliya, Nicolay Privalov, and Svetlana Privalova. "Fine ground granulated blast furnace slag for saving quantity of binder." E3S Web of Conferences 110 (2019): 01055. http://dx.doi.org/10.1051/e3sconf/201911001055.
Повний текст джерелаАнотація:
Nowadays, it is acknowledged that the use of mineral additives based on ground slag is one of ways of resource saving and improvement of technical properties of cement composites. Mineral additives with fineness similar to the Portland cement fineness are often used to replace part of Portland cement. Two kinds of ultra-fine ground granulated blast furnace slag that differ in composition and fineness were studied in the paper. Water-reduction due to effect of super plasticizer in slag-Portland cement compositions with amount of slag up to 70% was studied. The results of reduction of binder quantity per 1 kg of chemical admixture due to significant water-reduction are obtained and analysed. Correlations depending on kind, amount and fineness of slags, as well as depending on mineralogical composition of Portland cement were stated. The ultra-fine mineral additives based on ground slag with high specific surface area can be used for significant reduction of compositional binder.
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Ustinova, Yulia V., and Tamara P. Nikiforova. "Cement Compositions with the Chitosan Additive." Procedia Engineering 153 (2016): 810–15. http://dx.doi.org/10.1016/j.proeng.2016.08.247.
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Pushkarova, Kateryna, Maryna Sukhanevych, and Artur Martsikh. "Using of Untreated Carbon Nanotubes in Cement Compositions." Materials Science Forum 865 (August 2016): 6–11. http://dx.doi.org/10.4028/www.scientific.net/msf.865.6.
Повний текст джерелаАнотація:
One of the most important problem of concrete durability is increasing of waterproofing. Researches are devoted studying of cement mortars modified by carbon nanotubes, dispersed in plasticizers solutions. Were investigated physico-mechanical properties of cement paste, cement-sand mortar into which structure entered untreated carbon nanotubes (production of plant TM "Spetsmash" Kyiv, Ukraine) in various quantity. Were used as plasticizers in cement compositions additives substances of the various chemical nature – naphtaleneformaldehyde, melamineformaldehyde and polycarboxylate. Quantity of untreated nanotubes varied from 0,5%; 1,0% and to 1,5%. Concentration of additives was accepted taking into account recommendations of producers and made about 1% from the weight of cement. Were studied some technological processes of introduction untreated carbon nanotubes in cement system and is shown that the way of introduction of nanomodifiers has essential impact on strength characteristics of cementitious materials. Optimum decision introduction of untreated carbon nanotubes is using its in dispersion plasticizer of the working concentration prepared in an ultrasonic dispergator is established. Results of physico-mechanical tests of cement paste and cement-sand mortar showed positive influence at introduction of untreated carbon nanotubes as cement modifiers on strength characteristics of samples. Resalts is shown that the nanomodifier, used quantity about 1% in solution of lignosulfonate with polycarboxylate and melamineformaldehyde plasticizer has great impact on strength characteristics.
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Czarnecki, Lech, and Joanna Julia Sokołowska. "Optimization of Polymer-Cement Coating Composition Using Material Model." Key Engineering Materials 466 (January 2011): 191–99. http://dx.doi.org/10.4028/www.scientific.net/kem.466.191.
Повний текст джерелаАнотація:
The paper focuses on optimizing the elastic polymer-cement protection coating composition using material model. The material model consists of mathematical relations between composition and technical features demanded for protection, which are: flexibility, waterproofness and vapor permeability. The optimization that enabled obtaining the desirable values of features was proceeded by using statistical experimental design. Taking data from tests and choosing material variables, a material model based on quadratic functions was determined and in consequence three top rank compositions – each for a given feature – have been formulated. Evaluation of compositions was done using the desirability function approach. The individual desirability functions for the particular feature and the combined overall desirability function were treated as additional properties of the coating. Also, after defining the relation between desirability and composition, the overall desirability was enclosed in the material model as its generalization. High values of overall desirability confirmed the usefulness of compositions. The investigation proved that material models based on statistical methods are efficient tools for designing polymer-cement protective coatings.
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NETESA, M. I., A. V. KRASNYUK, A. M. NETESA, and N. A. NIKIFOROVA. "OPTIMIZATION OF CONCRETE COMPOSITIONS WITH SECONDARY INDUSTRIAL PRODUCTS." Bridges and tunnels: Theory, Research, Practice, no. 19 (July 27, 2021): 51–61. http://dx.doi.org/10.15802/bttrp2021/233874.
Повний текст джерелаАнотація:
Purpose. Analyze scientific publications on the existing problems of environmental pollution by secondary industrial products. Search for ways to solve these issues through the rational use of concrete in construction with additives of secondary industrial products, especially fine-grained ones. Determination of rational compositions of medium-strength concrete with the minimum required consumption of cement and filler from iron ore dressing wastes of mining and processing plants. Methodology. To achieve this goal, the experience of improving the structure and properties of concrete by introducing complex additives based on secondary industrial products into its composition is analyzed. The following materials were used for the research: Portland cement CEM 41.7 from Krivoy Rog; as a large aggregate – crushed granite with a maximum grain size of 20 mm; fine aggregate – river quartz sand; mineral additives – products of concentration of iron ores of the Southern Mining and Processing Plant. The experiment was carried out on certified equipment. Control specimens with a side of 10 cm were formed. The compressive strength of concrete was determined according to a standard procedure. Based on the results of the mathematical analysis, graphical dependences of the change in the optimized characteristics on the variable parameters – the consumption of cement, the products of concentration of iron ores and the plasticizer – were built. Findings. Based on the results of testing the samples, the calculation of mathematical models of the experiment was carried out and polynomials of the third degree were obtained for the optimized parameters – the average strength of the samples and the coefficient of efficiency of using cement. The following patterns can be distinguished. The strength of concrete depends to the greatest extent on the consumption of cement in the composition of the concrete mixture and increases significantly with an increase in its content within the studied limits. With an increase in the filler content in the studied range, the strength of concrete, and, accordingly, the coefficient of efficiency of using cement increases with a decrease in the content of cement in the composition of the concrete mixture. Originality. The studies carried out make it possible to determine the main regularities of increasing the efficiency of cement use when utilizing local secondary industrial products in concrete, namely, the introduction of iron ore dressing waste from mining and processing plants as a fine-grained additive in concrete. It was found that it is possible to obtain the required low concrete strength with a significantly lower cement consumption by ensuring a rational grain size composition of the concrete mixture components. Practical value. When designing concrete compositions with a high coefficient of cement utilization, it is necessary to use the obtained research results, providing cement savings and utilizing a significant amount of fine-grained secondary industrial products.
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Žibret, Lea, Katarina Šter, Maruša Borštnar, Mojca Loncnar, and Sabina Dolenec. "The Incorporation of Steel Slag into Belite-Sulfoaluminate Cement Clinkers." Applied Sciences 11, no. 4 (February 19, 2021): 1840. http://dx.doi.org/10.3390/app11041840.
Повний текст джерелаАнотація:
The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250 °C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such as belite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steel slags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250 °C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.
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Yakymechko, Yaroslav, and Vladyslav Voloshynets. "Expansive cements for the manufacture of the concrete protective bandages." Selected Scientific Papers - Journal of Civil Engineering 12, no. 2 (December 1, 2017): 147–54. http://dx.doi.org/10.1515/sspjce-2017-0031.
Повний текст джерелаАнотація:
Abstract One of the promising directions of the use of expansive cements is making the protective bandages for the maintenance of pipelines. Bandages expansive application of the compositions of the pipeline reinforce the damaged area and reduce stress due to compressive stress in the cylindrical area. Such requirements are best suited for expansive compositions obtained from portland cement and modified quicklime. The article presents the results of expansive cements based on quick lime in order to implement protective bandages pipelines.
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Taimasov, B. T., B. K. Sarsenbayev, T. M. Khudyakova, A. S. Kolesnikov, and N. N. Zhanikulov. "Development and Testing of Low-Energy-Intensive Technology of Receiving Sulphate-Resistant and Road Portlandcement." Eurasian Chemico-Technological Journal 19, no. 4 (December 29, 2017): 347. http://dx.doi.org/10.18321/ectj683.
Повний текст джерелаАнотація:
The article presents the obtaining results of clinkers of sulfate resistant and road cement during the production tests process. The usage of man-made wastes such as lead slag, coal mining waste as well as clay component and additives. X-ray, chemical analyzes of starting materials, clinkers and obtained cements were carried out. The regularities of charge compositions, saturation coefficient, modules, burning regimes on chemical and mineralogical composition and quality of clinkers and cements, improvement of rotary kiln operation, reduction of greenhouse gas emissions and fuel consumption are established. Various methods of analysis were used, calculations of raw mixtures composition were carried out according to the program "Shikhta" (designed to calculate the raw mix and the mineralogical composition of the clinker for the production of Portland cement. The program was developed in the V.G. Shukhov Belgorod State Technical University, Russia) and "Calculation of raw mixtures or CRM" (designed to calculate the raw mix of clinker. The program was developed in the M. Auezov South-Kazakhstan State University, Kazakhstan). The strength of factory and experimental cements was tested after 3, 7 and 28 days and after steaming.
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Demina, O. I. "Interaction of Portland cement hydration products with complex chemical additives containing fiberglass in moisture-proof cement compositions." Functional materials 24, no. 3 (September 29, 2017): 005–419. http://dx.doi.org/10.15407/fm24.03.415.
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Sujak, Agnieszka, Michał Pyzalski, Karol Durczak, Tomasz Brylewski, Paweł Murzyn, and Krzysztof Pilarski. "Studies on Cement Pastes Exposed to Water and Solutions of Biological Waste." Materials 15, no. 5 (March 4, 2022): 1931. http://dx.doi.org/10.3390/ma15051931.
Повний текст джерелаАнотація:
The paper presents studies on the early stages of biological corrosion of ordinary Portland cements (OPC) subjected to the reactive media from the agricultural industry. For ten months, cement pastes of CEM I type with various chemical compositions were exposed to pig slurry, and water was used as a reference. The phase composition and structure of hydrating cement pastes were characterized by X-ray diffraction (XRD), thermal analysis (DTA/TG/DTG/EGA), and infrared spectroscopy (FT-IR). The mechanical strength of the cement pastes was examined. A 10 to 16% decrease in the mechanical strength of the samples subjected to pig slurry was observed. The results indicated the presence of thaumasite (C3S·CO2·SO3·15H2O) as a biological corrosion product, likely formed by the reaction of cement components with living matter resulting from the presence of bacteria in pig slurry. Apart from thaumasite, portlandite (Ca(OH)2)—the product of hydration—as well as ettringite (C3A·3CaSO4·32H2O) were also observed. The study showed the increase in the calcium carbonate (CaCO3) phase. The occurrence of unreacted phases of cement clinker, i.e., dicalcium silicate (C2S) and tricalcium aluminate (C3A), in the samples was confirmed. The presence of thaumasite phase and the exposure condition-dependent disappearance of CSH phase (calcium silicate hydrate), resulting from the hydration of the cements, were demonstrated.
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Lan, Ming Zhang, Bin Feng Xiang, Jian Feng Wang, Xu Dong Zhao, and Xiao Ying Wang. "Effect of Anhydrite on the Early Hydration Performance of Rapid Setting and Hardening Belite Sulfoaluminate Cement." Materials Science Forum 898 (June 2017): 1990–95. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1990.
Повний текст джерелаАнотація:
In order to investigate the early hydration behavior of rapid setting and hardening belite sulfoaluminate cements, the methods of X-ray Diffraction, Scanning Electron Microscope, Compressive Strength test and Setting Times test were used to identify and quantify the hydration kinetics and microstructure of this new-found cements in China. The results showed that the main mineral compositions of high belite sulfoaluminate cement clinker included calcium sulfoaluminate (4CaO·3Al2O3·CaSO4), belite (2CaO·SiO2), ferrite phase, free gypsum and free lime. It was found that not only the setting time and compressive strength but also the composition of hydration products were influenced by anhydrite to some extent. Meanwhile, a mass of AFt and AFm generated along with the hydration process at different ages, overlapped, crossed and penetrated through calcium silicate hydrate gel and aluminum oxide to form a relatively dense structure which could contribute to the high strength of cement.
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Bassioni, Ghada. "GLOBAL WARMING AND CONSTRUCTION ASPECTS." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 2 (August 3, 2015): 78. http://dx.doi.org/10.17770/etr2009vol2.1013.
Повний текст джерелаАнотація:
The manufacture of cements with several main constituents is of particular importance with regard to reducing climatically relevant CO2 emissions in the cement industry. This ecological aspect is not the only argument in favor of Portland composite cements. They are also viable alternatives to Portland cement from the technical point of view. Substitution of ordinary Portland cement (CEM I) by Portland composite cements (CEM II) and (CEM III), which clearly possess different chemical and mineralogical compositions, results in changes of their reaction behavior with additives like superplasticizers. A common admixture to CEM I in that sense is limestone (industrial CaCO3). Its interaction with polycarboxylates is ignored and its inertness is taken for granted. This study provides a systematic approach in order to better understand the interaction of these polymeric superplasticizers with CaCO3 by adsorption and zeta potential measurements. The results give some fundamental understanding in how far the cement industry can reduce the production of cement clinker by replacing it with limestone as admixture and consequently the CO2-emission is reduced, which is of high political and environmental interest.
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Vasileva, Daria, Egor Protodiakonov, Anastasia Egorova, and Svetlana Antsupova. "Modifying admixtures to cement compositions produced from local raw materials." MATEC Web of Conferences 143 (2018): 02006. http://dx.doi.org/10.1051/matecconf/201814302006.
Повний текст джерелаАнотація:
Durability of hardened cement paste depends on chemical and mineralogical composition of Portland cement. The main factor for hardened cement paste is higher content of calcium aluminate and free calcium hydroxide, binding of which into water-insoluble compounds causes increase in resistance to water, frost and corrosion. The purpose of this research is to develop modifying admixtures to cement compositions based on local raw material - rock sand. Chemical and mineralogical properties of the source materials were studied using X-ray spectroscopy and X-ray diffraction analysis. Standard methods were used for defining physico-mechanical properties of sand and binder. Influence of the degree of mechanochemical activation of modifying admixture on the properties of binder and hardened cement paste made on its basis was studied. Research methods of scanning electron microscopy and spectral measurements were applied. The possibility of using admixture based on rock sand as a modifier was determined, its usage providing increase of strength, sulphate and frost resistance, which causes higher durability of cement concrete.