scholarly journals MODEL AND MECHANISM OF CARBON NANOTUBE STABILIZATION WITH PLASTICIZER BASED ON POLYCARBOXYLATE

Vestnik MGSU ◽  
2017 ◽  
pp. 724-732
Author(s):  
Svetlana Vasilevna Samchenko ◽  
Olga Viktorovna Zemskova ◽  
Irina Vasilevna Kozlova
Keyword(s):  
Portland Cement ◽  
High Viscosity ◽  
Matrix Composition ◽  
Cement Matrix ◽  
Cement Stone ◽  
Modern Theory ◽  
Ultrasonic Dispersion ◽  
Cement System ◽  
Electrical Layer ◽  
The Stability

The method for adding into the cement matrix composition the carbon nanotubes (CNTs) in the form of stabilized suspensions for their even allocation in its volume is observed in this article. The aim of the article is to study the aggregative and sedimentary stability of the CNTs suspensions in the presence of the plasticizer based on polycarboxylate under the ultrasonic effect, to determine the kinetic addictions of coagulation, to describe the suspension stabilization models and mechanisms according to the modern theory and to determine the possibility of using CNTs as suspensions for portland cement modification. The object of research is Portland cement, CNts and polycarboxylate-based plasticizer. Mechanism of stabilization of the CNT water suspension with polycarboxylate based plasticizer due to fixing plasticizer functional groups on the nanoparticle surface is proposed. The non-polar part of the plasticizer provides the formation of high-viscosity streak between the CNTs particles and the dispersion medium, and the polar part provides the formation of the double electrical layer (DEL), which supports the formation of the CNT micelle. The Model of the CNT micelle is described. It is established that the ultrasonic dispersion provides the stability of the CNTs suspensions for seven days and more. It is shown that when the stabilized polycarboxylate-based plasticizers of the CNT are introduced in the form of suspensions into the cement paste composition, they are evenly distributed in the volume of the cement system. This causes the production of cement stone with enhanced exploitative properties.

scholarly journals Model and mechanism of carbon nanotube stabilization with plasticizer

2018 ◽  
Vol 193 ◽  
pp. 03050 ◽  
Author(s):  
Svetlana Samchenko ◽  
Irina Kozlova ◽  
Оlga Zemskova
Keyword(s):  
Carbon Nanotube ◽  
Dispersion Medium ◽  
High Viscosity ◽  
Cement Stone ◽  
Ultrasonic Dispersion ◽  
Water Suspension ◽  
Nanoparticle Surface ◽  
Water Suspensions ◽  
Cement System ◽  
Electrical Layer

Mechanism of stabilization of carbon nanotube (CNT) water suspension with plasticizer based on sulfated naphthalene formaldehyde resins is proposed in this article. CNT stabilization is achieved at the expense of fixing plasticizer group on the nanoparticle surface. Nonpolar part of plasticizer provides the formation of high-viscosity streak between CNTs particles and dispersion medium, and polar part provides the formation of double electrical layer, that supports formation of CNT micelle. Model of carbon nanotube micelle is described. It is determined that the conducting of ultrasonic dispersion of CNTs water suspensions with plasticizer based on sulfated naphthalene formaldehyde resins provides stability of CNTs suspensions for 7 and more days. Optimal options of ultrasonic effect are identified. It is shown that CNT suspension stabilized with sulfated naphthalene formaldehyde evenly apportion in volume of cement system in conclusion of the adding them to composition of cement paste. This distribution helps with obtaining cement stone with high exploitative properties.

Model and Mechanism of Stabilization of Carbon Nanotubes with Placticizer on the Basis of Sulfonated Naphthalene Formaldehyde Resins

2018 ◽  
Vol 931 ◽  
pp. 481-488
Author(s):  
Svetlana V. Samchenko ◽  
Irina V. Kozlova ◽  
Olga V. Zemskova
Keyword(s):  
Aqueous Suspension ◽  
Double Electric Layer ◽  
High Viscosity ◽  
Polar Component ◽  
Cement Stone ◽  
Ultrasonic Dispersion ◽  
Aqueous Polymer ◽  
Nonpolar Component ◽  
Dispersion Media ◽  
The Stability

The entry presents studies of the effect of dispersion temperature on the deposition rate of CNTs in the presence of a plasticizer based on sulfonated naphthalene formaldehyde resins, on the dispersed composition of CNTs in aqueous and aqueous-polymer dispersion media and on the strength characteristics of samples with stabilized CNTs. It was established that the ultrasonic dispersion of aqueous suspensions of CNTs in the presence of a plasticizer based on sulfonated naphthalene formaldehyde resins at an ultrasonic vibration frequency of 44 kHz; dispersion temperature - 25 ± 2 °C; dispersion time - 10 - 30 minutes is capable of ensuring the stability of CNTs suspensions for 7 days or more. The mechanism of stabilization of aqueous suspension of CNTs by a plasticizer based on sulfonated naphthalene formaldehyde resins is presented. It has been established that the stabilization of CNTs is achieved by fixing the functional groups of the plasticizer on the surface of the nanoparticle, the nonpolar component of which ensures the formation of a high-viscosity interlayer between the CNTs particles and the dispersion medium, and the polar component is the formation of a double electric layer (DEL) that promotes the micellization of CNTs. As a result, the CNTs stabilized with sulfonaphthalene formaldehyde are evenly distributed in the volume of the cement system, causing the production of cement stone with enhanced performance properties.

scholarly journals Influence of optimal conditions of ultrasonic dispersion on the stability of suspensions of finely ground slags

2019 ◽  
Vol 265 ◽  
pp. 01017 ◽  
Author(s):  
Svetlana Samchenko ◽  
Irina Kozlova ◽  
Оlga Zemskova ◽  
Ekaterina Baskakova
Keyword(s):  
Aqueous Dispersion ◽  
Cement Composite ◽  
Cement Stone ◽  
Mechanical Mixing ◽  
Dispersion Parameters ◽  
Ultrasonic Dispersion ◽  
Sedimentation Stability ◽  
Granulated Blast Furnace Slag ◽  
The Stability ◽  
Furnace Slag

The preparation in the jet mill of finely ground slag (FGS) from the waste of metallurgical production granulated blast-furnace slag, the obtaining of slag suspensions, and the behavior of FGS particles in an aqueous dispersion medium are considered in the paper. It was found that FGS particles in the suspension form micelles of two types with negative (micelle 1) and positive (micelle 2) charges of FGS surface. To increase the aggregative and sedimentation stability of FGS particles in suspensions, studies were carried out using ultrasonic dispersion. The results of investigations on the detection of optimal dispersion parameters for slag suspensions are presented. It was found that in the absence of temperature control, the process of coagulation of slag particles is accelerated and aggregative and sedimentation stability of suspensions of FGS is reduced. The slag particles in the suspension form aggregates that lead to a deterioration of the strength characteristics of the cement stone using suspensions of FGS. Optimal parameters of ultrasonic dispersion of slag suspensions are established: the frequency of ultrasonic vibrations is equal to 44 kHz; the dispersion temperature is 25 ± 2 °C; the dispersion time is 15 min. It was found that the application of ultrasonic dispersion to slag suspensions with the observance of dispersion conditions can increase the aggregative and sedimentation stability of FGS suspension by 2-3 times in comparison with the mechanical mixing of suspensions. The strength of samples with suspensions of FGS prepared using UST under the recommended dispersing conditions increased by 19 to 39% in the first day; for 28 days of hardening - by 19 - 36%, which allows using slag suspensions in the production of cement composite materials and concretes based on them.

The Effect of Fine Dispersed Slag Component on the Slag Portland Cement Properties

2020 ◽  
Vol 1011 ◽  
pp. 103-108
Author(s):  
Irina Kozlova ◽  
Olga Zemskova ◽  
Vyacheslav Semenov
Keyword(s):  
Portland Cement ◽  
Structural Characteristics ◽  
Initial Period ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Stone ◽  
Ultrafine Grinding ◽  
Slag Component

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%.

scholarly journals INFLUENCE OF THE SCOPE ADDITION ON THE STRUCTURE FORMATION OF THE CEMENT STONE BY THE METHOD OF QUANTITATIVE X-RAY PHASE ANALYSIS

2019 ◽  
Vol 16 (4) ◽  
pp. 504-518
Author(s):  
I. L. Chulkova ◽  
I. A. Selivanov ◽  
V. D. Galdina
Keyword(s):  
Portland Cement ◽  
Structure Formation ◽  
Phase Analysis ◽  
Mineral Composition ◽  
Large Scale ◽  
Building Materials ◽  
Cement Matrix ◽  
Cement Stone ◽  
X Ray ◽  
Mineral Compositions

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.

Comparative Resistance of Concrete with Aggregates and Fillers of Different Composition

2021 ◽  
Vol 1017 ◽  
pp. 133-142
Author(s):  
Shark M. Rakhimbayev ◽  
Natalia M. Tolypina ◽  
Elena N. Khakhaleva ◽  
Daniil A. Tolypin
Keyword(s):  
Contact Layer ◽  
Cement Matrix ◽  
Cement Stone ◽  
Quartz Powder ◽  
Surface Layers ◽  
Electrokinetic Phenomena ◽  
Fine Grained ◽  
The Stability ◽  
Resistance Coefficients ◽  
Main Influence

The paper studies the influence of aggregates and fillers with negative and positive electrical surface properties on the corrosion resistance of concrete. The advantage of resistance of fine-grained concrete on marble sand in comparison with concrete on quartz sand, regardless of the type of aggressive environment, is established. At the same time, the stability of samples of powdered concrete with 10 and 30% of fine-grained filler changed little when replacing the quartz powder with marble one. It is shown that the resistance coefficients of powdered concrete samples with quartz filler (10%) do not differ from the resistance coefficients of samples of a similar composition with crushed marble filler, and with an increase in the dosage of the filler (30 %) slightly exceed. It was found that in powder concretes without aggregates, the contact layer between the cement matrix and the aggregate is absent, so the composition of the mineral powder plays a much smaller role in the corrosion processes of cement stone. The obtained results allowed establishing that electrokinetic phenomena play a secondary role, and the main influence on the stability of fine-grained concrete is the processes of pore colmation by chemical reactions, as well as the interaction of the surface layers of the aggregate with the cement matrix.

Effect of W/B ratios on pozzolanic reaction of biomass ashes in Portland cement matrix

2012 ◽  
Vol 34 (1) ◽  
pp. 94-100 ◽  
Author(s):  
V. Sata ◽  
J. Tangpagasit ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Cement Matrix ◽  
Biomass Ashes

scholarly journals Mineralogical stabilization of Ternesite in Belite Sulfo-Aluminate Clinker elaborated from limestone, shale and phosphogypsum

2018 ◽  
Vol 149 ◽  
pp. 01073
Author(s):  
K. Ben Addi ◽  
A. Diouri ◽  
N. Khachani ◽  
A. Boukhari
Keyword(s):  
Infrared Spectroscopy ◽  
Phosphoric Acid ◽  
Portland Cement ◽  
Stability Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

This paper investigates the mineralogical evolution of sulfoaluminate clinker elaborated from moroccan prime materials limestone, shale and phosphogypsum as a byproduct from phosphoric acid factories. The advantage of the production of this type of clinker is related to the low clinkerisation temperature which is known around 1250°C, and to less consumption quantity of limestone thus enabling less CO2 emissions during the decarbonation process compared to that of Portland cement. In this study we determine the stability conditions of belite sulfoaluminate clinker containing belite (C2S) ye’elimite (C4A3$) and ternesite (C5S2$). The hydration compounds of this clinker are also investigated. The monitoring of the synthesized and hydrated phases is performed by X-Ray Diffraction and Infrared spectroscopy. The results show the formation of ternesite at 800°C and the stabilization of clinker containing y’elminite, belite and ternesite at temperatures between 1100 and 1250°C.

scholarly journals A Study of the Potential Use of Red Mud to Obtain Compositions Based on Portland Cement

2020 ◽  
Author(s):  
Ekaterina Gerasimova ◽  
Elizaveta Gumirova
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Waste Product ◽  
Cement Stone ◽  
Mathematical Planning ◽  
Alumina Production ◽  
Mineral Additive ◽  
Composition Properties ◽  
Planning Of Experiments ◽  
Potential Use

The paper deals with the problem of utilization of red mud which is a waste product from alumina production using the Bayer method. The principal possible use for the red mud of JSC “Bogoslovsky aluminum plant” (Sverdlovsk region) for the compositions based on Portland cement is shown. It was found that the mud introduction accelerates beginning of the cement paste setting and thickens the paste reducing its mobility. It is concluded that the introduction of red mud up to 30 % is justified in terms of strength indicators. The work is carried out using mathematical planning of experiments. Keywords: red mud, Portland cement, active mineral additive, composition, properties, bauxite, chemical composition, cement stone strength, mathematical planning of experiments

scholarly journals Properties of cement composites based on limestone depending on their granulometric composition

Vestnik MGSU ◽  
2020 ◽  
pp. 999-1006
Author(s):  
Svetlana V. Samchenko ◽  
Olga V. Alexandrova ◽  
Anton Yu. Gurkin
Keyword(s):  
Composite Materials ◽  
Portland Cement ◽  
Granulometric Composition ◽  
Coarse Grained ◽  
Cement Matrix ◽  
Cement Composites ◽  
Construction Costs ◽  
Initial Strength ◽  
Fine Grained ◽  
Additional Formation

Introduction. The use of limestone in cement compositions as an additional cementing agent solves both environmental and economic problems, namely, reduction of construction costs. In this regard, the study of the properties of the granulometric composition and volumetric content of cement composites, containing limestone, becomes increasingly important. The mission of this research is to optimize the properties of composite materials containing Portland cement and limestone by changing the granulometric composition of flour limestone. Materials and methods. Limestone, having three different Blaine milling fineness values of 250, 300 and 450 m2/kg, was used; its content reached 10, 15, 25 and 35 %. Cement and sand mortars were applied for testing purposes. The influence of the granulometric composition of limestone on the workability and compressive strength of composite cement was determined. Results. The effect of limestone on the limit shear stress becomes more pronounced when the amount of limestone increases to 25 and 35 %. This is most noticeable for limestone with a high content of fine fractions of 5–20 µm. The use of finely milled limestone increases the initial strength of the composite material. By adding 10 and 15 % of such limestone we can increase the strength by 16–20 %, and supplementary 25–35 % of limestone increases strength by 5–8 %. Strength enhancement is due to the reactivity of limestone and formation of calcium hydrocarbon aluminate 3CaO∙Al2O3∙СаСО3∙12H2O, which promotes formation of the crystal framework of the cement matrix. Additional formation of crystalline hydrates in the initial coagulation structure deteriorates the mortar workability, but increases its strength. Conclusions. The use of coarse-grained limestone significantly improves mortar workability, while the use of fine-grained limestone increases its content without reducing its strength. The granulometric composition of ground limestone shall be as close as possible to the granulometric composition of cement for the properties of composite materials containing Portland cement and limestone to be optimized.

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