scholarly journals EFFECT OF ORGANIC AND FINE DISPERSER ADDITIONS ON RHEOLOGICAL PROPERTIES OF MINERAL SUSPENSIONS

2020 ◽  
Vol 18 (4) ◽  
pp. 469-476
Author(s):  
A.A. Guvalov ◽  
◽  
S.İ. S.İ. ◽  
Keyword(s):  
Rheological Properties ◽  
High Efficiency ◽  
High Strength ◽  
Limestone Powder ◽  
High Dispersion ◽  
Cement Stone ◽  
Organic Additives ◽  
Mineral Suspensions ◽  
Mineral Additives

In this study, the effect of mineral and organic additives on the properties of mineral suspensions was studied. Disperse mineral additives are used in cement systems to increase the amount of rheological matrix and ensure high fluidity. Due to the high dispersion of mineral additives, high-efficiency plasticizers were used to regulate the rheotechnological properties of cement-based mixtures. The effect of sulfonaphthalene-formaldehyde oligomer and polycarboxylate-based hyperplasticizers on the rheological properties of cement systems as a plasticizer was evaluated according to the methodology proposed by prof. V.I.Kalashnikov. Based on the results obtained, it was determined that limestone powder is more effective than other stone powders. As a result of the research, the optimal amounts of mineral additives and plasticizers were determined and the possibility of obtaining efficient, high-strength cement stone on their basis confirmed.

scholarly journals On the issue of expanding the base of mineral and complex additives for cement concrete

2019 ◽  
Vol 135 ◽  
pp. 01018
Author(s):  
Oleg Tarakanov ◽  
Elena Belyakova ◽  
Varvara Yurova
Keyword(s):  
Building Materials ◽  
High Efficiency ◽  
Materials Science ◽  
Raw Materials ◽  
Hydrate Formation ◽  
High Strength ◽  
Organic Additives ◽  
Cement Concrete ◽  
Concrete Production ◽  
Increased Strength

Modern materials science is characterized not only by the creation of high-strength building materials, but also by using a large number of raw materials and additives that improve the properties of concrete mixtures and concrete. The article considers the possibility of using both old and new generations of complex organomineral additives in concrete production. The nature of the effect of additives on the rheological behavior of cement systems and hydrate formation processes, as well as an assessment of the effect of mineral and organic additives on the composition of hydration products of cement systems, are revealed. Studies have shown that complex additives, which include hyper- and superplasticizers, lead to some slowdown in hydration and crystallization processes. The high efficiency of plasticizing additives helps to reduce water content, which in turn provides increased strength of cement concrete.

High-Quality Cement-Mineral Suspensions Using Stone Crushing Waste

2020 ◽  
Vol 992 ◽  
pp. 124-129
Author(s):  
E.A. Belyakova ◽  
R. Moskvin ◽  
V.S. Yurova
Keyword(s):  
Rheological Properties ◽  
Physicomechanical Properties ◽  
Cement Stone ◽  
Dispersed Phase ◽  
High Quality ◽  
Active Suspensions ◽  
Solid Ratio ◽  
Concrete Mix ◽  
Mineral Suspensions

The quality of concrete is determined by the physico-mechanical and rheological properties of the original components. Rheological properties depend on the amount and concentration of the rheological matrix. Cement-mineral matrices of modern high-quality concrete are rheologically active suspensions which allow to provide the necessary fluidity and mobility of the concrete mix, as well as the required strength of concrete. The multicomponent composition of the water-dispersed phase is represented by cement, stone flour and hyperplasticizer. The article presents the results of studies confirming the possibility of replacing finely ground quartz with other highly dispersed rocks, including stone-crushing waste. It was revealed that increasing in the concentration of the water-dispersed phase by 10% made it possible to reduce the water-solid ratio while maintaining the required mobility of the mixture, and in some cases improved the spreadability of the suspension by 3-13%. It was determined that the physicomechanical properties of reaction-powder concretes depend on the density and porosity of finely dispersed components to a greater degree.

scholarly journals FEATURES OF THE STRUCTURE OF NEW GENERATION CONCRETE WITH THE USAGE OF ARTIFICIALLY-PRODUCED MATERIALS

2018 ◽  
Vol 15 (4) ◽  
pp. 588-595 ◽  
Author(s):  
A. D. Tolstoy ◽  
V. S. Lesovik ◽  
A. S. Milkina
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Raw Materials ◽  
Experimental Studies ◽  
Construction Materials ◽  
High Strength ◽  
Standard Test ◽  
Cement Stone ◽  
Organic Additives ◽  
Test Procedures

Introduction. The important national economic task is to provide the modern construction industry with high-strength and effective materials made using new technological approaches and artificiallyproduced materials. These materials differ from the usual one by high content of cement stone, smaller grain size, multicomponent composition, increased specific surface of the filler. Therefore, the research of such problem would be always relevant according to the constant growth of requirements for the building materials and structures quality.Materials and methods. Experimental studies were conducted in the laboratories of the Department of Construction Materials, Products and Structures. The literary sources’ analysis was made in the scientific and technical library of the Belgorod State Technological University named after V. G. Shukhov. At the same time, standard test procedures and the provisions of the operating instructions for individual devices and equipment were used in the research.Discussion and conclusions. As a result, the models of structure formation in high-strength hardening compositions, in which the principle of structure optimization consisting in creation of the high degree ordering of its constituent elements and tumors, as well as in increasing the adhesion of cement stone particles, are implemented. In addition, the usage of artificially-produced materials and organic additives produces the possibility of reducing the consumption of raw materials and consumption of energy and resources. The mechanism and principles of structure formation management are intensively studied and would be explained later on the basis of synergetic concepts.

scholarly journals COMPREHENSIVE MODIFICATION OF GELS POLYACRYLAMIDE

2016 ◽  
pp. 16-25
Author(s):  
Tatiana Shevchenko ◽  
Tatiana Shevchenko ◽  
Yulia Ustinova ◽  
Yulia Ustinova
Keyword(s):  
Amino Acids ◽  
Rheological Properties ◽  
High Efficiency ◽  
Chemical Nature ◽  
High Strength ◽  
Strain Rates ◽  
Physical Methods ◽  
Initial Yield Stress ◽  
Chemical Factors ◽  
The Impact

For successful use of flocculants it is necessary to give them new features artificially, among which the most important are rheological properties - shear stress at different strain rates. They can be changed while using methods of chemical and physical modifications and the most promising among them are physical methods of modification. Comparative rheological properties of polyacrylamides aqueous solutions without and with modification of the bifunctional connections of different chemical nature (glycols, amino acids) were given. The strengthening of the modification effect was achieved by the additional impact of physic-chemical factors: ultrasonic and microwaves with a frequency of 2.45 GHz for 10 s with a power of 700 watts. The thorough analysis of the rheological studies data for each flocculant was made. With modifying PG initial yield stress (Θf) increased 1.1-1.5 times, while with the modification by glycine, this value changed to 1.1-1.7 times. The optimal concentration of PE to obtain gels with high strength comprises: a modified GHG - 1.0%, modified by glycine with the influence of ULTRASONIC - 1.0% modified by glycine - 0.7%, modified by glycine with the impact of MVO - 0.3%, indicating high efficiency of the use of glycine and MVO. It was found out that Θf in the case of using PG - 1.5 times higher than that of the original (if sopt = 1.0%); when using the glycine - to 1.7 (sopt = 0.7%) higher than that of the original; in the using of glycine together with ULTRASONIC - in 1.5 times (when sopt = 0.1%) higher than that of the original, when using glycine in conjunction with MVO - in 1.9 times (if sopt = 0.3%).

High-Strength High-Efficiency Particulate Air Filters for Nuclear Applications

1990 ◽  
Vol 92 (1) ◽  
pp. 11-29
Author(s):  
Volker Rüdinger ◽  
Craig I. Ricketts ◽  
Jürgen G. Wilhelm
Keyword(s):  
High Efficiency ◽  
High Strength ◽  
Air Filters ◽  
Nuclear Applications

scholarly journals Development of Self-Sensing Textile Strengthening System Based on High-Strength Carbon Fiber

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2062
Author(s):  
Marcin Górski ◽  
Rafał Krzywoń ◽  
Magdalena Borodeńko
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
High Efficiency ◽  
High Strength ◽  
Strain Gauges ◽  
Building Structures ◽  
Climatic Chamber ◽  
Daily Cycle ◽  
Temperature Changes ◽  
Temperature And Humidity

The monitoring of structures is one of the most difficult challenges of engineering in the 21st century. As a result of changes in conditions of use, as well as design errors, many building structures require strengthening. This article presents research on the development of an externally strengthening carbon-fiber textile with a self-sensing option, which is an idea is based on the pattern of resistive strain gauges, where thread is presented in the form of zig-zagging parallel lines. The first laboratory tests showed the system’s high efficiency in the measurement of strains, but also revealed its sensitivity to environmental conditions. This article also presents studies on the influence of temperature and humidity on the measurement, and to separate the two effects, resistance changes were tested on unloaded concrete and wooden samples. The models were then placed in a climatic chamber, and the daily cycle of temperature and humidity changes was simulated. The research results confirmed preliminary observations of resistivity growths along with temperature. This effect is more visible on concrete samples, presumably due to its greater amount of natural humidity. The strain measurement with carbon fibers is very sensitive to temperature changes, and applications of this method in practice require compensation.

Comparative Study of Metakaolin and Zeolite Tuff Influence on Properties of High-Strength Concrete

2022 ◽  
Author(s):  
Leonid I. Dvorkin ◽  
Vadim Zhitkovsky ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi
Keyword(s):  
High Strength ◽  
Economic Feasibility ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
High Dispersion ◽  
High Dispersity ◽  
Energy Consuming ◽  
Effective Use ◽  
Pozzolanic Properties ◽  
Zeolite Tuff

Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances to resources and energy consuming mineral admixtures like metakaolin and silica fume. The deposits of zeolites are developed in Transcarpathia (Ukraine), USA, Japan, New Zealand, Iceland and other countries. It is known that zeolite tuffs exhibit pozzolanic properties and are capable to substitution reactions with calcium hydroxide.However, the high dispersion of zeolite rocks leads to a significant increase in the water consumption of concrete. Simultaneous introduction of zeolite tuffs with superplasticizers, which significantly reduce the water content, creates the preconditions for their effective use in high-strength concrete.Along with dehydrated (calcined) zeolite, natural (non-calcined) zeolite expresses itself as an effective mineral admixture of concrete. When using non-calcined zeolite, the effect of increasing in compressive strength at the age of 3 and 7 days is close to the effect obtained when using dehydrated zeolite: 8-10% and 10- 12%, respectively, and 28 days the strength growth is 13-22%. The use of non-calcined zeolite has a significant economic feasibility, so it certainly deserves attention. There were compared the effect of zeolite to metakaolinThe results of the research indicate that the use of composite admixtures, consisted of calcined (non-calcined) zeolite tuff of high dispersity and superplasticizer of naphthalene formaldehyde type, allows to obtain concretes classes C50…C65.

scholarly journals Effect of Mineral Admixtures on the Sulfate Resistance of High-Strength Piles Mortar

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3500
Author(s):  
Yanyan Hu ◽  
Linlin Ma ◽  
Tingshu He
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Strength ◽  
Mineral Admixtures ◽  
Quartz Powder ◽  
Sulfate Resistance ◽  
Powder Samples ◽  
Mineral Additives ◽  
Furnace Slag

Pre-stressed high-strength concrete piles (PHCP) are widely used in the building industry in China. The main aim of our research was to investigate the utilization of quartz powder, fly ash, and blast furnace slag as mineral additives to prepare PHCP mortar. The samples were prepared using steam and autoclaving steaming. The influence of minerals on the sulfate resistance of mortar was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. The results showed that when compared to single doped quartz powder samples, samples prepared using fly ash or blast furnace slag improved the sulfate resistance of the PHCP mortar. Furthermore, the resistance to sulfate attack of samples with dual doped quartz powder, fly ash, and blast furnace slag also improved. MIP tests showed that mineral additives can change the pore size distribution after autoclave curing. However, the number of aching holes increased after mixing with 20% quartz powder and caused a decrease in the sulfate resistance.

scholarly journals Transverse Deformations and Structural Phenomenon as Indicators of Steel Fibred High-Strength Concrete Nonlinear Behavior

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Iakov Iskhakov ◽  
Yuri Ribakov
Keyword(s):  
High Strength Concrete ◽  
High Efficiency ◽  
Limit State ◽  
Nonlinear Behavior ◽  
High Strength ◽  
Steel Fibers ◽  
Ultimate Limit State ◽  
Strength Concrete ◽  
Brittle Behavior ◽  
Ductile Behavior

As known, high-strength compressed concrete elements have brittle behavior, and elastic-plastic deformations do not appear practically up to their ultimate limit state (ULS). This problem is solved in modern practice by adding fibers that allow development of nonlinear deformations in such elements. As a rule, are applied steel fibers that proved high efficiency and contribute ductile behavior of compressed high-strength concrete (HSC) elements as well as the desired effect at long-term loading (for other types of fibers, the second problem is still not enough investigated). However, accurate prediction of the ULS for abovementioned compression elements is still very important and current. With this aim, it is proposed to use transverse deformations in HSC to analyze compression elements' behavior at stages close to ultimate. It is shown that, until the appearance of nonlinear transverse deformations (cracks formation), these deformations are about 5-6 times lower than the longitudinal ones. When cracks appear, the tensile stress-strain relationship in the transverse direction becomes nonlinear. This fact enables to predict that the longitudinal deformations approach the ultimate value. Laboratory tests were carried out on 21 cylindrical HSC specimens with various steel fibers content (0, 20, 30, 40, and 60 kg/m3). As a result, dependences of transverse deformations on longitudinal ones were obtained. These dependences previously proposed by the authors’ concept of the structural phenomenon allow proper estimation of the compressed HSC state up to failure. Good agreement between experimental and theoretical results forms a basis for further development of modern steel fibered HSC theory and first of all nonlinear behavior of HSC.

scholarly journals Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4376
Author(s):  
Yanqi Hu ◽  
Zekan He ◽  
Haijun Xuan
Keyword(s):  
Carbon Fibers ◽  
High Efficiency ◽  
Laminated Composites ◽  
Impact Resistance ◽  
Three Dimensional ◽  
High Strength ◽  
Woven Composites ◽  
Failure Behavior ◽  
Bismaleimide Resin ◽  
Modeling Strategy

Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance research on three-dimensional orthogonal woven composites consisting of carbon fibers/bismaleimide resin (BMI). A series of impact tests were conducted using the gas gun technique with the impacted target of 150 mm × 150 mm × 8 mm (length × width × thickness) and the cylindrical titanium projectile. The projectile velocity ranged from 180 m/s to 280 m/s, generating different results from rebound to perforation. This paper also presents a multiscale modeling strategy to investigate the damage and failure behavior of three-dimensional woven composites. The microscale and mesoscale are identified to consider the fiber/matrix scale and the tow architecture scale respectively. The macroscale model was effective with homogenized feature. Then a combined meso-macroscale model was developed with the interface definitions for component analysis in the explicit dynamic software LS-DYNA. The presented results showed reliable interface connection and can be used to study localized composites damage at a relatively high efficiency.

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