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Über dieses Buch

This book gathers the latest advances, innovations, and applications in the field of building design and construction, as presented by researchers and engineers at the International Conference BUILDINTECH BIT 2020, Innovations and Technologies in Construction, held in Belgorod, Russia, on October 8-9, 2020. It covers highly diverse topics, including building materials, industrial and civil construction, structural mechanics and theory of structures, computational methods and IT in construction, organization and technologies of construction production. The contributions, which were selected by means of a rigorous international peer-review process, highlight numerous exciting ideas that will spur novel research directions and foster multidisciplinary collaborations.

Inhaltsverzeichnis

Frontmatter

Statistical Analysis of the Frequency of Damage Accumulation in the Structure of Epoxy Composites Under Tensile Loads

Statistical analysis of the frequency of damage accumulation in the structure of epoxy polymer samples subjected to tensile loads was performed. Samples of polymers produced on the basis of epoxy modified binder Etal-247 cured with hardener Etal-45M, which is a mixture of aromatic and aliphatic di- or polyamines, were chosen as the object of research. The main criterion for determining the coordinates of “critical” points was the results obtained using the author’s method for estimating changes in the fractality index based on the use of the least coverage method. The values of tensile stresses and relative elongations registered with high reading frequency (0.01 s) were used as input data. The levels of “critical” states corresponded to the values of fractality indices less than 0.5. The levels of accumulated damage were revealed with the excess leading to sample destruction. It has been established that in order to obtain the most objective results in the study of the damage accumulation kinetics, it is advisable to analyze not a single “most representative” sample, but a number of samples of the studied structure.

T. A. Nizina, D. R. Nizin, N. S. Kanaeva

Mixed Binders with the Use of Volcanic Ash

The most promising direction in modern science and construction is the creation of new effective mixed binders with specified properties. In recent years, there has been a significant increase in interest in the use of natural and technogenic products as components of mixed binders, the use of which is promising and relevant. This article presents the results of research on the production of mixed binders using volcanic ash from the Kenzhensky Deposit of the Kabardino-Balkar Republic in a vibrating mill, and the features of their grinding are established. Mixed binders were obtained at different ratios of cement and volcanic ash. The features of grinding and microstructure processes are studied, and the technological and physical and mechanical properties of the obtained binders are determined. The combined activation of mixed binders based on cement and volcanic ash in amount of 10% increases the compressive strength by 23%, and when using 20% of ash increases the strength by 22%, with significant savings of Portland cement up to 20%. The results obtained indicate the influence of the granulometric composition of mineral filler and cement in mixed binders on the formation of their physical and mechanical indicators.

L. H. Zagorodnyuk, A. E. Mestnikov, D. S. Makhortov, Akhmed Akhmed Anis Akhmed

The Effect of Titanium Dioxide Sol Stabilizer on the Properties of Photocatalytic Composite Material

This study aimed to establish the effect of a hydrolysis catalyst and a stabilizer of a hydrated titanium dioxide sol, such as nitric acid, in the synthesis of the photocatalytic composite material (PCM) of the SiO2–TiO2 system on its physicochemical characteristics. It was found that among the analyzed two types of photocatalytic composite materials (with and without nitric acid) having a similar chemical composition it is preferable to use material without nitric acid as a photocatalytic additive. It has higher photocatalytic activity, as it contains a significant amount of anatase-modified titanium dioxide with a developed surface, including nanosized particles. In the composition of PCM (without nitric acid), the presence of agglomerates of spherical particles of titanium dioxide is noted. In this case, the surface of diatomite is uniformly coated with titanium compounds. The structure of titanium-containing neoplasms in the composition of FCMN (with nitric acid) is significantly different. It has the form of a film deposited on diatomite particles. As a result, the surface of the PCMN is much less developed.

M. V. Antonenko, Y. N. Ogurtsova, V. V. Strokova, E. N. Gubareva

Influence of Clinker Microstructure on Grinding Efficiency in the Presence of Grinding Intensifiers

Grinding processes in cement production technology are quite energy-intensive. The mechanism of action of surfactants on the course of the clinker grinding process has not been fully studied. According to the theory of P.A. Rebinder, surfactants change the mechanical properties of solids in the process of dispersion of materials. At the same time, the destruction of clinker grains must comply with the basic laws of physical and chemical mechanics of destruction of polymineral rocks. The results of the study of the grinding capacity of clinker grains show that their mechanical properties are determined by the size, shape, composition, spatial orientation and physical properties of the main phases. The paper presents the results of a study of the influence of the microstructure of Portland cement clinker on the efficiency of grinding in the presence of triethanolamine. It is shown that the grinding kinetics depends primarily on the characteristics of the clinker microstructure. The presence of surfactants accelerates grinding at the last stage by reducing the agglomeration forces.

L. D. Shahova, L. S. Schelokova, E. S. Chernositova

Obtaining High-Quality Expanded Porous Gravel Based on Low-Expanding Stone-Like Clay

The present paper deals with the obtaining of high-quality keramzit aggregate on the base of low-expanding stone-like hydromicaceous clay. The developed technology allows to widen raw stuff base of producing aggregates for lightweight concretes and to improve their physico-mechanical properties.It has been revealed from investigations that the composition of stone-like clay does not contain sufficient quantity of gas-generating substances which are the main factor of developed pore formation on expansion. For this reason the influence of various pore-forming additives on the expansibility of the said clay was studied. Simutaneously investigations into expansibility of stone-like low-expanding clay depending on expansion condition were being performed. It has been found out that clay expansibility and physico-mechanical properties of the obtained aggregate depend on preliminary thermal treatment temperature, temperature and duration of expansion. Using porous gravel of density brand 300–700, dense sand and plasticizing additives, lightweight concrete of 850–1800 kg/m3 in density and strength of 3.4–42.0 MPa has been produced and using porous gravel, dense sand without plasticizing additives lightweight concrete with density of 1150–1170 kg/m3 and strength of 10.0–35.0 MPa has been obtained.

H. N. Mammadov, A. A. Guvalov

Stress-Strain State of Normal Sections of Precast-Monolithic Reinforced Concrete Beams

The paper is devoted to theoretical and experimental studies of the stress-strain state of normal sections of precast-monolithic reinforced concrete beams. It is noted that at present there is a significant increase in interest in methods for calculating reinforced concrete structures taking into account nonlinear diagrams of concrete deformation. This is due both to the occurrence of reliable experimental data on the parameters of such a diagram, and to the widespread use of computational techniques. At the same time, despite the fact that numerous studies were conducted on studying the force resistance of reinforced concrete bending elements of composite sections and the development of methods of their calculation considerable success has been achieved, the tasks associated with the analytical evaluation of the stress-strain state of normal sections of precast-monolithic concrete beams have been remained unsolved. In this regard, a refined calculation method has been developed that allows determining the parameters of the stress-strain state at all stages of loading. For its justification, special experimental studies of samples of precast-monolithic reinforced concrete beams were conducted. The results of control tests are described and their brief analysis is made. Numerical studies on the convergence of theoretical and experimental data were carried out. The accuracy of the developed calculation method is estimated.

A. A. Kryuchkov, N. V. Frolov, G. A. Smolyago

Low-Carbon Principles of Eco-Efficient Construction Development

One of the most exigent problems of the modern construction industry is lack of sustainability. This ultimate issue of the construction industry is exacerbated by the absence of an effective and transparent regulation tool, which provides clear understanding of necessity of designing more ecologically conscious and low-carbon construction solutions. GHG emissions in construction industry cover a significant part of industrial GHG emissions and are expected to consistently increase. Therefore, the conversion of the subject and results of the study to algorithms, tools and institute for managing and regulating carbon impact in the process of creating civil construction objects from the point of effective management of green construction and extended environmental responsibility of the developer is justified, promising and contains significant research potential. The key aspects of the proposed eco-friendly comparative analysis based on alternative design concepts of building realization of given consumer characteristics and functional purpose, performed in traditional and with using of the green structural and technological solutions are presented in the article.

I. P. Avilova, A. E. Naumov, M. O. Krutilova, D. D. Dakhova

Shungite Waste – An Effective Mineral Additive for Concrete Modification

This article is devoted to the research of shungite waste generated in the process of extraction and technological operations. Despite the rich raw material base of the mining industry, there is no market for domestic modifying additives based on local raw materials. Shungite waste expands the range of mineral additives and provides qualitatively new properties to concrete and reinforced concrete products and structures.The paper is also considers the research of shungite waste as a modifying mineral additive of concrete. Its influence on the main characteristics of concrete is studied and the features of processes occurring in the hardening silicate system “cement - dispersed shungite particles” are shown, which provide an increase in the strength of concrete and reduce the duration of its heat and humidity treatment.The features of dispersed particles of a mineral additive from shungite waste in hardening silicate systems are shown, which consist in the fact that the surface of the mineral filler particles is subject to hydration, which contributes to the production of concrete and mortar with improved physical and mechanical characteristics. Amorphism of SiO2 particles in the mineral filler creates foci of formation of crystals of hydroaluminates and calcium hydrosilicates.

A. S. Estemesova, Z. N. Altaeva, Zh. T. Aimenov

Concrete Chemicalization for Digital Printing: Control of Rheology and Structure Formation

The stages of evolution of rheological properties and structure formation of concrete in digital printing conditions with layer-by-layer application of material and in the absence of formwork are considered. A solution to the problems of each stage of the evolution of rheology is proposed by concrete chemicalization, which is a fine-grained composite based on two active substances: a mineral binder and a polymer binder. The chemical additives present in concrete are represented by a complex of phloroglucinfurfural oligomers and polymer molecules of polyvinyl alcohol. It was found that the phloroglucinfurfural super plasticizer not only reduces the maximum dynamic shear stress, but also increases the area of the hysteresis loop, which characterizes the structure of the system and the speed of its recovery after destruction. It is proved that polymer molecules lead to an increase in the elastic-plastic strength of the layer. The interaction between the system components of both the dispersed phase (polyvinyl acetate, cement, sand) and the dispersion medium (phloroglucinfurfural oligomers, polyvinyl alcohol molecules) does not lead to undesirable side effects; on the contrary, there is a positive synergy effect when additives act on the rheology and structure formation of concrete.

V. A. Poluektova, N. A. Shapovalov

Stabilization of the Clay Soil of the Increased Humidity for Road Construction

In the work, the influence of stabilizing additive «Baustab» (produced by the Scientific and Production Enterprise «Plant of Innovative Industrial Equipment») on the change in humidity, water-holding capacity of soil with increased humidity was studied. We also studied changes in the maximum density and optimal moisture content of the modified soil using the example of light sandy loam. It has been established that the use of the additive slightly affects the change in soil moisture over time. Despite this, «Baustab» - added soil becomes denser, more viscous, partially aggregated, and no water separation is observed. A study of the water retention capacity of the percentage of stabilizing additives «Baustab» showed an increase in this indicator compared with soil without additives in the range from 3 to 7%. In addition, the use of additives in the soil composition increased its compaction and mobility even at low humidity of the modified soil. The effect of water on compaction of modified soil is also negligible. Such soil is likely to be subject to minimal subsidence and loss of strength characteristics in the autumn-spring period.

A. I. Trautvain, A. E. Akimov, V. A. Grichanikov

Progressive Destruction of Frame Buildings Made of Monolithic Reinforced Concrete

The design of multi-storey buildings is currently carried out with mandatory verification of their progressive destruction. Progressive destruction is the process of rapid sequential destruction of load-bearing structures due to the destruction of any element of the building or part of it. Different factors can be the causes of local destruction: an explosion of household gas, terrorist acts, the impact of vehicles on the supporting structures of the building, the impact of wind loads that exceed the amount accepted in the project, and so on. The article investigates possible scenarios for the occurrence of a progressive destruction due to a car hitting one of the columns along the perimeter of a multi-storey frame building. Options were considered for a car hitting a row column located in the middle of the building, as well as a car hitting one of the corner columns. It was found that the impact of a car hitting an ordinary column leads to its destruction, as well as the destruction of the building ceiling above the first floor. The most dangerous option is the car hitting the corner column. A hit to the corner column causes the corner of the building to collapse globally.

T. K. Ksenofontova

Increasing the Stability of the Polyimide Radiation-Protective Composite to the Effects of Atomic Oxygen

The paper presents data on increasing the resistance to atomic oxygen of a polymer composite based on polyimide and tungsten oxide WO2 by adding crystalline silicon. As an additive to the composite, finely dispersed crystalline silicon of the KR-00 grade 40 μm with a specific surface area of 5 m2/g was used. Tests simulating the effect of atomic oxygen on composites in space were carried out by treating polyimide composites with oxygen plasma. The energy of atoms and oxygen molecules reached 35 eV. Composites of optimal composition with a content of 65 wt% WO2 were tested. The data on the mass loss of composites after treatment with oxygen plasma are presented, and the microstructure of the surface of the composites is studied. The introduction of an additive of crystalline silicon in an amount of 1 wt% allows reducing the mass loss of the composite under the influence of an oxygen plasma flow by 31.6%.

N. I. Cherkashina, Z. V. Pavlenko, N. V. Kashibadze

Reactivity of the Clay Component of Rocks at the Incomplete Stage of Mineral Formation to Lime During Autoclave Processing

High reactivity to lime in the conditions of autoclave processing of clay loam component of the Lebedinsky field, morillonite-hydro micaceous-quartz clay and opoka clay, which belong to the rocks of the incomplete stage of mineral formation. The peculiarity of these deposits is the presence of thermodynamically unstable compounds, such as hydro mica, mixed-layer formations, and x-ray amorphous phase formed as a result of processes of disintegration of the crystal structure of the source minerals due to weathering processes. Such rocks make up the majority of clay deposits and are widely distributed on the territory of the Russian Federation and in many states of the world. According to the results of these kinetic studies the features of phase formation in the system “CaO–SiO2–Al2O3–H2O” on the basis of clay component of rocks at the incomplete stage of mineral formation are found out, consisting in the intensification of the synthesis of gel-like and crystalline cementing compounds, such as low-base and high-base calcium hydro silicates, alumina-containing tobermorite and hydrogranates. It is shown that due to the polymineral composition of the clay component, the synthesis of different new formations proceeds in different time periods, which reduces the number of microdefects and accelerates the formation of a cementing substance of a rational microstructure. The clay component of rocks at the incomplete stage of mineral formation can be used as a component of the raw material mixture to produce effective silicate materials using energy-saving technology.

A. N. Volodchenko, V. V. Nelyubova

Examination of the Safety of the Centrifuge Site of a Sugar Factory in the Belgorod Region in Order to Assess the Technical Condition of Structures

The structure integrity is affected equally adversely by both the defects revealed as a result of builders and designers’ negligence and those that appeared during operation, even to a greater extent. During the survey violations of the integrity of bearing and enclosing structures are detected, which can lead to emergency situations. Unfortunately, not all types of damage can be detected with the naked eye. The detected defects make it possible to predict the behavior of structures during their operation and allow determining the suitability of the entire building structure for further use. The object of the survey is a centrifuge platform at the sugar factory of the Belgorod region. The non-implementation of previously recommended measures and the ongoing process of corrosion and deformation destruction of building structures caused doubt about the safety of certain structural components of the platform, which ultimately led to the conduct of these surveys.

I. R. Serykh, E. V. Chernysheva, A. N. Degtyar

Tape System for Damping Vibrations of Mesh Domes with a Central Mount for Seismic Impacts

This article describes a tape system for damping vibrations of mesh domes with central reference points during seismic impacts. Based on the forms of the locator’s own vibrations at low frequencies, the effective location of the vibration dampener was selected. A program for dynamic calculation of dome-type mechanical systems based on the method of central differences has been developed. A mathematical model of a mechanical system with a vibration dampener based on the differential equation of vibrations taking into account the tension forces of the belts and the resistance to unwinding of the belts in inertial coils. A series of numerical experiments has been carried out, which has shown the high efficiency of the tape vibration damping system. With this arrangement of the dampener and the accepted model of vibration damping, the most significant parameter of damping is the force of the beginning of unwinding of the coils. Analysis of the graphs presented above shows that it is the parameter N that provides the greatest damping effect. In this example, for a locator with an outer ring radius r = 10 m, the maximum decrease in the oscillation amplitude (by 40–50%) gives the parameter value N = 900 N at b = 750 kg/s.

A. I. Shein, A. V. Chumanov

Eco-Cement for 3D-Additive Technologies in Construction

Modern construction technologies develop mainly through the use of new materials and minor changes in the construction of buildings. This paper presents the advantages of using 3D-additive technologies in construction: increasing the speed of construction, cutting production costs, energy efficiency, sustainable use of secondary construction resources and advanced materials, great variety of space-planning and architectural solutions. This line of research confirms the relevance of the selected problem. Requirements to composite binders with the predefined set of properties and structural and functional organization are specified. The criteria of selecting the composites’ formulas for using them in 3D printing technologies are formulated. The findings of prism strength and energy-efficiency studies of composite binders on the basis of eco-cement are presented. To meet a number of technical, technological and economic requirements to a concrete on the basis of composite binders for 3D-additive technologies in construction, the application of a set of modifying additives and eco-cement is needed.

V. S. Lesovik, A. N. Babaevsky, E. S. Glagolev, A. A. Sheremet

Research on the Possibility of Using Volcanic Sand of Kamchatka as a Component of a Composite Binder

Composite binders with the use of raw materials of various genesis as a siliceous component are a promising material, as their application allows solving a number of significant problems, in particular, to expand the raw material base for regions where there is no natural raw material; to reduce the load on the environment by using raw materials stored in heaps and reducing the clinker component; and to obtain materials with unique properties. The results of research aimed at studying the possibility of using the volcanic sand of Kamchatka from the Klyuchevskoy volcano (the lower waterfall of the Krutenkaya River) as a component of composite binders are presented. Based on the fact that the main obstacle to the extensive application of composite binders are significant energy costs associated with its production by grinding, the possibility of using not only the sand itself, but also its silt fraction was considered. For this purpose, the material composition, morphology and granulometry of volcanic raw materials and its silt fraction were studied. Based on the obtained results, conclusions are made about the feasibility of using the studied raw materials as a component of composite binders and the possibility of additional reduction of energy consumption for their production due to the use of a silt fraction.

N. I. Alfimova, I. M. Shurakov, M. S. Ageeva, N. I. Kozhukhova

Innovative Approaches to Residential Development Using Large-Panel Elements

The article is devoted to the application of innovative trends in residential development using large-panel elements. The relevance of this study is determined by the increasing requirements for the efficiency of large-panel housing construction. The main innovations related to the application of monolithic joint; hinge joints of reinforced concrete elements without using welded joints; space-planning solutions of sections of large-panel houses with longitudinal bearing L-shaped walls; structural layout of panel housing with the first floor frame construction; combinations of large-panel elements and various acoustic and thermal insulation materials; 3D printers for optimization of factory processes for the manufacture of printed non-standard structural elements; BIM-technologies for monitoring the technical condition and quality control of seams in large-panel buildings. The article presents an analysis of advantages of using innovative approaches to development of large-panel reinforced concrete construction of residential buildings and also provides their brief overview. The article offers an original integrative approach to increase the efficiency of large-panel housing construction, taking into account the conditions for applying a set of innovative achievements in the field of construction, which will allow to achieve the goals of providing the population with affordable and comfortable housing.

R. G. Abakumov, M. A. Shchenyatskaya, I. V. Ursu, M. I. Oberemok

The Aspect of Color Optimization of the Mineral Repair Mixture for the Brickwork Restoration

The paper presents the testing of the optimization method of the composition of repair compound to a historic brick to compensate its losses, consisting in a step-by-step selection of mineral raw materials which ensure color identity and affinity of structures. Ceramic filled bricks of 1859 and 1786 were used as samples. Their color characteristics in the CIE L*a*b* system are studied. It was found that the cement-sand repair compositions prepared at the first stage of the study with the addition of modern bricks in the form of crumbs and powder do not correspond in their color characteristics to historical bricks. To eliminate the color difference, in the second stage various experimental techniques were used to increase the values of chromatic components a* and b* (increasing the fineness of fillers grinding, removing cement milk from the surface of samples of repair compositions), and various pigments were introduced into the repair mixture. As a result of this adjustment, it was possible to obtain repair mix compositions that correspond to the ranges of historical bricks in all three color characteristics.

V. E. Danilov, D. V. Ershkov, A. M. Ayzenshtadt

Concrete and Fiber-Reinforced Concrete in a Cage Made of Polymers Reinforced with Fibers

Experimental studies have shown that in steel pipes filled with concrete, there is a rather weak coupling between the concrete and the cage. This is due to the significant difference in the Poisson ratio of steel and concrete, which causes the concrete to separate from the pipe when both materials experience longitudinal deformation, as well as the fact that the shrinkage of the concrete leads to delamination at the contact boundary of the two materials under any loading. As a result, pipe-concrete elements may fail due to steel yield or concrete crushing. This disadvantage is overcome by the use of polymers reinforced with fibers (FRP), that is, the device of a fiberglass or carbon-plastic cage. Increasing the strength of concrete is achieved by fiber reinforcement (glass, carbon or other fibers). Cage out of FRP exhibits elastic properties up to the failure. An overview of the results of experimental studies of concrete specimens FRP cage, including the experiments conducted by the author. The stress and strain formulas based on them can be used to reliability the estimate of the designed structures.

L. A. Panchenko

Wear Resistance of the Surface of the Structural Polyimide Composite Modified with Ceramic Corundum Coating

In this paper, we consider the results of studies of the wear resistance of the surface of a highly filled polymer-carbon composite based on a polyimide matrix modified with α-Al2O3 ceramic corundum corundum layer. To increase the wear resistance of the composite, a layer of ceramic corundum coating based on α-Al2O3 is applied to the surface of a filled, reinforced polymidic matrix by detonation gas-thermal spraying. The coating has a high degree of adhesion to the surface of the polyimide matrix. The thickness of the corundum coating layer is 200 μm. The results of studies of the wear resistance of the surface of a highly filled polymer-carbon composite based on a polyimide matrix modified with α-Al2O3 ceramic corundum corundum layer are considered. It is shown that filling a polyimide composite with modified tungsten dioxide and applying a corundum coating significantly increases its wear resistance. The brittle-plastic fracture mechanism of the polymer composite coated with α-Al2O3 ceramic corundum coating was established, the filler was chipped, and the polymer retained plastic deformation. According to tribological studies, due to the presence of a corundum layer on the polymer surface, no signs of wear are observed.

R. N. Yastrebinsky, V. V. Sirota, A. V. Yastrebinskaya

Fiber Concrete on Greenest Cementitious Binders for Road Construction

The urgent task of the construction industry at present is the search for durable building materials for pavement. Cement concrete in road construction is promising because of its durability and wear resistance. Fiber concrete compositions based on greenest cementitious binders with both steel and basalt fiber have been developed. The microstructure of composites, as well as the characteristics of static and dynamic strength, have been investigated. In the study of crack resistance upon impact stress of fiber reinforced concrete with various types of fibers, it has been found that optimization of the composite structure due to the introduction of fibers made it possible to increase the tensile strength of concrete (before the formation of the first crack) up to 9 times in comparison with the corresponding mixtures without fiber. The developed materials can be used for cement concrete road clothes, as well as for other special applications in the construction of unique buildings and structures.

R. S. Fediuk, A. V. Klyuev, Y. L. Liseitsev, R. A. Timokhin

Development of Composite Binders’ Compositions for Additive Technologies in Low-Rise Building Construction

One of the new advanced technologies in low-rise buildings construction is 3D–printing technology, for development of which creating efficient materials with the required adjustable properties on the basis of hydration composite with micro-, ultra- and nanodispersed mineral admixtures and extenders in combination with hyper- and superplasticizers is necessary. The paper considers the opportunity of obtaining composite binders and quick-setting composite gypsum binders for this purpose. As an active mineral admixture in the binders the opoka marl was used, which demonstrates hydraulic activity at its interaction with Ca(OH)2 with forming low-basic hydrous calcium silicates and other formations. In the process of binders’ structurization with mineral admixtures Ca(OH)2 is fixed and excluded from the reaction. Hydrolysis of clinker minerals is catalyzed; simultaneously the amount of low-basic hydrous calcium silicates like CSH(B) is increased, which positively influences the properties of hardened binders. The findings of the carried-out research confirm the possibility and feasibility of using the OM as an active mineral admixture in compositions of CB and CGB, which would improve their performance characteristics in general, provide quick strength gain of binders at the initial setting time, except for the subsequent self-destruction of the structure due to crystallization pressure.

E. S. Glagolev

Crack Closure in a Cement Matrix Using Bacterial Precipitation of Calcium Carbonate

The article presents the analysis the degree of clogging of mechanically formed cracks by new growths induced as a result of the urease activity of bacteria in model solutions. Intensification of the induction of new formations depending on the type of bacterial culture is characterized by the formation of positive reliefs on the surface of the cement stone. The continuous fouling of the inner surface of the formed fault by crystals of various morphologies formed as a result of the enzyme activity of bacterial strains is visualized. The authors propose the method for calculating the area of an asymmetric fracture with different widths of the convergence of parts. The results of the intensification of precipitation of crystals are determined by the coefficient of crack closure. On the basis of comparative analysis of bacterial cultures by the intensity of continuity reattachment in the fracture zone, they were ranked according to the increase of efficiency of the following sequence: S. pasteurii → B. pumilus → B. megaterium → L. sphaericus.

V. V. Strokova, U. N. Dukhanina, D. A. Balitsky

Stress Modelling of Composite Shallow Shells of Variable Structural Rigidity

The stress state of composite structures of variable structural rigidity is calculated. Composite structures are multilayer plates and shells. Layers of such structures are interconnected by bonds that allow slipping of one layer in relation to another. Such systems have high strength and rigidity. The solution to the problem of determining the stress-strain state of such structures will significantly reduce their material consumption, subject to (in relation to) their reliability and durability. The paper considers composite shells with layers of variable thickness. The parameters of the shell include: the dimensions of the shell in the plan, the thickness of the steel sheathing of the upper and lower layers, the initial thickness of the concrete layer at the borders, the amplitude of the change in the thickness of the middle concrete layer for a given law of change, the stiffness coefficient of shear bonds between the layers. The task of calculating composite shallow shells of variable structural stiffness for strength is to determine the stresses and strains at specific loads and evaluate them from the standpoint of reducing the material consumption of these structures.

S. V. Yakubovskaya, E. Yu. Ivanova

Effective Driven Inclined Open Pile (IOP)

Inclined open pile foundations are arranged in the case of large horizontal and pulling loads acting on the pile cluster. Such foundations are typical for buildings and structures of industrial use and tower type. The load-bearing capacity of such foundations depends significantly on the area of load transfer by the lower part of each cluster forming inclined open pile. This area depends on the geometric parameters of the pile and the divergence angle of the inclined open piles. The process of plunging inclined open piles is very labor-intensive and it is not always possible to achieve the designing divergence angle of inclined open in the conditions of the construction site. The inhomogeneity of the ground conditions of the construction site and additional compaction of the soil around the submerged piles influence on ensuring the design divergence angle of piles during plunging. In this paper, the authors propose the use of a pile opener, which allows ensuring the design opening angle of inclined open piles that compacts the soil in the compressed zone between them. The authors conducted laboratory and mathematical studies simulating the process of plunging and diverging of inclined open piles with the use of a pile opener. The authors also determined the influence of the opening angle of inclined open piles on the load-bearing capacity of the pile foundation under vertical and horizontal loading.

A. E. Naumov, A. V. Shevchenko, A. V. Dolzhenko, S. Yu. Pirieva

Interaction of Potassium Oxide with Calcium Aluminate

The main problem of cement production is the presence of circulation of alkaline compounds. Alkali metal salts are always present in the raw mix of cement production. As it is known, these compounds have a negative impact on the technological process of clinker production, contributing to the formation of rings in chain screens and accretions in cyclone heat exchange devices, and also worsen the strength indicators of cement. To solve the problems of neutralizing alkali metal salts, it is necessary to study the possible chemical interactions of these compounds with raw materials and clinker minerals formed during firing in a rotating furnace in all technological zones of the furnace unit. If chemical interactions in the range of temperatures up to 1100 and above 1300 °C have been studied by many researchers, the range of 1100–1300 °C has been not. This work is devoted to the study of possible interactions between one of the main clinker minerals (calcium aluminate) and potassium oxide, which is involved in the internal circulation of alkaline compounds. The study established firing products between C4AF and K2O at 1200 °C:Stage 1 of the reaction: $$ 4CaO \cdot A{l_2}{O_3} \cdot F{e_2}{O_3} + {K_2}O\mathop \to \limits^{1200^{{\circ}}{\rm C}} 2CaO \cdot F{e_2}{O_3} + {K_2}O \cdot A{l_2}{O_3} + 2CaO $$ Stage 2 of the reaction: $$ 2CaO \cdot F{e_2}{O_3} + {K_2}O\mathop \to \limits^{1200^{{\circ}}{\rm C}} {K_2}O \cdot F{e_2}{O_3} + 2CaO. $$ These reactions can occur at firing temperatures corresponding to the zone of exothermic reactions of a rotating cement furnace, with the arranged return of dust from the hot end of the furnace.

A. O. Erygina, D. A. Mishin

Influence of Polycarboxylate Superplasticizer and Mineral Additives of Various Nature on the Kinetics of Early Hardening Stages of Cement Systems

Influence of the polycarboxylate superplasticizer and mineral additives of various natures (siliceous, aluminosilicate, and sulfoaluminate) on the kinetics of early hardening stages of cement systems, characterized by the rate of increase in the plastic strength of cement paste, have been studied with the recording of the following quantitative indicators: the initial and final setting time, time to reach the plastic strength of 5 MPa. The research results showed that the comprehensive use of organic and mineral additives allowed improving positive influence by means of synergetic effect and eliminating the negative influence of each component individually and thereby controlling the properties of cement paste and processes of early structure formation of cement stone. Introducing the carbonate filler (microcalcilte) into non-plasticized cement system (composition No. 5) decelerates the growth of plastic strength to some extent during the first 4 h of hardening as compared to non-modified composition No. 1 (Fig. 2, a). When it replaces 50% of the complex modifier SF+HAM+ESAM (see Table 1, compositions Nos. 7 and 8_1, respectively), it leads to substantial deceleration of both setting time (from 5 to 7.08 h for initial setting time and 6.08 to 8.33 h for final setting time) and the time to reach the plastic strength of 5 MPa (from 7.0 to 9.4 h). Composition numbers Portland cement Type of mineral additives SP Melflux 1641 F SF HAM ESAM MC % by weight of binder (Portland cement+mineral additives) 1 100 0 0 0 0 0 2 90 10 0 0 0 0 3 90 0 10 0 0 0 4 90 0 0 10 0 0 5 90 0 0 0 10 0 6_1 100 0 0 0 0 0.25 6_2 100 0 0 0 0 0.1 7 90 3.333 3.333 3.333 0 0.25 8_1 90 1.667 1.667 1.667 5 0.25 8_2 90 1.667 1.667 1.667 5 0.1 Table 1. The studied compositions of cement systems (W/(PC+MAs) = 0.27)

T. A. Nizina, A. S. Balykov, D. I. Korovkin

Increasing the Resistance of Building Materials with Bioactive Hybrid Coverage

The paper presents the results of research on the creation of building materials that are highly resistant to the impact of microorganisms using Sol-gel technologies. A modified waste of galvanic production was used as a biocidal component included in the gel matrix. Biological testing of products was performed using bacteria (Escherichia coli, thiobacteria), green algae and microscopic fungus (Aspergillus niger). The effectiveness of the coverage of concrete materials in relation to the listed microorganisms were already evident at the concentration of biocide used in quantities not exceeding 1% by weight of the Sol-gel mixture. Some technological parameters of the process that provides the formation of a protective surface layer of construction products are identified. The duration of contact between the samples and the Sol-gel mixture, which ensures the fungus resistance of the material, was 2 min for ceramic products, and from 30 s to 1 min for concrete products. It is shown that materials with such a coverage are resistant not only to the impact of microorganisms, but also to the effects of other environmental factors, as well as increased strength (there was an increase in the strength of concrete samples impregnated with polymer, on average, by 1.3–1.5 times) and, as a result, high durability.

M. I. Vasilenko, E. N. Goncharova, Yu. K. Rubanov

Features of Expertise in Wooden Housing Construction

Wooden house construction is widely used in individual housing construction. The most popular wooden houses are in the United States, Canada, Scandinavian countries, and Northern Europe. Wooden architecture resumes in Russia after a century and a half of oblivion. But during the long break, skills, experience, and skills of building wooden structures were lost, and qualified specialists were not trained in this production. The lack of qualified specialists’ leads to the fact that serious violations often occur during the construction process, which make buildings unusable or require significant investment to eliminate them. In General, this creates a negative image of wooden housing construction as high-quality and durable. The article deals with typical errors in the construction of foundations for wooden buildings, the junction of the log with the Foundation, which directly affects the durability and quality of the structure as a whole. Typical violations and errors that occur when selecting raw materials, manufacturing wall materials in the form of rounded and hewn logs, glued beams, log construction technology, installation of window and door openings are considered separately. This information is of interest to builders and experts in the field of wooden housing construction, developers and owners of wooden residential buildings.

S. I. Ovsyannikov, A. A. Suska, V. M. Kashyna

Surface Activity of the Fine Disperse Systems on the Basis of Construction Sands

As an energy criterion for ranking raw materials for the production of building materials, it is proposed to use the internal energy reserve of rock-forming minerals. This parameter is related to the surface development and the released free surface energy of the system when the material is dispersed. Based on the principles of crystal energy, two sand deposits in the Arkhangelsk region were evaluated for atomization energy, specific weight energy of atomization, and specific volume energy of atomization (energy density). The quantitative evaluation of the potential energy reserve that passed after the material was ground to the surface one, was carried out taking into account the values of the critical surface tension and the specific surface of the raw material (formed after the process of mechanical grinding). The level of possible use of the potential energy reserve due to the formation of a new material surface was characterized by the activity of the surface of fine disperse samples. It was found that, despite the difference in the chemical composition and origin of rocks, the macro-energy parameters have similar values. The energy density values allow classifying the considered sands as high energy dense. The obtained values of surface tension and surface activity showed that the sands of the Kenitsa Deposit, in comparison with the sands of the Krasnoflotsky-Zapad field, are preferable to be used as an active fine disperse component for producing high-quality compositions.

M. V. Morozova, M. V. Akulova, M. A. Frolova

Optimization of the Structure of Flat Metal Tube Trusses

Loading optimization of the metal trusses has a variational basis. The universal criterion of optimization is the minimum of potential energy of the system (additional energy) in functional space expanded at the expense of functions fields of configuration and (or) material modules, as well load. The proposed variational method of truss synthesis is based on the principle of possible work and generalization of the variational principles of Lagrange and Castigliano by expanding the functional space of geometric parameters. The criterion of equal strength of the truss established in the linear statement of the variational problem creates the prerequisites for finding its optimal topology and geometry when specifying the type of load, directive parameters, mechanical characteristics of the material, and the flexibility of compressed rods. The global minimum potential energy of deformation of the optimal truss corresponds to the global minimum material consumption. As numerical experiment was consider the distribution of load ∑Fi =  const for the truss with descending (ascending) pivot. It is established the independence of optimal loading variant from truss grating structure.

V. A. Zinkova

Composites on the Base of Industrial Waste with Biocidal Components

The article discusses ways of producing bioresistant building materials containing metal nanoparticles obtained from techno genic wastes; procedures for their introduction into building materials based on Portland cement; assessing the bioresistance of the obtained samples of building materials using a wide arsenal of methods, including microbiological methods with a variety of test objects (microscopic fungi, bacteria, unicellular algae). The aim of the study was to identify effective inhibitors of aggressive metabolites of fungi involved in the destructive process of building materials; determination of the mechanisms for the selective isolation of bioactive monoproducts from complex systems that were used as biocidal additives to provide fungi-resistant materials. As a result of experimental studies, a technology was developed for the physical and chemical treatment of industrial waste in order to obtain a biocidal component, the effectiveness of which was confirmed by biological testing methods using microscopic fungi, algae, and bacteria as test objects. The main representatives of the natural algalosis were defined. The measures have been developed to protect materials from biodeterioration by modifying component compositions and technologies for their preparation. The laboratory samples of building materials with predicted resistance to microbiological damage have been obtained.

Yu. K. Rubanov, Yu. E. Tokach, M. I. Vasilenko, E. A. Belovodsky

Assessment of the Durability of Coatings Based on Sol Silicate Paint

Information is given on the operational stability of coatings based on sol-silicate paint. It is shown that coatings are characterized by higher resistance to cyclic freezing-thawing. The values of the free surface energy of the coating are given. It was found that coatings based on sol silicate paint have a higher surface free energy with a predominance of the polar component. Determined that the decrease in the FSE of coatings during freezing and thawing occurs mainly due to the dispersion component. The interfacial interaction between the paint and the substrate is considered. It was revealed that the sol-silicate paint is characterized by high adhesion work, wetting work, which determines the high adhesion strength of the paint to the substrate during freezing. The values of adhesion strength of sol silicate paint with the substrate are given. The analysis of experimental data indicates that the decrease in the FSE occurs mainly due to a decrease in the dispersion component. Thus, after 7 days of wetting, the decrease in the FSE coating based on sol silicate paint was 5.084 mN/m, including the dispersion component - 5.35 mN/m. The decrease after 7 days of wetting the FSE coating based on silicate paint is 9.01 mN/m.

A. M. Gridchin, V. I. Loganina, E. B. Mazhitov, A. N. Ryapukhin

The Role of the Structure and Texture of the Gypsum Matrix in the Formation of Composite Materials

This paper summarizes the results of longtime research on the structure of composite and multiphase gypsum binders and materials based on them. Fine additives CaSO4 II, iron ore concentrate of Lebedinsky MPP, waste flint and container broken glass were used as fillers. It is shown that the physical and mechanical characteristics of composite materials based on gypsum binders largely depend on their structure. And it, in turn, depends on the type of binder, the nature and dispersion of additives and fillers, the ionic composition of the medium and the pH value. In the process of hydration and hardening of composite materials based on gypsum binders, additives and fillers, as a rule, do not change themselves, but significantly affect the formation and growth of gypsum crystals. They change the size and morphology of crystalline neoplasms and contribute to the formation of a denser and more uniform fine-crystal structure of the composite material, which leads to a decrease in their porosity and improvement of physical and mechanical parameters. Three types of dependences of the strength of composite materials on the quantity, nature and properties of the filler additive are proposed.

V. G. Klimenko

Probabilistic Tornado Hazard Criterion for the Nuclear Facilities Siting Areas

Due to the significant potential danger of destructive effects of tornadoes on nuclear facilities (NF), national and international safety standards for NF provide for the study of the climate regime of tornadoes and the organization of appropriate protection of NF. An essential feature of the climate in recent decades is the widespread sharp increase in the number of hazardous weather events, including tornado occurrences. This fact determines the need for statistical processing of data on the tornadoes near NFs and assessment of their characteristics, taking into account the existing tornado hazard criteria for the NF siting areas. This study is focused on evaluating design characteristics of tornadoes using additional data on the tornado occurrences in recent years as well as predicting the risk of tornado hazard in the event of intense tornadoes. On the example of one of the tornado-prone zones in the former USSR, the probability of tornado occurrence was calculated. It has been established that the real danger of tornado impact on the NFs would be possible if two or more additional tornadoes of F5 Fujita scale pass across the survey area. Such a situation is possible with the current trend of climate changes. It is noted that there is a need to provide for the collection and analysis of new meteorological data in order to continue maintaining the existing records of registered tornadoes, as well as to expand the categories of industrial facilities that may be affected by emergency events.

G. P. Barulin, F. F. Bryukhan

On the Issue of Designing Structures of Composite Binders

Additive technologies have expanded the horizons for many dynamically developing areas of production. In many sectors of the national economy, the practical applicability of 3D printing is no longer in doubt, such as medicine, mechanical engineering, radio engineering and electronics. Therefore, the next step in the development of 3D printing technology was the printing of building structures and residential buildings. The use of additive technologies in construction requires the development and study of new materials. Predicting the properties of composites for 3D printing is quite a complex task, the solution of which can be achieved by applying mathematical models that take into account and describe the rheology of mixtures, the optimal distribution of fillers in the material structure, as well as dependencies that assess the impact of microfillers on the operating performance of products. It seems appropriate to use composite binders to produce concrete for 3D printing. Proper selection of all components, the type and optimal amount of additives introduced, will allow regulating the properties of the final product at the design stage. Thus, a systematic approach to determining the quality of concrete is being formed, which allows predicting and directing its properties depending on the goals and tasks being solved by builders and technologists.

R. V. Lesovik, M. S. Ageeva, A. A. Matyukhina, E. V. Fomina

Composite Binders Based on Dust of Electric Filters

This paper discusses and suggests ways to use desalinated waste dust of electric filters as an individual or complex binder. The aim is to identify the possibility of the use of dust of cement plant electric filters as a binder material; to select the ratio of Portland cement and dust of cement plant electric filters in the composite bundle to develop a new kind of binder; to study physical and mechanical properties of samples of the binder and determine the most promising compositions. The objectives of this work are: to study sampling of samples; to create a composite solution based on Portland cement, electric filter dust and various types of sand; to study the microstructure of the source material and to develop a composite binder with improved strength and hydration characteristics. In this paper, a comparative analysis of Portland cement PC500-D0-N and waste dust of cement plant electric filters was performed; their granulometry, chemical and mineralogical compositions, micro-structures and physical and mechanical characteristics were studied. As a result, the feasibility of using the enriched dust of electric filters as an independent binding material or in a composite bundle with Portland cement was proved, and a promising direction for creating a complex binder was identified.

L. H. Zagorodnyuk, V. D. Ryzhikh, D. A. Sumskoy, D. A. Sinebok

Influence of Chloride-Containing Media on the Protective Properties of Concrete

The main factor causing the destruction of reinforced concrete is the corrosion of steel reinforcement, about 80% of the damage is due to this phenomenon. Chloride-containing media are aggressive both to cement concrete and to steel reinforcement. Experimental studies of liquid corrosion of cement concretes in chloride-containing media were conducted: in 2% MgCl2 solution and in hydrochloric acid solution with pH = 5. It is established that at the initial stage of concrete corrosion in liquid media, their strength increases due to the formation of corrosion products in the pores. The influence of the type of concrete coating on the electrochemical corrosion of steel reinforcement located in concrete is studied. In concretes containing hydrophobizing additives, the corrosion of steel reinforcement occurs much later compared to the reinforcement found in non-hydrophobized cement concretes. During 6 months of testing, changes in the surface potential of steel reinforcement in hydrophobized concretes exposed to media of various degrees of aggressiveness were not recorded. The studies and data obtained give an idea of the influence of various media on the development of the corrosion processes of reinforcement and concrete and serve as the basis for clarifying the features of corrosion and methods for its elimination in the system “steel reinforcement – concrete”.

Viktoriya Konovalova

The Effect of Latex and Nanocarbon Modifiers ON the Properties of High-Strength Gypsum

It is known that gypsum binders and products based on them are effective building materials and are characterized by high technical and economic indicators of production and use in construction, and gypsum products also do not require acceleration of hardening in their manufacture. We can highlight the disadvantages of gypsum materials and products. These are relatively not high strength characteristics and low water resistance. It is possible to reduce the negative properties and increase the operational characteristics of gypsum building products by modifying gypsum binders, creating mixed forms of binders and composites with specified characteristics on their basis. Moreover, complex systems based on gypsum binders are not always stable in their properties and are often unpredictable in difficult operating conditions. The aim of our study is to study the mechanisms of influence of latex, nanocarbon, as well as complex latex-nanocarbon modifiers on high-strength gypsum of the industrial brand G-16.

L. Yu. Matveeva, M. V. Mokrova, A. V. Yastrebinskaya, A. S. Edamenko

Smalt Based on The Broken Colored Container Glasses

Areas of use of glass industry waste in the production of various types of products are analyzed. The possibility of using broken colored container glasses for the production of smalt is considered. It was experimentally confirmed that due to the introduction of liquid glass into the glass powder, the firing temperature of the smalt decreases. The optimal sintering temperature of tiles was experimentally determined. The micro-hardness of smalt based on blue and olive container glass without adding liquid glass and with the addition of liquid glass of different concentrations was studied. The dependence of the influence of liquid glass concentration on micro-hardness is established. The obtained results indicate that the optimal content in the mixture is 20% of the aqueous solution of liquid glass. The rational firing temperature is set at 700 °C for blue smalt and 725 °C for olive smalt, at which maximum micro-hardness is observed. A wide range of colors, as well as a variety of forms of smalt allows using it in the interior of any style direction. It is also very valuable at finishing bathrooms, pools, as it has zero water absorption, low abrasion, no pores. The use of secondary raw materials will make it possible to reduce significantly the cost of production and increase the competitiveness of smalt.

N. I. Bondarenko, D. O. Bondarenko, K. A. Valuiskikh

Possible Criterion for Evaluating the Compatibility of Components in the Building Mixtures

In this paper, based on the theoretical provisions of the theory of molecular interaction, the results of testing the algorithm proposed by the authors are presented for calculating the Hamaker constant as a characteristic of the dispersion interaction based on experimental data obtained during the study of a composition of fine powders of basalt and polymineral sand. The concept of the Hamaker analog constant is introduced; the method of determining and calculating it is based on a number of assumptions. The desired constant was calculated based on the measured equilibrium angles of wetting the surface of the dispersed material with liquids with known surface tension values. Water solutions of ethanol with different volume concentrations of the organic component were used as such liquids. For the correct application of water-alcohol systems in the proposed method, the physical and chemical constants of the water-ethanol system are calculated. It was found that the change in the structure of the powder composition allows controlling the intensity of the van der Waals interaction in the mixture, which is quantified by the value of the Hamaker constant. This fact makes it possible to select restoration (repair) construction compositions that are characterized by an increased affinity to the main material. The proposed experimental approach and algorithm for calculating the van der Waals interaction constant in fine powder systems can be used for compiling an informational reference database.

A. M. Ayzenshtadt, A. A. Shinkaruk, M. A. Frolova

Influence of Modified Bituminous Binders on the Properties of Stone Mastic Asphalt

One of the important reasons for reducing the service life of asphalt concrete surfaces (ruts, plastic deformations, potholes, cracks, etc.) is the low quality of used road oil bitumen. This determined the relevance of the development of bituminous binders with increased physical and mechanical properties. This is especially true for organic binders that are used in the production of Stone Mastic Asphalt (SMA). The paper presents the results of a study of BND 70/100 bitumen modified by the introduction of polymers (atactic polypropylene APP and styrene-butadiene thermoplastic SBS L 30-01A), using a single-stage technology for preparing a polymer-bituminous binder. The influence of binder modification on the physical, mechanical and operational properties of road asphalt concrete is shown on the example of Stone Mastic Asphalt (SMA-20) relative to the basic samples made to control the dynamics of changes in the properties of composites. A comprehensive assessment of the effectiveness of modifying the composite based on various binders was performed on the basis of generalized quality criteria obtained by determining the partial quality criteria of the composite, taking into account the weighting coefficients. The comparison and analysis of the obtained performance criteria is made. The comprehensive assessment of the performance indicators of binders and composites based on them demonstrates that obtaining an objective conclusion about the quality of bituminous binders is not correct without investigating their influence on the properties of the final product, in the case of SMA.

D. A. Kuznetsov, A. V. Kurlykina, A. O. Shiryaev, D. P. Litovchenko

Physico-Chemical Properties of Fuel Ashes as Factor of Interaction with Cationic Bitumen Emulsion

To maintain the stability of bitumen emulsions, the constancy of the hydrogen index of the introduced components is of great importance. However, the establishment of the pH value of the water extraction of fuel ashes does not allow fully assessing the effect and giving a reliable predictive assessment of the stability of the emulsion in the cationic bitumen emulsion – fuel ash system. The paper presents the results of a comparative assessment of four types of fuel ashes with three indicators: acid-base properties, their electrokinetic potential in an aqueous medium, and the hydrogen index of an aqueous extract from a water-ash solution. The methods used for assessing the physicochemical properties of fuel ashes are necessary but, not all are informative in terms of assessing their potential and effectiveness in using cationic bitumen emulsion. It is shown that assess the effect of evils on the decay rate of a cationic bitumen emulsion, the H0 and ζ-potential are the most informative for use in the rapid assessment of the possibility of using this type of technogenic raw material. The studied types of ash were ranked to reduce the degree of negative influence on the stability of the cationic bitumen emulsion.

A. Yu. Markov, V. V. Strokova, I. Yu. Markova, M. A. Stepanenko

The Study of Bitumen with Stabilizing Additives for SMA by Infrared Spectroscopy Method

Increasing the volume of macadam-mastic asphalt concrete used in the upper layers of road surfaces requires the development of effective stabilizing additives that ensure the uniformity of the asphalt mix during short-term storage and transportation, as well as improving the properties of asphalt concrete. Such additives include the complex stabilizing additive of the following composition: 90% cellulose fibers from waste paper, 5% rubber powder, 5% viscous petroleum bitumen of the ORB 90/130 brand. This article presents the results of a study of bitumen with the additive “Viatop 66” and the complex cellulose-containing stabilizing additive (CSA). Using the method of IR-Fourier spectroscopy, graphical data were obtained, as a result of their analysis, it was found that the interaction of stabilizing additives for macadam-mastic asphalt concrete with bitumen leads to the occurrence of additional absorption bands characteristic of aromatic compounds (CH, benzene ring), sulfur-containing functional groups S = O st, R-SO-R, R-SO-OH, R-SO2-R, C = S st, as well as for groups C-O-H. X-ray spectral analysis confirmed the presence of additional sulfur-containing spectra in the composition of stabilizing additives. It was found that depending on the chemical composition of stabilizing additives, the physical and mechanical characteristics of the bituminous binder and the resulting asphalt concrete change.

Dmitry Yastremsky, Tatiana Abaidullina, Petr Chepur

Composite Binder on the Basis of Concrete Scrap

The object of research is to obtain binders from fragments of destroyed buildings and structures for the production of various building elements. The properties of fractions (0.0–0.16 mm, 0.16–0.315 mm, 0.315–0.63 mm, 0.63–1.25 mm, 1.25–2.5 mm and 2.5–5 mm) obtained from fragments of destroyed buildings and structures were studied. Using known chemical and physical methods, experimental results were obtained on the influence of the fraction size and specific surface area on the degree of hydration of binders during the hardening process. It was found that the amount of alite and belite decreases with the transition from the 0.0–0.16 mm fraction to the 2.5–5 mm fraction. At the same time, the amount of quartz and minerals increases that are characteristic of a large aggregate. The smallest fractions of concrete scrap (pulverized and 0.16–0.316 mm) contain the maximum amount of alite C3S and belite C2S, which can harden when interacting with water, compared to larger fractions. To evaluate the ability to hydraulic hardening, the obtained fractions of concrete scrap were crushed in a laboratory mill to a specific surface area of 316–387 m2/kg. The maximum compressive strength was shown by samples of fractions 0.0–0.16 and 0.16–0.315 mm 6–7 MPa. Thus, the greatest hydraulic activity was shown by powders of two small fractions that hardened both under normal conditions and during steaming. Their compressive strength is 1.5–2 times higher than that of samples prepared from powders of larger fractions.

R. V. Lesovik, N. M. Tolypina, Ahmed Anees AlAni, Al-bo-ali-wathiq Saeed Jasim

Properties and Microstructure of Gypsum Stone with Synthetic and Protein Foaming Agents

The influence of synthetic (Penostrom) and protein (Foam X) foaming agents on the physical and mechanical properties and microstructure of gypsum stone obtained by dry mineralization of low multiplicity foams (4–6) with high-strength separated gypsum was studied. When using foam based on the foaming agent Penostrom, the average density of gypsum stone is reduced to 430 kg/m3 (by 3 times), the coefficient of thermal conductivity to 0.14 W/(m·°C) (by 4 times), the compressive strength to 2.4 MPa (by 6 times). Foam based on foaming agent Foam X increases the compressive strength of gypsum stone to 17.5 MPa (by 1.2 times) with a slight increase in the average density (by 3%) and the coefficient of thermal conductivity (by 5%). It was found that the microstructure of gypsum stone with Penostrom is represented by large-dispersed crystals of calcium sulfate dihydrate of plate-acicular morphology, meso pores (diameter 3.5–33 nm) with volume of 43∙10−3 cm3/g, macro pores (diameter 60–130 nm) with volume of 30∙10−3 cm3/g. The microstructure of gypsum stone with Foam X is characterized by the content of fine-dispersed, densely packed crystals CaSO4∙2H2O of prismatic habitus, meso pores (diameter 3.5–33 nm) with volume of 57∙10−3 cm3/g, macro pores (diameter 60–130 nm) with volume of 19∙10−3 cm3/g.

N. P. Lukuttsova, A. A. Pykin, S. N. Golovin, E. G. Artamonova

The Effect of Separate Input of the Mineralizer on the Whiteness and Strength Characteristics of White Cement

This article is devoted to studies to establish the effect of separate input of the mineralizer on the properties of white cement clinker. In the course of the research, the 2C2S·CaF2 mineralizer was separately introduced into the raw material mixture for the production of white cement, prepared from the chalk of the Belgorodsky cement deposit and the kaolin of the Zhuravlinny log deposit. It was found that the separate input of the 2C2S·CaF2 mineralizer increases the whiteness of white cement clinker by 10–16% abs. and contributes to clinker with a shade closer to white than without a mineralizer. The separate input of the 2C2S∙CaF2 mineralizer allows achieving almost complete assimilation of calcium oxide even at a temperature of 1300 °C. The phase composition of the samples obtained by separate input of the 2C2S∙CaF2 mineralizer is identical to the samples without a mineralizer, except for the C12A7. Separate input of the mineralizer does not adversely affect the compressive strength of white cement samples. The phase composition of the hydration products does not differ from the phase composition of the control samples without the mineralizer.

S. V. Kovalev, D. A. Mishin, E. V. Neverova

Influence of Compatibilizator on the Operational and Technological Properties of Thermoplastic Composites Filled with Fine Barley Straw

The paper considers the problem of combining a non-polar polymer matrix and a polar agricultural origin filler in thermoplastic composites. The following types of modifiers were used during the study: Maleid F, activator BKT-2, chlorine paraffin HP1100. The research objective was to evaluate the possibility of using these modifiers in thermoplastic composites with a polymer matrix. Chopped barley straw with a particle size of 200 … 300 microns and a moisture content of 6.5% was used as a agricultural origin filler. Components compounding was carried out on a HAAKE PolyLab 600 OS two-rotary blender mixer at a temperature of 150 °C and rotor speeds of 50 rpm. Samples for physical and mechanical, and rheological characteristics were obtained by compression molding on a Gibitre hydraulic press. The following operational and technological characteristics were determined for the obtained composites samples: tensile strength and tensile modulus, water absorption, density, dependence of dynamic viscosity and dynamic elastic modulus on the rotor angular velocity. It has been shown that the introduction of 5% of the studied modifiers significantly improves the physical and mechanical characteristics, while maintaining the manufacturability of the compositions.

A. M. Kuzmin

Remote Method for Predicting Damage to Cement Concrete Pavements

One of the important tasks of optimal design of road structures is the development of methods for predicting their service life, which allows evaluating objectively the state of road structures that are being designed or are already in operation with minimal labor and financial resources. The paper offers mathematical models that allow predicting various types of damage to cement concrete pavement during their service life. The models were developed by analyzing an array of damage data on the current network of roads with cement-concrete pavement in Russia, obtained using the Internet resource Google Maps. On the basis of the obtained data of fixing damages of cement-concrete pavements of roads, dependences of the intensity of damage formation of cement-concrete pavements over a long period of operation, comparable to the service life of cement-concrete pavements, were obtained. The character of development dynamics of damages of cement-concrete coatings of road pavements was revealed; the stages of their occurrence were established. The proposed models can be useful for design, construction and maintenance organizations and can be used for evaluating design decisions, for quantitative and objective evaluation of deviations in the quality of construction, as well as for timely planning of work based on constant monitoring of the existing road network.

A. A. Fotiadi, S. A. Gnezdilova, I. S. Strekha

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