bluuebunny/crossref_metadata_2025 huggingface dataset:
Durability of Concrete with Man-made Thermoplastic Sulfur Additive
Authors: Gumeniuk Aleksandr , Hela Rudolf , Polyanskikh Irina , Gordina Anastasia , Yakovlev Grigorij
Published: July 2020

In the article, the data on sulfur surface modification and its influence on the properties of common cement mix and concrete are discussed as well as durability and corrosive resistance of modified compositions. The composite components, conditions of mixtures making, and required temperature treatment were established in the laboratory testing. The potentiometric model was used to assess the interaction between the corrosive environment and the modified composites, a corrosive agent being used as a sulfate environment. This model takes into account the change in reaction potentials and is used as an index of the solvolysis reaction between the sulfate solution and constituents of the modified cement matrix. This modelling determined two main characteristics used to predict the durability of building material. These are the depth of corrosive agent in the material structure and the amount of solved calcium hydroxide. The established data show the potential usefulness of the modified additive based on man-made sulfur as an additive for cement composites. The modified additive can be used for materials with a high performance and durability in an aggressive environment. The increasing of corrosive resistance might be explained by the structure changing and by the properties of the formed crystalline hydrates.
The efficiency of sulfur modifier to neutralize toxic gases in sulfur-asphalt concrete technology
Authors: Tuan Le Huu , Inozemtcev Sergey , Korolev Evgeniy , Grishina Anna
Published: July 2020

Studies of the advantages of sulfur-asphalt concrete with toxic gas emission neutralizers show that the use of neutralizers reduces the amount of emission of these gases and improves the environmental problem of the use of sulfur-asphalt concrete. Zinc oxide and zinc oxide are not effective in neutralizing hydrogen sulfide and sulfur dioxide. Reducing the emission of toxic gases using dolomite and diatomite is due to the ability of carbonates to neutralize sulfur dioxide through chemical reactions, as well as absorb gases into the porous structure of grains. Other considered neutralization reactions and side processes according to the calculations mainly occur. The processes of interaction of neutralizers with toxic gases and secondary processes can proceed according to various chemical reactions, however, chemical reactions with the release of more energy occur predominantly. This is confirmed by experimental studies. As a result of theoretical and experimental studies, a list of effective toxic gas neutralizers has been established, the emission of which occurs when bitumen interacts with a sulfur modifier.
Insulation system of low-rise buildings on a wooden frame
Authors: Fedyukova Margarita , Kartashov Artem , Veremeev Daniil , Zhukov Alexey , Ushakov Andrey
Published: July 2020

Residential development of agricultural territories involves the use of low-cost construction solutions to provide housing for emerging new farms or implemented during the development of gardening plots. In this case, it is advisable to construct frame buildings with effective insulation systems.

The article presents the results of studies of the properties and application features for warming wooden structures of rolled foam polyethylene with or without a metallized coating. The tensile strength tests in the longitudinal direction were carried out in accordance with the standard. It was found that the tensile strength in the longitudinal direction for products with a metallized coating is 80–92 kPa, without a metallized coating – 80-87 kPa, and for a weld - 29-32 kPa.

As a result of the studies, insulation systems were developed (which have found wide practical application) and a full-scale thermophysical assessment of the thermal characteristics of these systems and the condition of the wooden frame in the building was carried out.

The results of experimental determinations of the resistance of the outer wall of a wooden frame with a warming sheet of foamed polyethylene amounted to: thermal resistance 2.96 m2 °C / W, heat transfer resistance 3.12 m2 °C / W. The specific humidity of the pine timber was 7.7–7.8% - at the level of equilibrium humidity values. No putrefactive manifestations of the wooden frame were found, which confirms the advisability of using these insulation systems for the construction of rural residential buildings.
Pelletized fly ash aggregates use for making eco-friendly concrete
Authors: Bach D T , Hoang V L , Nguyen N B
Published: July 2020

Today Vietnam is facing a seriously environmental challenge in handling fly ash and bottom ash from coal power plants with annual emissions of up to 15 million tons. Using the coal ashes to produce building materials is considered a main solution for this issue. Due to shortage of natural aggregates, using the ashes as aggregates in concretes achieves many benefits. This paper presents research results of pelletizing fly ash to produce an aggregate for concrete. The fly ash aggregates had strength of about 3.1 MPa, apparent specific gravity of 2.1 g/cm3, bulk dry specific gravity of about 1450 kg/m3 and water absorption nearby 22%. The concrete made from a combination of fly ash and bottom ash aggregates had the density of about 2000kg/m3 and the compressive strength of 17.5- 46.3 MPa at 28 days. Moreover, the aggregates were also applicable to manufacture ACOTEC wall panel with properties met requirements of TCVN 11524:2016.
Study of the phase composition of nanomodified biocidal cement stone by X-ray analysis
Authors: Grishina Anna
Published: July 2020

Due to high importance of cement concrete for construction industry it is essential to discover new ways towards increasing the durability of the concrete. The problem of low durability is of highest significance in case of hot and humid operating conditions. We have discovered that some biocidal modifiers are able to not only to solve their primary objective, but also may lead to higher resistance of concrete since they change the chemical composition of the cement stone. The results of the study of cement stone by X-ray phase analysis are presented in the article. It has been established that zinc hydrosilicates slow down the hydration of cement, and, thus, can successfully be used as agents which lead to increase of the concrete’s durability in hot climate.
Influence of drying temperature on compressive strength of geopolymer binder
Authors: Ngoc Lam Nguyen
Published: July 2020

Environmentally friendly materials with low CO2 emissions have become an inevitable trend of the construction industry. This requires research establishments to develop new construction material products and manufacturing enterprises to tale the chance and change production directions to meet the needs of the market. Among those new materials, Geopolymer materials promise to contribute to the development of increasingly sustainable construction. This paper aims to study the effect of drying temperature and drying time on compressive strength of geopolymer binders made from type F fly ash, ground granulated blast furnace slag combined with activators solution, including 10M NaOH caustic solution, liquid glass. Research results show that when the drying temperature increases from 60°C to 120°C and the drying time increases from 6 to 24 hours, the compressive strength of geopolymer binders could be enhanced from 2.5 to 3.0 times, compressive strength can reach over 50MPa, fully meet the requirements of the strength of binders used for manufacturing building materials products in civil engineering and industrial construction.
Radiation resistance evaluation of HCP with superplasticizers using DSC
Authors: Medvedev Vyacheslav
Published: July 2020

Today, when constructing new nuclear power plants, they most often start from the data of studies conducted more than 50 years ago. At the same time, the modern achievements of construction science, such as high-tech concrete compositions using highly effective admixtures, are applied either without preliminary studies with irradiation, or are not applied at all. In this paper, we consider the mechanism of radiation-thermal changes in concrete under the influence of neutron irradiation, as the most dangerous factor in the external impact on the design of modern nuclear power plants. The methodology for assessing the radiation resistance of concrete developed by domestic specialists, as well as the possibility of using the differential scanning calorimetry method as part of a comprehensive assessment of the effect of modern admixtures (using the example of superplasticizers) on the radiation resistance of concrete, is considered. It was proved that when analyzing the effect of admixtures on the radiation resistance of concrete, it is sufficient to conduct studies on the HCP rather than using concrete. To analytically establish the effect of superplasticizers on the radiation resistance of HCP, polycarboxylate superplasticizers of well-known brands with short side chains and insignificant steric effect, as well as long side chains and high steric effect. The general behaviour of HCP with superplasticizers was observed using DSC.
Assessment of the effect nitrites and fluorides on the change in the strength of concrete
Authors: Davidyuk Artem , Rybnov Dmitriy , Goglev Ilya , Truntov Pavel , Burkov Artem
Published: July 2020

The article describes examples of using inorganic salts and their mixtures for accelerate of hardening cement concretes in practice of modern construction. The results of the research of a complex mixed additive based on inorganic fluorides and nitrites, which accelerate the process of hardening of cement concrete are presented. The composition of the additive allows to accelerate the process of hardening the cement stone, due to the formation of dense and insoluble compounds in the pores of the cement stone. The experimental part included the process of determining the optimal amount of fluorides and nitrites in the additive. The results of the research showed a reduced additive consumption per 1m3 of heavy concrete. The advantages and disadvantages of the additive, which identified at experiments, allow us to recommend its use for accelerating the hardening of concrete in wet neutral and slightly acidic environments. The methods of tests that were carried out using certified and calibrated measuring instruments are described in detail. According to the results of the tests, the dependence of the concrete hardening rate on the amount of additive used was revealed, and the ways of practical use of the additive in the production technology of concrete and reinforced concrete were proposed. Also, according to the results of destructive and non-destructive testing, an increase in the strength of concrete by >15% compared to conventional concrete was found.
Structure formation of plasticized cement systems under heat-moisture treatment
Authors: Leshkanov Andrei , Dobshits Lev , Anisimov Sergey
Published: July 2020

Reducing the water-cement ratio is successfully achieved using superplasticizers (SP). However, their use can reduce the early strength of concrete and reinforced concrete. Heat-moisture treatment (HMT) is the leading way to accelerate concrete strength. The use of the latest SP based on polycarboxylate esters (PCE) allows adjusting the HMT mode, in particular, to reduce the presteaming period duration. The structure formation of cement pastes was studied depending on PCE modification and the presteaming period duration. The authors show PCE effectiveness in terms of reducing the water-cement ratio and joint action with HMT. It was found that the most effective use of low PCE dosages when using HMT. Increasing the amount of introduced SP to 1.2-2.0 % doesn’t lead to significant changes in initial and final setting times of cement pastes. The results of the study of cement stone compressive strength after HMT and on the 28th day, also the density and capillary porosity revealed a slight deterioration of these physical and mechanical properties (up to 5-10 %) when the presteaming period was abandoned. The results of X-Ray Diffraction analysis indicate no significant differences in the mineralogical composition of cement stone, which hardened at the HMT with the presteaming period of 2 hours and without it. The study of the cement stone microstructure showed that the PCE introduction in cement pastes contributes to the stone structure compaction and reduction of the number of pores. There were no significant changes in the cement stone pore structure, depending on the presteaming period duration. The conducted research shows that it is possible to regulate the HMT modes for the hardening of cement systems with SP.
Comparison of autogenous shrinkage measurements by different methods in case of fast-hardening mortar
Authors: Nguyen Ngoc-Lam
Published: July 2020

Autogenous shrinkage in the volume of cementitious materials results from changes in the microstructure and environmental conditions. These deformations can be sufficient to cause premature cracking of structures, especially the fast hardening materials or thin products with large exchange surfaces, such as paving, screeds and cement-glass composite. The appearance of cracks influences the quality and aesthetics of the works. The dimensional variations can be observed immediately after the cement and the water have been brought into contact during mixing. In this research, the endogenous shrinkages of a fast hardening mortar based on ettringite binder were studied with different methods. In this mortar, there is not only the shrinkage phenomenon but also the swelling relating to the early ettringite formation. Therefore, the understanding of the dimensional variation with different measurement methods is very important. The results indicate that the endogenous shrinkage measured by linear methods and volumetric methods are in good agreement. All measurement method well recorded both a quick shrinkage and a swelling phenomenon in the mortar.
Methods of increasing the resistance of concrete to catastrophic failure in a fire
Authors: Semenov Vyacheslav , Bazanov Sergey
Published: July 2020

A characteristic feature of modern building industry is an increase in the construction of high-rise, technically complex and unique objects. A special role in ensuring the safety of objects of this kind is played by fire protection of load-bearing structures. The aim of this work was to review existing solutions aimed at increasing the fire resistance of reinforced concrete structures in order to ensure normative indicators. The research method is theoretical analysis. The issue of protecting reinforced concrete structures from brittle destruction of concrete in a fire is considered in detail. It has been established that a very effective way to maintain the integrity of a reinforced concrete structure during fire exposure is to modify the composition of concrete and control the structure in order to create a certain pore volume in concrete. The available data on the use of such methods are mainly empirical. The influence of qualitative and quantitative indicators of the additives used, the possibility of combining various methods to increase the fire resistance of concrete, modes of heating structures in a fire, and others are not sufficiently studied. These tasks seem relevant and require additional research.
Measures to prevent sewerage odor emissions into the atmosphere
Authors: Ryltseva Yuliya , Orlov Vladimir
Published: July 2020

The transportation and treatment of the urban wastewater involves the formation and emission into the environment of fetid substances: sulfur and nitrogen compounds, volatile fatty acids, aldehydes and ketones. Fetidly smelling odors of a sewage system are formed as a result of the anaerobic biological decomposition of organic substances (proteins, carbohydrates), the presence in the wastewater of sulfate-reducing microorganisms that receive energy through the organic substance oxidation. The article considers the methods for determining harmful gaseous substances through chemical and organoleptic analyses, presents a list of the methods used in the Russian Federation and abroad for determining fetidly smelling substances, as well as investigating the advantages and disadvantages of the measures aimed at fighting against fetid odors. Each of the given methods has been implemented using constructional and (or) operational means. It has been stated herein, that the odor neutralization, a correct choice of operational and technical measures, construction technologies, design and hardware solutions (choice of the equipment) require a preliminary surveying of the objects of fetidly smelling substances along the whole pipeline system as part of thorough design and technological studies. The theoretical significance of the research consists in searching for the causes of the gas fetid smells, their intensity control methods and the ways that prevent formation and minimize negative manifestations by construction and operational means. The practical relevance of the performed studies is in a possible application of the got results by the specialists of the sewage system designing and public utility servicing works.
Cavitation-abrasive wear working collectors of pumps
Authors: Glovatsky Oleg , Ergashev Rustam , Saparov Azamat , Berdiev Mustafo , Shodiev Bobur
Published: July 2020

The main results of the study of hydraulic losses in the suction line and mechanical damages of the impellers of pumps due to cavitation-abrasive wear are given in the article. The scientific task of using theoretical bases for justifying factors affecting the wear rate of pump parts is being solved. On the basis of these theories, a technique is proposed for calculating the wear rate of the elements of the flow-through part of the pumps. During the experimental studies, standard methods of laboratory-bench testing of pumps were used. The operating modes of pumps with minimal wear of their parts are established. Poor hydraulic flow conditions with swirl zones cause an increase in energy losses and a redistribution of flow rates across sections. Wear the parts that are flowing directly proportional to the concentration in the sediment flow, the cube of the flow velocity, the time of action on the pump units. The presence of unsteady vortex regions, especially when the effect of eddy formation increases, leads to fluctuations in the velocities and pulsations of the flow pressure. Cavitation in the pump occurs when the operating modes of the pump differ from the nominal. The increase in volumetric efficiency, the improvement of hydraulic flow conditions to the pump impeller and the reduction of cavitation wear were achieved by the authors in a new pump design that contains guide planes fixed to the throttle plate parallel to the suction nozzle axis with an elastic outer surface. In the same areas of constructive improvement of pump assemblies, it is necessary to search for ways to reduce the negative impact of cavitation and hydroabrasive erosion on the life of pumps.
Interaction of sorption and hydrodynamic phenomena during water filtration
Authors: Vikulina Vera , Vikulin Pavel , Mamina Gyuzyal
Published: July 2020

The paper presents the concept of sorption and surface phenomena, as well as ion exchange. These processes are accompanied by absorption or exchange of ions due to the free energy of the surface layer of the solid phase. It is proposed to consider the process of ion exchange between the solid and liquid phase during filtration. As a solid phase, synthesized loading is used, which is used in various industries. It is noted that the synthesized load has high mechanical strength and chemical resistance. It is indicated that the size and shape of the loading grain affects the ion exchange rate and hydraulic resistance. The dependence taking into account the free energy of the loading surface and the mechanism of ion exchange in the equivalent dependence is given. Technological characteristics of some types of loading are shown. The duration of filtration is determined by the appearance of dissociated ions in the filtrate and depends on the exchange capacity of the load. Static and dynamic exchange capacities are allocated. The relevance, purpose and objectives of the work are formulated. A scheme of fluid motion through the elementary loading layer is proposed for the mathematical description of the process. The increment of substances in the elementary loading layer is described and the conditions of fluid flow around the loading grain of spherical shape are formulated. The reduction of ion concentrations in the elementary layer is mathematically shown. The concentration gradient is obtained as a partial derivative with two variables. The condition of fluid flow around the loading is introduced, based on the processes of hydrodynamics. The flow pattern of the loading elements depends on the Reynolds number. With the help of mathematical and physical analysis, a theoretical dependence was obtained, which relates the initial concentration of the studied substances in water, the metabolic capacity of the load, the hydrodynamic and physical parameters of the flow. The performed theoretical studies allowed to substantiate the conclusions of this work and to formulate a conclusion about the influence of flow hydrodynamics on the change of absorption of substances from water by loading.
Research of operation efficiency of side-stream membrane bioreactors
Authors: Makisha Nikolay , Pervov Alexei
Published: July 2020

Membrane bioreactors nowadays are intensively applied in wastewater treatment worldwide. Such type of treatment systems have a large scope of implementation at facilities of different capacity. A detailed study required to analyze how to implement reconstruction of WWTP by means of membrane equipment that can be located close to existing facilities of biological treatment in small containers without the installation of new capital containers is required. Following that goal there is a certain interest to investigate the operation of side-stream membrane bioreactors under various pressure conditions and to compare its corresponding efficiency and costs (capital and operation). The paper is focused on estimation of operation parameters (backwash frequency, power consumption and specific energy consumption) for three values (1,6 g/L, 2,5 g/L and 7 g/L) of mixed liquor suspended solids (MLSS) if the filtration goes under pressure of 0,5 bar.
Increasing heat efficiency by changing the section area of the heat transfer pipelines
Authors: Arifjanov Aybek , Xodjiyev Nosir , Jurayev Sherali , Кurbanov Кozim , Samiev Luqmon
Published: July 2020

On the territory of our republic, individual boilers are widely used for heating many social facilities in the winter season. The efficiency (efficiency) of these heating boilers is only 70-75%. Sustainable and efficient use of fossil fuels is now becoming a problem not only in Uzbekistan, but throughout the world. In recent years, the results of expert research on the use of solid, liquid and gaseous fuels in heating boilers show that in many countries there is a shortage of fuel and problems with the supply of natural resources to these countries. Of course, given the fact that the process of burning fossil fuels depends on the cross-sectional area of heating boilers, it is necessary to develop recommendations for creating more energy-efficient use of methods to reduce fuel consumption or resource conservation. In our republic, a number of scientific works are consistently carried out to create resource-saving capacities for heat transfer pipelines. In particular, the main content of the dissertation is the development of the introduction of the latest modern scientific methods to increase the efficiency of heating boilers by improving the method of calculating resource-saving heat transfer pipelines. The article presents methods for determining the heat transfer parameters of heat exchangers in laboratory conditions, as well as methods for analyzing the results.
Evaluation of the hydraulic and morfometric connections of the riverbed with using GIS
Authors: Atakulov Dinislam , Babajanov Farrukh
Published: July 2020

Currently, in the country developed models with using on GIS technologies are mainly based on linear schemes of location and mapping of water resources, and there is no database for determining the state of water resources, hydraulic structures, and river and riverbed deformation. The main problem with the use of GIS models in water management is their low accuracy, the fact that created models were based on low-resolution satellite imagery and used old analytical techniques. Models in irrigation systems which used GIS technologies are one of the problems waiting their solution. In this article analyzed possibility of GIS estimation of deformation processes in the river bed (in case of Sokh River). The processes in the riverbed were analyzed based on satellite data and compared with field experiments. Given conclusions based on analysis.
An investigation of human comfort criteria for footfall induced floor vibrations
Authors: Nguyen Tuan H A , Nguyen-Van Hieu , Dao Nhan D
Published: July 2020

Human comfort is becoming a vital serviceability requirement when it comes to design of long-span floor systems, as evidenced by the development of international standards on human exposure to vibrations. This paper discusses experimental findings derived from dynamic testing of a real office floor of steel-concrete composite construction where annoying footfall-induced vibration had been reported by the floor tenants. The fundamental frequency of the problematic floor was determined using measurements obtained from a series of simple heel drop tests. The observed vibration levels of the floor under normal walking excitations was then benchmarked against acceptance criteria suggested by a number of widely used floor vibration design guides. From a human comfort perspective, it is found that the same floor can be classified as unacceptable by some guidelines but deemed extremely acceptable by the others. As response levels are translated inconsistently by various acceptance criteria, designers would hence be placed in a dilemma when deciding whether the existing floor really needs modification to enhance its serviceability.
On the crack-tip asymptotic fields
Authors: Kuznetsov Sergey
Published: July 2020

Analytical expression between the vectorial stress intensity factor (SIF) and displacement discontinuity intensity factor (DDIF) is derived for an arbitrary shaped plane crack with a smooth crack boundary. The crack is placed in an elastic anisotropic medium with monoclinic symmetry (syngonium). The analysis is based on constructing the outer and inner asymptotes for the corresponding surface stress and displacement discontinuity fields at the crack boundary. The closed form operator of the class -1 in Hörmander 1/2-space of the theory of cracks along with the associated amplitudes and symbols are constructed. Both strain and displacement fields assumed to be infinitesimal.
Moisture content and its influence on glued timber structures
Authors: Ermakov Valentin , Stepanova Ekaterina
Published: July 2020

The glued timber structure is well-known worldwide engineering product nowadays. Extensive knowledge of wood structure behavior has been as important basic to create new design projects. This paper presents the issue of determining moisture content (MC) in load-bearing glued wood structures, depending on a value of indoor relative humidity and temperature. There are two ways to study timber moisture content – calculation (manual or in programs) and measurement methods. this ways complement each other. Each of methods is more or less suitable for monitoring of structural elements or not suitable at all. Graphs, tables or 3D models of timber moisture content distribution in structure are can received using these methods. Two simple equations to determine timber moisture content are given in the paper. Besides, effect of timber moisture content on durability properties of wood structure is describes there.
Surface Rayleigh-Lamb waves in stratified substrate
Authors: Avershyeva Anna
Published: July 2020

Propagation of Rayleigh - Lamb waves has shortage of theoretical studies and demands in deeper analyses. Understanding the process of propagation of Rayleigh-Lamb waves depending on the geometrical and acoustical properties of the individual layers within the Earth’s crust is of great importance for the NDT of Earth exploration and development of seismic protection of buildings and structures. Propagation of these waves in the Earth’s crust upper layers is studied by analytical methods. A mathematical model for analyzing Rayleigh -Lamb waves propagating in stratified media is worked out. The analytical solution is constructed using Cauchy complex formalism and the method called Modified Transfer Matrix (MTM). As an example a multilayer system modeling the Earth’s crust, consisting of sedimentary rocks, a layer of granite, basalt and mantle, is considered. Equation for dispersion relations is derived. Fundamental modes of the dispersion curves for a stratified media are obtained.
Rapid reliability control of products in construction
Authors: Chiganova Nadezhda
Published: July 2020

The paper considers the method of rapid control of the reliability of construction products, based on the approximation of the mathematical expectation and variance of the process of changing the technical parameters of products over time by linear functions. When constructing the method of rapid reliability control in the normal mode, we will proceed only from an analysis of the external manifestation of the product wear process, that is, an analysis of the nature of the change in the technical parameters of the products over time. Therefore, we restrict ourselves to considering such methods of preliminary tests, which involve measuring the values of the technical parameters of each product of a sample of volume n at some points in time t. The order of preliminary studies and rapid control is considered as an example of a special case when the change in the technical parameters is approximated by a random process with a normal distribution density. A criterion is proposed by which at the stage of preliminary tests the question of the applicability of this control method to a specific type of product is solved. Formulas are found for calculating the characteristics of the rapid control plan for construction products for given risks of the supplier and customer.
Modeling the fracture behavior of Ultra - High Performance Fiber Reinforced Concrete slabs under contact Blast Loading
Authors: Hoa Pham Duy , Le Ba Danh , Thang Nguyen Cong , Tu Tran Huu
Published: July 2020

This paper presents a fracture behavior modeling of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) slabs under contact blast loading using the finite element method. The UHPFRC is supposed to be brittle material and follow the Johnson–Holmquist-II(JH-2) model. The steel rebar is modeled using the elasto-plastic model. The Emulsion Explosive has been used and modeled by the SPH method. UHPFRC slabs with the dimensions 1000mm of length, 800mm of width and 120mm of thickness is considered. The steel fibers with a volume fraction of 2% is used. The UHPFRC material is fabricated in laboratory using the material available in Vietnam. The concrete crater and spall damage of UHPFRC slab under contact blast loading are considered. The numerical results are compared with experiment. These results allow to evaluate the resistance against blast load of UHPFRC fabricated in lab.
Use of Reengineering in Construction
Authors: Sborshchikov Sergei , Lazareva Natalia , Kochenkova Elizaveta
Published: July 2020

The article discusses the use of the methodology of reengineering in the investment-construction. The goals, tasks, various options for their solution, application areas of reengineering in construction are identified, as well as its basic principles and development directions are formulated in the article. In this regard, it is assumed, that practical use of reengineering methodology will contribute to the creating of the comfortable and safe living environment, as well as competitive advantages of the building construction organizations, aimed at the reduction of cost and terms of works realization, increase of productivity and production quality. Works of foreign and domestic scientists are used as initial materials on the research issues, and functional and structural analysis are taken as cognition methods. In this regard, a retrospective of reengineering is investigated, a definition of this concept and its qualifications (“capital construction facility reengineering”, “business process reengineering”, “technological process reengineering”) are given, and directions for use in the investment-construction activities are established. At the corporate level, there are three types of reengineering: business processes, technological processes and capital construction facility. The article presents the distribution of these types of reengineering on the timeline of the investment-construction, as well as the distribution of participants by types of reengineering, the volumetric nature of reengineering is noted. It is shown, that a specific type of reengineering is the reengineering of territories and buildings and possible directions of its impulse are presented. Considering the sectoral level as the highest level in the hierarchy, the possible options for initiating reengineering “top-down” and “bottom-up” are established, and factors influencing this process are identified.
Management of the organization of production of building materials and products
Authors: Tikhonov Anatoly
Published: July 2020

the article describes the main stage of technological techniques and methods of automation of technological objects for the production of building products for the formation of structural schemes of organizational (manufacturing and implementation) control systems. A static characteristic of demand for construction products and a system of coordinated decision-making between the technical services of production and sales of products are developed. A generalized block diagram of the supply and demand management system for building materials and research is given. The functional dependence of the amount of profit on the quantity of produced building materials and products at the enterprises of the construction industry is formulated. Key words: production of building materials and products; management systems for the production and sale of building materials and products; demand, price and supply of products in the market; decision-making bodies of the organization of production and distribution of products; static characteristics of the demand for the product, its prices and profits from sales; feedback principle; adaptive (with fuzzy logic) control system; external disturbances; mismatch signals between supply and demand.
Management Model for Nuclear Power Station Project in Vietnam
Authors: Tuan Hai Dinh
Published: July 2020

Vietnam’s economy has been increasing quickly since 1986 to increase for several times. This leads to an increase in energy demands to satisfy for actual requests. To overcome future shortages of electricity, the Government of Vietnam has been preparing for its nuclear power plants during the past 20 years with many issues and matters must be considered seriously. One of them is which management model is mostly suitable and how to select best models. Good selection can help the Government of Vietnam goes straight forward to final completion of the project on time, cost and quality as well as specific requirements of safe issues, country security, economic enhancement, etc. This paper has an objective to discuss several common management models for construction projects applied in both Vietnam and the world. Later, it will propose a most suitable model of construction management for the first nuclear power plants in Vietnam. The Government of Vietnam can use in considering on its selection process of its nuclear power plants planned to build in the future.
Decision-making theory methods as a tool for choosing construction technology
Authors: Cherednichenko Nadezhda , Kuzmina Tatiana , Efimov Vladimir
Published: July 2020

The article discusses the problem of choosing the construction technology, which arises due to many factors. To find the optimal construction technology, it is proposed to divide the task into four stages. As a result, we come to the conclusion that it is necessary to consider this problem with the help of decision-making theory methods under conditions of uncertainty. Possible criteria for choosing the optimal construction technology are considered. The optimal production option is determined according to each criterion. Since each criterion has its own system for choosing the optimal construction technology, some sitework options do not fit on any of the criteria, therefore, according to the Paretto principle, these options can be discarded. Then, using linear convolution, one optimal construction technology is selected for each criterion. A tool for determination of the best construction technology using the methods of decision-making theory was obtained.
Efficiency of ultra-high-performance concrete applications on bridge construction
Authors: Binh Tran Duc , Tan Tran Van
Published: July 2020

Ultra-High-Performance Concrete (UHPC) is a new building material with many mechanical and technical features that are outstanding comparing with traditional concrete (Normal Concrete-NC). This has been proved by many studies in the world but mainly on technical point of view, and only a few researches have been mentioned the economic-technical efficiency of this new material. This study compared two alternatives of bridge design and execution, one using the UHPC girders and another using the NC girders, the case study of An Thuong Bridge project in Hung Yen city, Vietnam. The economic-technical efficiency of UHPC is considered in many aspects such as technical, economic, environmental and social aspects. Four research methods were used to assess the efficiencies of UHPC, the method using integrated criterion, estimation method, life-cycle cost, and life-cycle assessment method. Through expert surveys and analysis of each alternative design, the final result shows that using UHPC is more efficient than using NC. Indeed, the alternative using UHPC has a lower cost and less environmental impact than the NC alternative. However, these conclusions are only true in the case An Thuong Bridge project. For the other cases, the replacement of NC by UHPC should be considered according to particular situations before implementing it. This research is useful for bridge construction managers, construction material production enterprises, bridge construction investors, etc.
State Support of Building Complex through Mortgage Rate Reduction: Prospects and Risks
Authors: Kostrikin Pavel
Published: July 2020

In February 2020 the Russian government decided to develop public incentives for the mortgage rate reduction at least to 8%. What is the supposed economic effect of this decision? Can implementation of the new state program trigger another large-scale crisis on the market? The author makes an attempt to answer these extremely relevant questions by tapping into the experience of creation, development and a relatively recent failure of similar programs in the United States. The research done has revealed that the Russian government’s urge to harness the priming of economy through the support of mortgage lending, which was used in developed markets long ago, gradually gives rise to the same alarming symptoms that proved to be the forerunners of the world financial crisis in 2008-2009. Already available in Russia is an increasingly bulky and non-transparent system of mortgage loan securitization, a rapidly growing number of approved loans, mortgage rate reduction vigorously stimulated by the Russian government that brings about the gradual easing of claims on the quality of mortgage loans issued by retail banks in the backdrop of stiffening competition between banks and, as a consequence, the bank margin reduction. Thus all factors of the possible future collapse are on hand. The author comes to the conclusion that in order to prevent the situation getting out of control, the urgent development and adoption at the state level of scientifically grounded methodology is needed, whereby the development of real estate and contiguous sectors (banking infrastructure, in the first place) is to be put in sync with mechanisms of state support for the building complex.
Methods of computer modeling of cost models for buildings
Authors: Tyurin Ilya
Published: July 2020

The current methods of computer modeling of cost models created at the development stage of a building construction project are presented in the paper. The paper considers the world and Russian experience on the use of automation technologies in order to accelerate the formation of cost models for capital construction objects. The current approach to model formation is visualized, indicating the necessary components of the process.
Determining the Reasonable Degree of Specialization of Russian Companies Participating in NPP Construction Abroad
Authors: Grabovy Peter , Berezka Vitaly
Published: July 2020

NPP construction projects are distinguished by long construction periods (5-7 years), huge investments (up to 30 billion US dollars), and exposure to negative factors affecting the entire commissioning period and project cost. The complexity of the project management of such mega-project requires a set of special techniques and strong analytical and methodological support of decision-makers. The article discusses the practical aspects of identifying a reasonable degree of specialization of participating contractors. For an assessment of the contractor’s specialization level, the process specialization degree (DS
p
) indicator used. It describes the share of key types of works in their total volume, performed on their own. Construction company’s specialization considered as a vehicle ensuring the fullest application of state-of-the-art achievements of the construction science and technology in order to achieve the best technical and economic performance indicators of specialized entities, including improved labor productivity, reduced cost of works, maximized profit. The optimum specialization level and a degree in case of construction of major power complexes were assessed using the example of Belarus NPP chosen as a representative facility. The proposed approach to the determination of a reasonable degree of specialization allows construction entities to plan this parameter for short-term or long-term periods, to assess the economic efficiency of the specialization, subject to its increasing degree. As the achieving of the specialization degree is conditioned, the reasonable DS
p
delimitation is essential not only in economic but also in social terms. This article will be useful for the management of engineering, design, and contracting companies planning their participation (or already involved) in the investment and construction project in foreign countries.
Damage classification in concrete, mortar and cement-paste beams under bending by Acoustic Emission Technique (AET)
Authors: Nguyen-Tat Tam
Published: July 2020

In concrete, AET has been used to characterize the different fracture modes in flex-ural beams by RA method (described in RILEM TC 212 ACD recommendation). In this study, three-point-bending tests have been conducted on cement-based specimens (concrete, mortar and cement-paste) to promote tensile mode and/or shear mode in these specimens. Acoustic Emission (AE) raw data were filtered to remove noise from signals. Then, k-means algorithm, as a Pattern Recognition Analysis (PRA) method, was used to identify the similarities within the recorded signals and to classify the filtered-signals into groups. Clustering results by k-means according to a proposed process have proven efficiency in providing information on RA, AF, Rise-time, Duration and Absolute Energy (ABEN) related to mode I and mode II. Then, two damage classification techniques were used, in which RA method was applied to filtered signals. By these techniques, the proportion of mode I and II was specified and the location of demarcation line also fixed.
Optimal location of an intake at a reservoir prone to salt diffusion
Authors: Krutov Anatoly , Norkulov Bekhzod , Artikbekova Fotima , Nurmatov Panji
Published: July 2020

There are two main factors which prompt to look for an alternative to traditional approaches to the provision of drinking water. They are climate change and population growth.

Climate change and its increasing scale are no longer in doubt. It tends to increase the frequency and intensity of droughts. Changes in average water availability in most Central Asian river basins are estimated to be drastically big for the next 30 years. And, groundwater recharge may also be affected with a reduction in the availability of groundwater for drinking water in some regions.

Water use has been increasing worldwide by about 1% per year since the 1980s, driven by a combination of population growth, socio-economic development and changing consumption patterns. Global water demand is expected to continue increasing at a similar rate until 2050, accounting for an increase of 20 to 30% above the current level of water use, mainly due to rising demand in the industrial and domestic sectors.

These obliging to redefine the strategy for the use of water resources to ensure sustainable drinking water supply forcing the use of all available water resources even those that were not previously taken into account, for example, off stream storage reservoirs.

Research, development and innovation play an important role in supporting informed decision-making. Therefore, further scientific and engineering studies are also needed for the development of financially affordable, safe and efficient infrastructure services in the areas of drinking water supply, sanitation and hygiene and its components.

The article considers a particular reservoir the bottom of which is composed of saline soils operating in regular filling and emptying and subject to significant wind effects. The research conducted allowed to find a place of water intake location which provides a minimum salt content in the water abstracted.
Fundamentals of developing and designing portable weirs for farmlands
Authors: Choriev Jamshid , Muslimov Turavoy , Abduraupov Ramz , Khalimbetov Azat , Abdurakhmonov Sarvar
Published: July 2020

The article reveals the fundamentals of engineering and designing mobile weir with rectangular opening for farmlands, applicable for measuring discharge in interfarm and temporary canals. It includes the fundamentals of choosing most efficient structural solutions for the weir, choosing material for fabrication of its main elements, performing the static design for weir horizontal beams according to marginal states of providing reliability and stability of weir main elements. Results of calculations of diameter of steel bar for rectangular weir with B=25cm showed that the diameter needed is 6mm. The diameter is small enough for the weir to be called a thin plate weir. Thus, using 6mm bar is reasonable enough from the point of view of stability and the by the requirements for a thin plate weir.