Construction Material Engineering

WHAT CAUSES ROOFING GRANULES MINERAL BASE TO RUST AND METHODS FOR DETERMINING THE ROCKS RUST POTENTIAL

Vestnik MGSU 4/2018 Volume 13
  • Kochergin Aleksander Vladimirovich - OOO “Ural’skoe gorno-geologicheskoe agentstvo” Сandidate of Geological and Mineralogical Sciences, Chief Executive, OOO “Ural’skoe gorno-geologicheskoe agentstvo”, 20, office 102; Zavodskaya str., Ufa, 450045, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Almatov Aleksey Sergeevich - Moscow State University of Civil Engineering (National Research University) (MGSU) Postgraduate Student, Department of Technology of Knitting Substances and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), rsity of Civil Engineering (National Research University) (MGSU); This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Sokov Victor Nikolaevich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Professor of the Department of Cementing Substances and Concrete Technology, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 527-535

Pigment-coated mineral rocks are commonly used as color granules in roofing applications to provide aesthetic as well as protective functions to the asphalt shingles. Roofing granules typically comprise crushed and screened mineral materials, which are subsequently coated with a binder containing one or more coloring pigments, such as suitable metal oxides. Roofing granules are typically produced by mixing mineral particles with the coating materials in a drum or pan coater prior to drying or curing of the color coating in a kiln with extremely high temperature. In general, many rocks which are opaque, dense, and properly graded by screening for maximum coverage can be used conventionally in roofing granule process. Most stone sources have a small percentage of iron as a part of the stone’s chemical composition. For the most part the iron content is not encapsulated in the stone thus allowing for traces of rust to leach from the stone. Subject: The roof discoloration caused by the rust of the base rock is one of the reasons most serious customer complaints. The rust can appear during the curing process or throughout shingle lifetime weathering. The article seeks to answer the question what substance in a base rock can cause the rust and subsequent mineral degradation. Research objectives: discoloration, appearance of stains and streaks of rust on polymer-bitumen roofs is one of the most frequent causes of complaints from buyers. All this can be avoided by a deliberate choice of rocks, as a mineral carrier for the production of granules, that are not prone to “rust” and degradation. The reasons for the color change and the methods of choosing the rock least affected by this factor are described in this article. Materials and methods: The research has been done by comparing mineralogical and petrographic properties of granule base rocks and their color change values between calcined and incalcined granules. The rock samples underwent Differential thermal analysis in order to define a fraction of weak minerals in each of the rocks. Results: The study shows that all test samples changed its color after calcining at operation temperature 537°. Several minerals that change their colors and collapse during heating at operational temperature. Some of the mineral display rust, which is iron hydroxide. There are minerals with encapsulated iron that were stable during the calcining process and some collapsed and become sours of iron hydroxide leaching on the colored granules surface during the outdoor-weathering test. Conclusions: In the result of the study we can make a statement that the weakest minerals that collapses at operation temperature of the granule process and creates the iron hydroxides that can freely leak out of rock body are sulfides. It recommended to define the sulfides content in rock in order to prevent the rusting and breakdown issue.

DOI: 10.22227/1997-0935.2018.4.527-535

Download

TECHNICAL-ECONOMIC EFFICIENCY OF THE USE OF NANOMODIFIED FILLER FOR ASPHALT-CONCRETE

Vestnik MGSU 4/2018 Volume 13
  • Inozemtsev Sergey Sergeevich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Junior Researcher, “Nanomaterials and Nanotechnologies” Research and Education Center, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Korolev Evgeniy Valer’evich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Director of the “Nanomaterials and Nanotechnologies” Research and Education Center, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 536-443

Subject: technical and economic efficiency of the use of nanomodified porous mineral powder in the composition of asphalt-concrete mixture. The system of quality indicators of crushed stone-mastic asphalt-concretes obtained using nanomodified porous filler is presented. A general criterion for the quality of asphaltic concrete and a method for assessing the technical and economic efficiency of the use of nanomodified filler to control the properties of asphalt-concrete have been developed. Using the methods of system analysis, decomposition of the asphalt-concrete quality system was carried out and the basic quality indicators and dependencies for calculation of particular quality criteria were identified. The efficiency of using a filler based on a porous mineral material whose surface is modified with an additive based on iron hydroxide sol and silicic acid is shown. Research objectives: substantiation of effectiveness of the use of nanomodified porous mineral powder in the composition of asphalt-concrete mixture, taking into account the efficiency and cost criteria. Materials and methods: oil road bitumen BND 60/90, gabbro-diabase crushed stone of 5-20 mm fraction, granite crushing and screening products, stabilizing additive Viatop-66 and nanomodified diatomite were used. Samples of crushed stone-mastic asphalt-concrete were tested in accordance with the standard methods, and resistance to varying weather and climatic conditions and also rutting resistance were studied. Results: the proposed criteria allow one to estimate the effectiveness of the use of nanomodified mineral powder in asphalt-concrete, taking into account both the technical characteristics of the asphalt-concrete, obtained by using the powder, and the economic costs necessary to achieve improvement in quality indices. Concrete SMA-20, in which 100 % of the traditional filler is replaced by a powder based on diatomite, modified with iron (III) hydroxide sol and silicic acid, has a 28 % higher technical and economic efficiency compared to traditional crushed stone-mastic asphalt-concrete. This is achieved by significantly improving the quality of the material compared to the necessary ones. Conclusions: the use of the powder based on diatomite, modified with the iron (III) hydroxide sol, and silicic acid as a filler in the composition of asphalt-concrete mixture makes it possible to increase the asphalt-concrete efficiency index by 35 %. The increase in technical and economic efficiency by 28 % justifies application of the modified filler.

DOI: 10.22227/1997-0935.2018.4.536-543

Download

ANALYSIS OF APPEARANCE QUALITY OF SILICATE COATINGS BY ATOMIC FORCE MICROSCOPY METHOD

Vestnik MGSU 5/2018 Volume 13
  • Loganina Valentina Ivanovna - Penza State University of Architecture and Construction Doctor of Technical Sciences, Professor, Head of the Department of Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 G. Titova st., Penza, 440028, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Mazhitov Erkebulan Bisengalievich - Penza State University of Architecture and Construction Postgraduate Student, Department of Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 G.Titova st., Penza, 440028, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 599-608

Subject: studying surface quality of silicate coatings based on sol-silicate paints. Research objectives: study regularities in formation of the quality of appearance of silicate coatings, depending on the type of film-forming agent. Materials and methods: polysilicate solutions were prepared by interaction of stabilized solutions of colloidal silica (sols) with liquid glasses. Scanning probe microscopy methods were used to assess the quality of the coating surface. The parameters of surface roughness were determined. Results: it is shown that it is possible to improve the appearance of silicate coatings by using in paints the polysilicate solutions as a film-forming agent. It has been shown that for coating samples based on sodium and potassium polysilicate solution, the surface patches with a less pronounced relief are observed compared to the nature of microprofiles of the coating samples based on potassium and sodium liquid glass. Coatings based on potassium and sodium polysilicate solution are characterized by more uniform distribution of the surface roughness. Conclusions: sol-silicate paints are characterized by higher quality of appearance of the coatings.

DOI: 10.22227/1997-0935.2018.5.599-608

Download

INFLUENCE OF QUARTZ FLOUR ON TECHNOLOGICAL PROPERTIES OF SELF-COMPLETED CONCRETE MIXTURES

Vestnik MGSU 6/2018 Volume 13
  • Pustovgar Andrey Petrovich - Moscow State University of Civil Engineering (National Research University) (MGSU) candidate of technical sciences, assistant professor, Vice Rector for Research, scientific director of the Research Institute of Building Materials and Technologies (SRI SMiT), Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Ivanova Irina Sergeevna - Moscow State University of Civil Engineering (National Research University) (MGSU) research worker Research Institute of Building Materials and Technologies (SRI SMiT), Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Elenova Aurika Almazovna - Moscow State University of Civil Engineering (National Research University) (MGSU) candidate of technical sciences, head Research Laboratory of Building Composites, Solutions and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Abramova Anastasiya Yurʹevna - Moscow State University of Civil Engineering (National Research University) (MGSU) junior research worker of Research Institute of Building Materials and Technologies (SRI SMiT), Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Adamtsevich Aleksey Olegovich - Moscow State University of Civil Engineering (National Research University) (MGSU) candidate of technical sciences, senior research worker of Head of the Department of Scientific Policy, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 717-728

Subject: technological properties of self-compensating concrete mixtures with a fine-grained microfiller, represented by quartz flour. Objectives: to determine the quantitative parameters of the influence of the granulometric composition of quartz flour and its dosages on the workability and delamination of self-compacting concrete mixtures with a constant consumption of gauged water and various contents of the superplasticizing additive. Materials and methods: portland cement CЕМ II/A-S 42,5N was used in the work; natural pit sand of 0…5 mm fraction; crushed stone of fraction 5...20 mm; Silverbond quartz flour with an average particle size of 17 μm and 34 μm (grades 15 and 30, respectively); Superplasticizer based on polycarboxylate ester GLENIUM®115. The grain size composition of microfillers was investigated by laser diffractometry using the laser particle analyzer "Analysette 22" COMPACT in accordance with ISO 13320-1: 2009. The mobility of the cone flow diameter and the delamination of the concrete mixture were measured in accordance with GOST 10181. Results: it was researched the influence of quartz flour of various granulometric composition (with an average particle size of 17 μm and 34 μm), applied in dosages of 50, 100 and 150 kg/m3, on the technological properties of self-compacting concrete mixtures with different superplasticizer content (2, 4, 6 and 8 l/m3) and a constant flow of gauged water, as a result of which it has been established that the use of quartz flour of finer grinding provides higher values of SCC mobility under the condition of equal content of superplasticer and gauged water; when using a more coarse quartz flour, the growth of the dosage of the superplasticizer causes a more pronounced increase in the mobility of the concrete mixture; increasing the dosage of quartz flour allows to reduce the delamination of SCC. Conclusions: experimental studies have shown the effectiveness of the use of quartz flour for obtaining SCCs of various classes of workability (SF1 ... SF3) and resistance to delamination (SR1, SR2) and have established that the use of quartz flour D50 = 34 μm leads to insufficient optimization of the granulometric of the composition of the SCC and, as a consequence, stratification of the mixture with its low mobility, whereas the thinner fraction D50 = 17 μm, of the same type of microfiller, makes it possible to obtain resistant to the delamination of any SCC in for the workability due to varying dosages of both the microfiller and superplasticizer.

DOI: 10.22227/1997-0935.2018.6.717-728

Download

THE EFFECT OF TEMPERATURE DEPENDENCE OF THE SORPTION ISOTHERM AND MOISTURE CONDUCTIVITY COEFFICIENT ON THE MOISTURE TRANSFER IN THE WALL OF AERATED CONCRETE

Vestnik MGSU 6/2018 Volume 13
  • Zhukov Aleksandr Viktorovich - Tomsk State University of Architecture and Building (TSUAB) , Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya plaza, Tomsk, 634003, Russian Federation.
  • Tsvetkov Nikolay Aleksandrovich - Tomsk State University of Architecture and Building (TSUAB) , Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya plaza, Tomsk, 634003, Russian Federation.
  • Khutornoy Andrei Nikolaevich - Tomsk State University of Architecture and Building (TSUAB) , Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya plaza, Tomsk, 634003, Russian Federation.
  • Tolstykh Aleksandr Vital’evich - Tomsk State University of Architecture and Building (TSUAB) , Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya plaza, Tomsk, 634003, Russian Federation.

Pages 729-739

Subject: calculation of heat and moisture regimes of enclosing structures made of aerated concrete taking into account the transfer of liquid moisture, which is determined by the values of moisture transfer coefficients. The results of calculations of the thermal and moisture characteristics of walls made of aerated concrete, carried out with the use of generally accepted regulatory methods, require confirmation since a physically unacceptable result can be obtained. Research objectives: the goal of the study was to determine the effect of temperature dependence of the sorption isotherm and the moisture conductivity coefficient on the moisture transfer in the enclosing structures of aerated concrete. Materials and methods: numerical modeling of nonstationary heat and moisture transport processes in a flat homogeneous wall made of aerated concrete D400 for climatic conditions of Tomsk city was performed. The proposed model reflects the movement of moisture due to the gradient of partial pressure of water vapor for the entire range of values of relative humidity in air or moisture content in the material, and for large values of relative humidity - due to a gradient of moisture content. In the calculations, we took into account the dependence of sorption moisture not only on the relative humidity of air but also on its temperature. To determine the coefficient of moisture conductivity, we used an approximation formula constructed on the basis of known experimental data. Interpolation formulas are presented that reflect the change in temperature and humidity of the outside air in accordance with the data of the normative literature. Results: when carrying out special test calculations, it was established that moisture transfer through the inner surface of the wall is practically insensitive to the temperature dependence of the sorption isotherm and coefficient of moisture conductivity. The moisture flow through the outer surface is also not sensitive to the temperature dependencies of these parameters. However, the dependence calculated with allowance for the temperature in the sorption isotherm differs significantly from the dependence without taking temperature into account, and in addition, the position of a maximum of the average overall humidity is displaced from November to December. From the above analysis it follows that taking into account the temperature dependence of the coefficient of moisture conductivity does not lead to a significant change in the characteristics of moisture transfer, both at the stage of removal of construction-generated moisture and in the process of further operation. The temperature dependence of the sorption isotherm only affects the moisture content of the outer surface, but the discrepancy does not exceed 1 % in absolute value. Conclusions: the use of the sorption isotherm and the coefficient of moisture conductivity without taking into account their dependence on temperature is permissible for calculating the heat and moisture regime in homogeneous structures made of aerated concrete under conditions of sorption moistening or drying.

DOI: 10.22227/1997-0935.2018.6.729-739

Download

PROSPECTS FOR REINFORCED AUTOCLAVED CELLULAR CONCRETE PRODUCTION TECHNOLOGY

Vestnik MGSU 6/2018 Volume 13
  • Lobodenko Evgeniy Aleksandrovich - «Build Fast Technologies» Deputy Executive Director for Technical Development and Control, «Build Fast Technologies», 32 Gorkogo st., Elektrostal, Moscow region, 144002, Russian Federation.
  • Mikhailova Elena Vladimirovna - «Evonik Industries AG» Technical Support Manager, «Evonik Industries AG», «Evonik Industries AG», bldg. 5, 14 Kozhevnicheskaya st., Moscow, 115114, Russian Federation.
  • Gusev Konstantin Viktorovich - «Polykompozit» Head of Technology and Quality Department, «Polykompozit», 3 Novatorov st., Pskov, 180000, Russian Federation.

Pages 740-747

Subject: the research was carried out in the field of production of reinforced cellular concrete of autoclave hardening (aerated concrete). As initial data, we present joint experimental studies on selection of reinforcing material performed by the enterprises producing aerated concrete (town of Electrostal) and composite reinforcement (city of Pskov). Research objectives: the research task is reduced to selection of the material alternative to metal reinforcement, which will reduce the technological cycle of manufacturing of reinforced cellular concrete products, facilitate the structure’s weight reduction and increase the life cycle of the product. Materials and methods: we consider the use of composite reinforcement made with application of various hardeners (e.g., anhydride and aliphatic amine) that influence the behavior of the composite in a medium of autoclaved cellular concrete (ACC) (alkaline reaction medium, conditions of increased heat resistance). Results: the results of the performed studies showed the existence of the possibility of reinforcing element replacement in the production of autoclaved cellular aerated concrete. Conclusions: on the basis of the tests carried out, it was decided to continue laboratory studies for heat resistance of composite reinforcement with the use of amine hardener in a medium of autoclaved aerated concrete (AAC). It is also noted that this work was carried out for the first time, being valuable in improving the existing production technology of reinforced aerated concrete.

DOI: 10.22227/1997-0935.2018.6.740-747

Download

Design of non-rigid pavements in view of moving vehicles influence

Vestnik MGSU 8/2018 Volume 13
  • Kirillov Andrey M. - Automotive Road College candidate of physical and mathematical sciences, teacher of physics and astronomy, Automotive Road College, 26a/1 Yana Fabritsiusa st., Sochi, Krasnodar region, 354008, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 959-972

Subject: interaction of the moving vehicle with asphalt concrete road pavement. Research objectives: analysis of influence of dynamic loads from the moving vehicle on the road pavement with asphalt concrete. Materials and methods: interaction models are based on the impulse approach (impulse of dynamic loads) and dynamic factor. Results: creation of the mathematical model which is based on the impulse approach and allows us to determine the load on the pavement as a function of vehicle speed. Conclusions: 1) when the speed increases, the force exerted by the moving vehicle on pavement quickly decreases, reaching a minimum at some speed, and then slowly increases; 2) there exists the optimum vehicle speed for the highway exploitation, at which the impact of the force on the road is minimum; it is possible to increase the pavement longevity if this speed for road exploitation is complied with.

DOI: 10.22227/1997-0935.2018.8.959-972

Download

Investigation of rational types of light concrete for external walls in conditions of hot climate

Vestnik MGSU 10/2018 Volume 13
  • Hoshim R. Ruziev - Bukhara Engineering Technology Institute , Bukhara Engineering Technology Institute, 15 K. Murtazaev st., Bukhara, 200100, Uzbekistan.

Pages 1211-1219

Introduction. The paper presents theoretical and experimental studies of the improvement of the structure of lightweight concrete, which provides the maximum value of the attenuation of the amplitude of external air temperature fluctuations during the passage of heat flow through the walls and the reduction of thermal conductivity, the results of the 3-factor experiment on determining the rational structure of claydite concrete and the methods for their processing. To determine the purposeful structure of the composition of lightweight concrete and its thermal conductivity, a complex of research works was carried out at the Central Research Institute for Housing, applied to lightweight concrete for exterior walls. The main optimization criterion was the maximum reduction in thermal conductivity while providing the necessary strength, durability and waterproofness. The purpose of this work is theoretical research and experimental substantiation of methods for improving the structure of lightweight concrete used for a hot climate with improved functional performance. Materials and methods. As material a claydite gravel with bulk density p = 400 kg/m3 of Lianozovsky plant (Moscow) was used, at a ratio of 40 % of the fraction 5-10 mm and 60 % of the fraction 10-20 mm and a Portland cement of the brand “400” of the Voskresensky plant, not plasticized. The water flow rate was varied for 10 seconds, to ensure the mixture to be vibropacked.As a foam generating agent and plasticizer, the “Saponified wood resin” (SDO) was used in a 5 % aqueous solution. The methods were adopted in accordance with the Recommendation on the technology of factory production and quality control of lightweight concrete and large-panel constructions of residential buildings. M. CNIIEP dwelling, 1980. In the department of the lightweight concrete application at CNIIEP of dwelling, a method for the purposeful formation of the structure and composition of lightweight concrete, which provides a set of physic-technical, technological and technical-economic requirements, was developed. Results. Calculations are reduced to obtaining mathematical models of dependence of strength R, density ρ, thermai conductivity λ and other indicators of concrete characteristics from initial factors in the form of regression equations. Based on the equations obtained, it was possible to determine the expedient composition of lightweight concrete, which, in combination with the operational characteristics, provides comparable results of the technical and economic characteristics of a single-layer structure from the projected type of lightweight concrete. Conclusions. 1. An improved composition of the structural and heat insulating lightweight concrete for the load-bearing part of the structure, providing its high thermal stability by chemical additives and low consumption of porous sand, was developed. An algorithm for selecting its composition on computer is made. 2. The conducted researches in the field of design of external enclosing structures for hot climate conditions have shown that: single-layer exterior wall constructions with massiveness of D ≤ 4 provide minimum allowable values of heat flux attenuation and temperature fluctuation amplitude on the inner wall surface.

DOI: 10.22227/1997-0935.2018.10.1211-1219

Download

Evaluation of the influence of finishing coatings on the change of the moisture regime of the gaz-concrete fencing construction

Vestnik MGSU 11/2018 Volume 13
  • Loganina Valentina I. - Penza State University of Architecture and Construction Doctor of Technical Sciences, Professor, Head of Department of Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 Germana Titova st., Penza, 440028, Russian Federation.
  • Frolov Mikhail V. - Penza State University of Architecture and Construction graduate student of the Department of the Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 Germana Titova st., Penza, 440028, Russian Federation.
  • Skachkov Yuri P. - Penza State University of Architecture and Construction Doctor of Technical Sciences, Professor, Rector, Penza State University of Architecture and Construction, Penza State University of Architecture and Construction, 28 Germana Titova st., Penza, 440028, Russian Federation.

Pages 1349-1356

Introduction. Provides information about the moisture regime of the building structure of aerated concrete in the presence of finishing coatings. Plaster coatings based on dry construction mixtures Knauf Grunband, developed by the authors of lime compositions using hollow glass microspheres and ash aluminosilicate microspheres, cement-sand compositions were considered. Materials and methods. Aerated concrete blocks of various grades were used as the main material: D350, D400, D500, D600. Cement-slag plaster was adopted as an internal finishing layer for all variants. The outer surface of the wall is finished with Knauf Grunband dry construction mixtures, as well as developed lime compounds using hollow glass microspheres and ash aluminosilicate microspheres. The outside air temperature was determined, at which moisture condensation begins in the wall and on the border of the finishing layer - aerated concrete wall Results. When using Knauf Grunband plaster composition as finishing, the temperature of the onset of condensation drops to -9.0 °C. When using the developed DBM, obtained using hollow glass microspheres and ash aluminosilicate microspheres as fillers, the temperature of the onset of condensation decreases to -11.4 and -11.9 °С, respectively. Condensation at the border of the finishing coating - aerated concrete begins at a temperature of -2.4 °C, in a fencing structure of a gas concrete of the mark D400 with a plaster coating of a density of 1800 kg/m3 - at a temperature of -3.8 °C, and in aerated D400 grade with a plaster density of 1100 kg/m3 -at a temperature of -5.5 °C. Conclusions. The conducted studies prove that due to the use of heat-insulating DBM for finishing gas-concrete blocks of the D300-D600 grades, which allow to obtain coatings with a density of less than 800 kg/m3, the outdoor air temperature decreases, at which the moisture in the wall starts. Also, due to the use of the developed coatings, the external air temperature is significantly reduced, at which the finishing coating - aerated concrete begins at the border. This will minimize the amount of condensable moisture in the thickness of the enclosing structure and extend the service life of both the finishing coating and the wall as a whole.

DOI: 10.22227/1997-0935.2018.11.1349-1356

Download

Heuristic approach to solving two-criterion problem of optimization of composite materials

Vestnik MGSU 11/2018 Volume 13
  • Afonin Victor V. - National Research Ogarev Mordovia State University (MRSU) Candidate of Technical Science, Associate Professor, Associate Professor of Department of Automated Systems of Information Processing and Management, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Erofeeva Irina V. - Research Institute of Building Physics of the Russian Academy of Architecture and Building Sciences (NIISF RAASN) Junior Researcher, Research Institute of Building Physics, Research Institute of Building Physics of the Russian Academy of Architecture and Building Sciences (NIISF RAASN), 21 Locomotive travel, Moscow, 127238, Russian Federation.
  • Fedortsov Vladislav A. - National Research Ogarev Mordovia State University (MRSU) Postgraduate Student, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Emelyanov Denis V. - National Research Ogarev Mordovia State University (MRSU) Candidate of Technical Science, Associate Professor, Department of Building Materials and Technologies, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Podzhivotov Nikolay Y. - All-Russian Scientific Research Institute of Aviation Materials (VIAM) Candidate of Science (Technics), Senior Researcher, Laboratory of Strength and Reliability of Aircraft Materials, All-Russian Scientific Research Institute of Aviation Materials (VIAM), 17 Radio st., Moscow, 105055, Russian Federation.

Pages 1357-1366

Introduction. Presented the approach to optimal choice of materials, in particular, composite materials. An important task of modern materials science is the development of effective composite materials, which is associated with numerous scientific studies in this area and the search for materials with certain additives in order to obtain the necessary properties. First of all, it is an indicator of the hardness of the composite material. Materials and methods. Traditionally, different compositions are studied and property values are analyzed, and experimental results are processed in different ways. Multi-criteria optimization occupies a special place in the theory of optimization of objects, which include composite materials, in particular concrete with various additives. For this it is necessary to formulate a multicriteria optimality problem, in particular a two-criterion minimization problem. Results. Two heuristic optimization criteria are considered, according to which a vector criterion is formed, which allows to carry out the selection of composite materials from experimental data at its minimization. Vector criterion connects the change of the studied properties of the composite material with the simultaneous preference for the choice of the composition that optimizes the given criterion of optimality. The basis of the construction of the optimization scheme of choice of materials is a piecewise linear approximation of the test results, which allows to determine the scalar criteria on the basis of which the vector optimization criterion is constructed. To demonstrate two-criterion optimization, the results of experiments for cement composites exposed under the cyclic influence of negative and positive temperatures are considered. The search for the optimal composition in terms of hardness from the time of exposure. Conclusions. The proposed approach of optimal choice of materials, in particular, composite materials, can be tested on large numbers of test samples, or to automate calculations. This approach has a certain heuristic character. But its practical significance is confirmed by the expert evaluation of the quality of composite materials due to the existing methods of evaluation of materials, for example, in terms of changes in its hardness.

DOI: 10.22227/1997-0935.2018.11.1357-1366

Download

Stress-strain state of fiberglass in conditions of climatic aging

Vestnik MGSU 12/2018 Volume 13
  • Martynov Gleb V. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Monastyreva Daria E. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Morina Elena A. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Makarov Aleksey I. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.

Pages 1509-1523

Introduction. Were investigated samples of fiberglass with the aim of its effective use in construction in the long term. Fiberglass is considered one of the most versatile and durable materials among polymer composite materials, however, and it is subject to destruction. It is known that one of the main reasons for reducing the specified characteristics and material properties is operational. At the design stage, it is necessary to determine the most reliable and economical materials used and, accordingly, be sufficiently aware of their strength and durability. Thus, in order to avoid the destruction of the material, as well as significantly enhance and prolong its service life, it is necessary to be aware of how exactly the properties of the material change over time. Regarding reinforced concrete, wood, brick and steel fiberglass is used in construction recently. This means that while the service life of the list of the most common materials in construction is known to a sufficient extent, manufacturers do not dare to use fiberglass as a material for critical structures. This occurs because changes in its characteristics, depending on operational factors, are not sufficiently studied for intervals exceeding 4-5 years of operation. Materials and methods. During the work, samples of fiberglass SPPS with a longitudinal and transverse arrangement of fiberglass were tested for climatic aging in a climatic chamber for 5 cycles simulating 5 years of material operation. All samples were subjected to tensile testing on a tensile testing machine R-5. Results. Destructive stresses were determined, calculations were carried out and elastic and strength characteristics of the samples were analyzed. On the basis of the obtained results, an analysis was carried out, conclusions were formulated about the use of fiberglass in the construction in the long term, as well as the influence of such operational factors as moisture, positive and negative temperatures, and ultraviolet radiation on the properties of fiberglass with a different arrangement of fiberglass. Conclusions. Found that the destructive stresses of fiberglass are significantly reduced during the first two years of operation, which must be considered when choosing fiberglass with the stated characteristics. Ultraviolet does not have a significant effect on the elastic-strength properties of the material, while during operat

DOI: 10.22227/1997-0935.2018.12.1509-1523

Download

Modifying epoxy polymers by cyclic carbonates of epoxidated plant oils

Vestnik MGSU 12/2018 Volume 13
  • Gotlib Еlena M - Kazan National Research Technological University (KNRTU) Doctor of Engineering, Professor, Professor of the chair of artificial rubber technology, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.
  • Anh Nguyen - Kazan National Research Technological University (KNRTU) postgraduate student of the chair of artificial rubber technology, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.
  • Sokolova Аlla G. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of foreign languages and professional languages Department, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 1491-1498

Introduction. Application of renewable raw materials for manufacturing non-toxic components of polymer materials is of great practical interest. Cyclic carbonates on the base of epoxidated rubber tree oil could be seen as a promising alternative of fossil fuels. The ability of compounds containing cyclic carbonates to interact with primary amines and to form urethane and hydroxyl groups makes them rather efficient modifiers of amine-toughened epoxy compounds on the base of low-molecular diane oligomers. Introduction of cyclic carbonates enhances impact behavior of epoxy materials as well as their adhesion and strength properties. Materials and methods. Epoxy resin ED-20 was used for the research, as a cross-linking agent for cold toughening aminealkylphenol AF-2 was used; cyclic carbonates of epoxidated soy oils and rubber tree oil were applied as modifiers. Adhesional strength of bond joints has been determined in compliance with the GOST 28840-90, abrasive hardness of epoxy compound samples has been tested by the vertical optical caliper IZV-1. Results. When applying two-stage technology for obtaining epoxy cyclic carbonate compounds, there has been appeared a significant increase of adhesion to aluminum. This effect could be even more noticeable with increasing temperature during the stage of mixture of the amine toughener with the cyclic carbonate modifier. High viscosity of cyclic carbonate modifiers complicates the process of mixing components of the epoxy compound and correspondingly its application as a backing of glues and linings. The authors researched cyclic carbonates of epoxidated soy oil with various averaged functionality as modifiers. Application of epoxy materials CESO-75 as a modifier has proven to be more forward-thinking for the reasons of cost-efficiency and for operating and technological properties. CESO lowers the coefficient of static friction for epoxy materials together with enhancing their abrasion hardness. Conclusions. Cyclic carbonates of epoxidated plant oils (soy oil and rubber tree oil) as rather efficient non-toxic modifiers of epoxy polymers are of practical interest. They are produced on the base of annually renewable plant raw materials. Their application enables to enhance abrasion hardness and adhesion properties of epoxy compounds and also improve their antifriction properties.

DOI: 10.22227/1997-0935.2018.12.1491-1498

Download

EFINITION OF DEFORMATION OF FINE-GRAINED CONCRETE ON THE BASIS OF SULPHATE-RESISTANT PORTLAND CEMENT

Vestnik MGSU 12/2018 Volume 13
  • Ngo Xuan Hung - Moscow State University of Civil Engineering (National Research University) (MGSU) postgraduate student of Department of Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Tang Van Lam - Moscow State University of Civil Engineering (National Research University) (MGSU) postgraduate student of Department of Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Bulgakov Boris I. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of Department of Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Aleksandrova Olga V. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of Department of Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Larsen Oksana A. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of Department of Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 1499-1508

Introduction. The possibility of determining the relative deformations of fine-grained concretes based on sulfate-resistant cement was formulated by testing samples of gypsum-cement-sand mixture in distilled water in accordance with the requirements of the Vietnamese standard TCVN 6068:2004. Objective - to determine the deformations of fine-grained concrete because of sulfate-resistant Portland cement in accordance with the requirements of the TCVN 6068:2004 standard to assess its resistance to corrosion in an aggressive sulfate medium. Materials and methods. To obtain a gypsum-cement-sand mixture, a finely disintegrating binder was used, consisting of sulfate-resistant Portland cement of the type CEM I CC 42.5 N produced by the “Tam Diep” plant with the addition of natural gypsum produced by the company “Dinh Vu”. Quartz sand was used as fine aggregate. All raw materials used were native to Vietnam. Grinding fineness, normal cement density, setting time, the uniformity of the volume change and the activity of sulfate-resistant Portland cement were determined according to GOST 30744-2001; deformations of samples from gypsum-cement-sand mixtures - according to the Vietnamese standard TCVN 6068:2004. Results. Investigated the relative increase in the volume of samples of gypsum-cement-sand mixture based on sulfate-resistant Portland cement and natural gypsum as a result of their testing in distilled water according to the standard TCVN 6068:2004. Conclusions. Found that the average value of the relative deformation of the prism samples of concrete as a result of a 14-day test in distilled water was 0.037 %, which is within the acceptable value of 0.04 % in accordance with the requirements of the Vietnamese standard TCVN 6067:2004. Therefore, sulfate-resistant Portland cement type CEM I CC 42.5 N produced by the “Tam Diep” plant is a promising material as a binder for the preparation of corrosion-resistant concrete. The increase in the mean values of the relative deformations of the gypsum-cement-sand prism specimens after the 28-day and 60-day of testing, compared to the results of the 14-day test, can be explained by a slightly increased content of tricalcium aluminate in the studied cement.

DOI: 10.22227/1997-0935.2018.12.1499-1508

Download

Effect of quartz powder and mineral admixtures on the properties of high-performance concrete

Vestnik MGSU 1/2019 Volume 14
  • Nguyen Duc Vinh Quang - Moscow State University of Civil Engineering (National Research University) (MGSU) Postgraduate student of Department of Technologies of Cohesive Materials and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Bazhenov Yuriy M. - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Head of the Department of Technologies of Cohesive Materials and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Aleksandrova Olga V. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of Department of Technologies of Cohesive Materials and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 102-117

Introduction. This study focuses on the use of silica fume partially replacing cement with 0, 5, 7.5, 10, 12.5 and 30 % constant replacement of fly ash by weight of cement in concrete. Concrete is probably the most extensively used construction material in the world. But the conventional concrete is losing its uses with time and high-performance concrete (HPC) is taking that place. HPC has superior mechanical properties and durability to normal strength concrete. Because of, the microstructure of HPC is more homogeneous than that of normal concrete (NC) due to the physical and chemical contribution of the mineral admixtures as well as it is less porous due to reduced w/c ratio with the addition of a superplasticizer. The inclusion of additives helped in improving the properties of concrete mixes due to the additional reduction in porosity of cement paste and improving the particle packing in the interfacial transition zone (between cement paste and the aggregates).In this experimental investigation the behavior of HPC with silica fume and fly ash with and without quartz powder were studied. The water-binder ratio was kept 0.3 and 20 % quartz flour as partial replacement of fine aggregate for all cases. Materials and methods. Used materials in Vietnam, as follow, Sulfate-resisting Portland cement - PCSR40 (type V) of company Luks Cement (Vietnam) Limited was used in the work. Crushed granite of fraction 9.5…20 mm - as coarse aggregate, Natural sand from Huong river of 0.15…2.5 mm fraction with the fineness modulus of about 3.0 and quartz powder with an average particle size of 5…10 μm were used as fillers; Sika® Viscocrete®-151 is a superplasticizer based on a blend of 3rd generation PCE polymers was used as a plasticizing admixture. The flg ash from Pha Lai thermal power plant and Sika silica Sikacrete® PP1 (particle size < 0.1 μm) was used as a mineral active admixture. The study of strength and technological properties of high-performance concrete was performed by using standard methods. Results. Established by icate that, the workability and strength increase at a certain level and after that, they decline with further increase in the replacement level of silica fume is 12.5 %, on the basis of 30 % FA replacement, the incorporation of 10 % SF showed equivalent or higher mechanical properties and durability compared to the reference samples. Conclusions. HPC consists of mineral admixtures such as silica fume and fly ash use combine quartz powder and superplasticizer helped in improving the strength and durability of concrete mixes due to the additional reduction in porosity of cement paste and an improved interface between it and the aggregate. With 30 % fly ash is optimum dosage used to replacement of cement, incorporation 10 % SF (by weight) and combine of partial replacement of fine aggregate by 20 % quartz powder. On the other hand, a few mathematical equations can be used to derive the durability properties of concrete based on its compressive strength.

DOI: 10.22227/1997-0935.2019.1.102-117

Download

Regularities of formation of adhesive contact “sol-silicate paint - substrate”

Vestnik MGSU 1/2019 Volume 14
  • Loganina Valentina I. - Penza State University of Architecture and Construction Doctor of Technical Sciences, Professor, Head of Department of Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 Germana Titova st., Penza, 440028, Russian Federation.
  • Mazhitov Erkebulan B. - Penza State University of Architecture and Construction postgraduate student of the Department of Quality Management and Technology of Construction Production, Penza State University of Architecture and Construction, 28 Germana Titova st., Penza, 440028, Russian Federation.

Pages 94-101

Introduction. The use as a binder in the manufacture of silicate paints polysilicate solutions obtained by mixing liquid glass and silica sol is considered. To regulate the rheological properties of the paint, improve the filling and prevent the pigment part from sagging, it has been proposed to introduce glycerin into the binder composition. The results of studying the interfacial interaction between the paint and the substrate are given. Materials and methods. In developing the formulation of silicate paints based on polysilicate solutions, MK-2 microcalcite, marshalite, diatomite and talc of MT-GSM grade were used as a filler, and titanium dioxide as a pigment. Polysilicate solutions were obtained by reacting stabilized solutions of colloidal silica (sols) with aqueous solutions of alkali silicates (liquid glasses). Nanosil 20 and Nanosil 30 silicic acid sol were used, produced by the Promsteklocentr PC. Used potassium liquid glass with module M = 3.29. A thermodynamic method was used to assess the interfacial interaction. Results. Shown that the introduction of glycerol into the formulation of a sol of silicate paint promotes a decrease in the interfacial surface tension and a better wetting of the surface of the mortar substrate. An increase in wetting coefficient is observed. Coatings based on sol silicate paints with the addition of glycerin are characterized by increased crack resistance. An increase in tensile strength, maximum tensile properties, and decrease in the elastic modulus of paint membranes based on the composition with glycerol has been established. The values of the free surface energy of the coating based on the sol of silicate paint and the ratio of the polar to the dispersion component of the free energy of the surface are given. Coatings based on sol of silicate paint with the addition of glycerin are characterized by a large value of the free energy of the surface. In the process of moistening a decrease in the free surface energy is observed due to a decrease in the dispersion component. Conclusions. Studies have shown that the introduction of an additive of glycerin in the formulation of a silicate paint sol contributes to an increase in the performance properties of coatings based on it.

DOI: 10.22227/1997-0935.2019.1.94-101

Download

Stress-strain state of friction joints with laser treatment of contact surfaces

Vestnik MGSU 1/2019 Volume 14
  • Gleb V Martynov - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Monastyreva Daria E. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Makarov Aleksey I. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.
  • Morina Elena A. - Peter the Great St. Petersburg Polytechnic University (SPbPU) undergraduate student, Peter the Great St. Petersburg Polytechnic University (SPbPU), 29 Polytechnicheskaya st., St. Petersburg, 195251, Russian Federation.

Pages 72-82

Introduction. Researched is conducted to determine the possibility of using an alternative method - laser cleaning. Laser systems have proven themselves in many areas and are a high-tech and effective solution for many construction problems. Despite this nowadays sandblasting is the most common method of processing contact surfaces of high-strength bolted joints - an outdated technology, with high equipment wear and even dangerous to people’s health. Materials and methods. Sandblast and laser-treated specimens were tested for shear. Before testing, the roughness of the contact surfaces and the tension force of high-strength bolts were tested. During the test, the readings of the meter and dial-indicator were taken. The experiments were carried out on a hydraulic press IPS-500, the samples were provided in a processed form. Results. According to the data obtained, strain graphs were plotted and the shear forces of the samples were calculated. Calculated efforts were compared with standard values. The results show the compliance of samples with the requirements of SP 35.13330.2016 “Bridges and pipes” in terms of strength characteristics. Samples with laser surface cleaning have a safety margin value similar to sandblasted samples. Conclusions. Comparison of the strength characteristics proves the possibility of using laser cleaning of the contact surfaces of friction joints. After the transition from outdated technologies, the process of surface preparation can be made economical and environmentally friendly. The obtained values and data can be entered into a number of regulatory documents, including SP 35.13330.2016 “Bridges and pipes” for future research and the widespread application of the method.

DOI: 10.22227/1997-0935.2019.1.72-82

Download

Reference image quality assessment of composite materials exposed to positive and negative temperatures

Vestnik MGSU 1/2019 Volume 14
  • Afonin Victor V. - National Research Ogarev Mordovia State University (MRSU) Candidate of Technical Science, Associate Professor, Associate Professor of Department of Automated Systems of Information Processing and Management, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Erofeeva Irina V. - Research Institute of Building Physics of the Russian Academy of Architecture and Building Sciences (NIISF RAASN) Junior Researcher, Research Institute of Building Physics, Research Institute of Building Physics of the Russian Academy of Architecture and Building Sciences (NIISF RAASN), 21 Locomotive travel, Moscow, 127238, Russian Federation.
  • Zotkina Marina M. - National Research Ogarev Mordovia State University (MRSU) Candidate of Technical Science, Associate Professor, Department of Building Materials and Technologies, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Emelyanov Denis V. - National Research Ogarev Mordovia State University (MRSU) Candidate of Technical Science, Associate Professor, Department of Building Materials and Technologies, National Research Ogarev Mordovia State University (MRSU), 68 Bolshevistskaya st., Saransk, 430005, Russian Federation.
  • Podzhivotov Nikolay Yu. - All-Russian Scientific Research Institute of Aviation Materials (VIAM) Candidate of Technical Science, Senior Researcher, Laboratory of Strength and Reliability of Aircraft Materials, All-Russian Scientific Research Institute of Aviation Materials (VIAM), 17 Radio st., Moscow, 105055, Russian Federation.

Pages 83-93

ABSTRACT Introduction. The question of a comparative assessment of the quality of images obtained as a result of scanning test composite materials exposed under the cyclic effects of positive and negative temperatures is considered. The samples are sorted relative to the reference numerical metric expressed as a percentage. Materials and methods. The compared composites differ in composition relative to the control sample. Periodic scanning of the tested composites is carried out during several control points of time. A comparative analysis of the image quality of test composites was carried out both during the entire exposure time and at the control points of time. On the basis of the existing algorithm Structural Similarity Index for measuring image quality (SSIM), percentage indicators of sample quality were determined depending on the composition and exposure time. The results obtained allow the selection of composite materials in accordance with the level of structural similarity in structural color characteristics. According to the SSIM algorithm, the resulting metric values are in the range [-1; +1]. Full structural similarity corresponds to a value equal to one. It is proposed to express the SSIM metric as a percentage with the transformation that the change in the color structural difference of the relative control sample can vary from zero to 100 %. Results. For the proposed method of comparing images of scanned samples of composite materials, ten samples of composite materials of different composition were used. Numerical results of the experiment with their graphical visualization give a clear idea of the nature of the change in color characteristics relative to the control sample. Consistent evaluation at the exposure points shows the nature of changes in the properties of materials from the duration of exposure to cyclic changes in positive and negative temperatures. Conclusions. The proposed benchmark image quality assessment based on the existing SSIM algorithm allows you to quickly investigate groups of materials, the change in properties of which is caused by their exposure in adverse operating conditions.

DOI: 10.22227/1997-0935.2019.1.83-93

Download

The influence of plasticizers on the properties of gypsum binders activated in vortex layer apparatus

Vestnik MGSU 3/2019 Volume 14
  • Ibragimov Ruslan A. - Kazan State University of Architecture and Engineering (KSUAE) Candidate of Technical Sciences, Associate Professor, Head of the Department of Technology of building processes, Kazan State University of Architecture and Engineering (KSUAE), 1 Zelenaya st., Kazan, 420043, Russian Federation.
  • Korolev Evgeny V. - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Vice rector, Moscow State University of Civil Engineering (National Research University) (MGSU), 6 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Deberdeev Timur R. - Kazan National Research Technological University (KNRTU) Doctor of Technical Sciences, Professor, Head of the Department of Technologies for processing polymers and composite materials, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.

Pages 293-300

Introduction. The article presents the results of a study to determine the influence of introduction method, type and concentration of plasticizing additives on the structure parameters and properties of gypsum stone obtained using gypsum cement treated in a vortex layer apparatus. Materials and methods. The G-5 BII gypsum cement was used for the investigation. The physicomechanical properties of the gypsum stone were determined in accordance with standard procedures, specific surface area was determined by air permeability, X-ray patterns were taken by means of the D2 Phaser diffractometer. Results. The data were obtained from 11 compositions of gypsum binder processed in the vortex layer apparatus and compared with a reference composition in the sense of the specific surface of the binder, mineralogical composition and physicomechanical characteristics of the gypsum stone. Conclusions. As a result of the investigation, it was revealed that the processing of the gypsum binder in the vortex layer apparatus leads to an increase in the specific surface up to 2 times. Modification of gypsum with MF superplasticizer significantly increases the ultimate compression strength (by 323 %) and bending strength (by 218 %) of the gypsum stone, as compared with the initial composition. Meanwhile the combined activation of gypsum with superplasticizers leads to a sharp decrease in strength and a significant slowdown in hydration. The greatest increase in the strength of the gypsum stone is observed when modifying activated gypsum. So, depending on the type of superplasticizer, the compression strength increases by 100 to 302 %, and bending strength by 86 to 218 %. Also this significantly reduces the gypsum stone overall porosity (down to 23 %) and softening coefficient (down to 51%).

DOI: 10.22227/1997-0935.2019.3.293-300

Download

Improvement of methods for determining power and energy characteristics of fibre-reinforced concrete crack resistance

Vestnik MGSU 3/2019 Volume 14
  • Pukharenko Yuri V. - Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU) Doctor of Technical Sciences, Professor, Head of the Department of Building Materials Technology and Metrology, Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU), 4 2nd Krasnoarmeyskaya st., Saint Petersburg, 190005, Russian Federation.
  • Zhavoronkov Mikhail I. - Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU) Assistant of Department of Building Materials Technology and Metrology, Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU), 4 2nd Krasnoarmeyskaya st., Saint Petersburg, 190005, Russian Federation.
  • Panteleev Dmitry A. - Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU) Candidate of Technical Sciences, Associate Professor of Department of Building Materials Technology and Metrology, Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU), 4 2nd Krasnoarmeyskaya st., Saint Petersburg, 190005, Russian Federation.

Pages 301-310

Introduction. The actual problem of improving the methods of experimental studies of the properties of fibre-reinforced concrete obtained using various types of fibre is considered in the article. As a result of the analysis of the technical literature, some shortcomings of the existing test methods of one of the most important characteristics of fibre-reinforced concrete, crack resistance, were revealed. The aim of this study is to develop methods for determining the fibre-reinforced concrete crack resistance parameters. Materials and methods. The GOST 29167 standard is used as a basis for the development of a new method and device. Regulations of this standard pursue an aim of obtaining the most informative data about the material by plotting the dependences of test specimen deflections on the applied loads and determining with their assistance the power and energy parameters of the crack resistance. The test samples are presented by fibre-reinforced fine concrete beams made using steel wire fibre of circular cross-section and wave profile. Diagrams of the dependences of sample deflections on applied loads were plotted in the course of the tests for tension in bending. Calculations of power and energy parameters of crack resistance were conducted. Results. The device and method of testing the fibre-reinforced concrete crack resistance are developed and proved. A comparative analysis of the results of tests of steel fibre concrete samples is made. Conclusions. The proposed device and method allow researching influence of the fibre reinforcement parameters on fibre-reinforced concrete crack resistance parameters quickly and with minimal labour expenditures for preparation and tests. Increased adequacy of the obtained data promotes building up new trends in research and rapid introduction of fibre-reinforced concrete in the construction industry. As a result of the analysis of the obtained data, it is established that the proposed device and method can be recommended for research of the influence of fibrous reinforcement parameters on the obtained fibre-reinforced concrete properties and accumulation of statistical data for the development and improvement of normative and technical documents.

DOI: 10.22227/1997-0935.2019.3.301-310

Download

Epoxy antifriction wollastonite-filled materials

Vestnik MGSU 3/2019 Volume 14
  • Gotlib Elena M. - Kazan National Research Technological University (KNRTU) Doctor of Technical Sciences, Professor, Professor Technology of synthetic rubber, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.
  • Khasanova Аlmira R. - Kazan National Research Technological University (KNRTU) assistant of the Department of materials science, welding and industrial safety, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.
  • Galimov Engel R. - Kazan National Research Technological University (KNRTU) Doctor of Technical Sciences, Professor, Head of the department of materials science, welding and industrial safety, Kazan National Research Technological University (KNRTU), 68 Karl Marx st., Kazan, 420015, Russian Federation.
  • Sokolova Аlla G. - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Associate Professor of foreign languages and professional languages Department, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 311-321

Introduction. Domestic mineral natural-origin filler ‘wollastonite’, also known as calcium methyl silicate, is widely used as a base for wear-resisting epoxy antifriction materials. Due to anisodiametric shape of its particles, wollastonite functions as a micro reinforcement fibre enhancing adhesion strength and wear resistance of epoxy compositions, improving their antifriction properties, especially when organomodifying by quaternary ammonium salts. In this regard, the investigation of the impact of chemical composition of such surfactants as quaternary ammonium salts on the properties of epoxy compound materials presents utmost interest for researchers developing low-friction materials. Materials and methods. Epoxy diane resin ED-20 was hardened with aminoalkylphenol AF-2. Content of epoxy hardener was determined by equimolar ratio of epoxy groups to amine groups. Domestic wollastonite of the grade Miwoll 10-97 was used as filler, particle length to the diameter correlated as 15:1. The wollastonite surface was activated with surfactants belonging to domestically produced quaternary ammonium salts. Wear resistance of specimens was tested by means of the vertical optical caliper IZV-1. Friction coefficient was estimated with the assistance of the computer-automated frictional machine CSM Instruments Tribometer. Adhesion strength of glue joint was determined as per GOST 28840-90 standard. Two bars of sheet aluminium were used as glued surfaces as per GOST 14759-69 standard. Results. Reduction of wear of epoxy coatings when modified with micro reinforcing wollastonite can be explained by the increase of cross-linking degree of the polymer. The length of alkyl radical of quaternary ammonium salts used for wollastonite surface activation affects the intervals between the epoxy links. As the quaternary ammonium salt chain length is growing, wear of epoxy materials is reducing. Introduction of the wollastonite containing metallic oxides in the epoxy composites increases wear resistance and adhesion strength and reduces coating friction coefficients. Conclusions. Hardened with the AF-2 and filled with the wollastonite of the Miwoll 10-97 grade, the epoxy compound materials have enhanced wear resistance and adhesion strength and lower friction coefficient. The best result is observed when applying wollastonite modified with a surfactant belonging to the class of quaternary ammonium salts. The wollastonite can be used for practical purposes as a perspective reinforcing agent for epoxy materials with improved wear resistance, enhanced adhesion to metals and reduced friction coefficient.

DOI: 10.22227/1997-0935.2019.3.311-321

Download

Results 1 - 20 of 21
  • «
  •  Start 
  •  Prev 
  •  1 
  •  2 
  •  Next 
  •  End 
  • »