The article discusses the results of investigations on the influence of the stress state of concrete on its frost resistance. Particular attention is paid to the effect of low negative temperatures (up to minus 70^oC) on the parametric levels of the stress-strain state areas during axial compression of structural heavy and light concretes of B30 and B40 compressive strength classes, in particular, on the lower (R⁰_T) and upper (R^ν_T) boundaries of the microcracking areas of these concretes. An assessment of the degree of influence on this process of the structural and technological characteristics of concrete was made. The results obtained can be used in the practice of reinforced concrete structures designing that will be operated in the harsh climate of the North-Eastern regions of Russia, the Far North and the coast of the Arctic shelf of the country.

V.N. YARMAKOVSKY, Candidate of Sciences (Engineering), Chief Researcher, Honorary Member of the Russian Academy of Architecture and Construction Sciences, Expert of the Russian Academy of Sciences, member of the International Federation for Structural Concrete (fib) (This email address is being protected from spambots. You need JavaScript enabled to view it.)
D.Z. KADIEV, Junior Researcher (This email address is being protected from spambots. You need JavaScript enabled to view it.)

Research Institute of Building Physics RAACS (21, Lokomotivny Proezd, Moscow, 127238, Russian Federation)

1. Moskvin V.M., Ivanov F.M., Alekseev S.N., Guzeev E.A. Korroziya betona i zhelezobetona, metody ikh zashchity [Corrosion of concrete and reinforced concrete, methods of their protection]. Moscow: Stroyizdat. 1980. 536 p.
2. Moskvin V.M., Savitskii A.N., Yarmakovskii V.M. Betony dlya stroitel’stva v surovykh klimaticheskikh usloviyakh [Concrete for construction in harsh climatic conditions]. Leningrad: Stroyizdat. 1973. 169 p.
3. Gorchakov G.I., Kapkin M.M., Skramtaev B.G. Povyshenie morozostoikosti betona v konstruktsiyakh promyshlennykh i gidrotekhnicheskikh sooruzhenii [Increasing the frost resistance of concrete in the structures of industrial and hydraulic structures]. Moscow: Stroyizdat. 1965. 270 p.
4. Berg O.Ya. On the limiting state of reinforced concrete structures for the durability of concrete. Beton i Zhelezobeton [Concrete and Reinforced Concrete]. 1964. No. 11, pp. 4–10.
5. Berg O.Ya., Shcherbakov E.N., Pisanko G.N. Vysokoprochnyi beton [High strength concrete]. Moscow: Stroyizdat. 1971. 208 p.
6. Guzeev E.A., Leonovich S.N., Piradov K.A. Mekhanika razrusheniya betona: voprosy teorii i praktiki [Fracture Mechanics of Concrete]. Brest: BPI. 1999. 215 p.
7. Zaitsev Yu.V., Leonovich S.N. Prochnost’ i dolgovechnost’ konstruktsionnykh materialov s treshchinoi [Strength and durability of structural materials with a crack]. Minsk: BNTU. 2010. 362 p.
8. Hsu T.C., Slate F.O., Sturman G.M., Winter G. Microcracking of plain concrete and the shape of stress-stain curve. JACI. 1963. Vol. 60. No. 2.
9. Shah S.P., Chandra S. Critical stress, volume change and microcracking of concrete. JACI. 1963. Vol. 65. No. 9.
10. Yarmakovskiy V.N. On the calculation method for reinforced concrete structures with increased frost resistance. Collection of Proceedings of NIIZHB «Improving the resistance of concrete and reinforced concrete under the influence of aggressive environments» edited by Professor V.M. Moskvin. Moscow: Stroyizdat. 1975, pp. 34–38. (In Russian).
11. Yarmakovskiy V.N., Karpenko N.I. Features of technology, structure and mechanics of high-strength structural lightweight concrete for marine hydraulic structures in the conditions of the Arctic continental shelf. Proceedings of the International Conference «Polar Mechanics-2016». Vladivostok. 2016, pp. 24–32. (In Russian).
12. Patent RF 2087438. Ustanovka dlya proizvodstva osteklovannogo poristogo graviya [Installation for the production of vitrified porous gravel]. Panchenko V.F., Frantsenyuk I.V., Denisov G.A., Shkolnik Ya.Sh., Yarmakovskiy V.N., Kadantsev N.V., Korotaev A.S. Declared. 26.06.1996. (In Russian).
13. Iarmakovski V.N. New types of the porous slag aggregates and lightweight concretes and their application. International Symposium on Structural Lightweight Aggregate Concrete. June 1995. Proceedings edited by Ivar Holland. Sandefjord. Norway. 1995, pp. 363–373.
14. Yarmakovskiy V.N., Bremner T.W. Lightweight aggregate concrete. Present and Future. Proceedings of the III Russian (II International) Conference «Concrete and Reinforced Concrete – A Look into the Future» (organizers: RILEM, Russian Academy of Sciences, FIB). Vol. 1. Plenary reports, pp. 455–465. (In Russian).

A study was made of a heat-insulating material based on foamed liquid glass obtained by processing using microwave technology, which implies swelling due to the transition of water from a liquid state to a vapor state under the influence of electromagnetic waves. Compositions with various liquid glass hardeners were studied in order to find a replacement for the common Na₂SiF₆, since, despite its curing ability, it is toxic. The main problem of a group of materials based on foamed liquid glass is studied – low water resistance. The analysis of the selected modifying additives was carried out in order to compare and identify the optimal option. The initial assessment of the water resistance of the obtained material was determined by the wetting angle method. As a result of the experiments, it was found that Portland cement is the optimal modifying additive for creating an environmentally friendly, fire-resistant, heat-insulating material; based on the identified characteristics, the scope of its possible application is indicated.

I.V. BESSONOV¹, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
M.G. BRUYAKO², Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
E.A. GORBUNOVA^1,2, Engineer, Student (This email address is being protected from spambots. You need JavaScript enabled to view it.);
I.S. GOVRYAKOV^1,2, Engineer, Student (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Research Institute of Building Physics, RAACS (21, Lokomotivny proezd, Moscow, 127238, Russian Federation)
² National Research Moscow State University of Civil Engineering (26, Yaroslavskoye Shosse, Moscow, 129337, Russian Federation)

1. Min’ko N.I., Puchka O.V., Stepanova M.N., Vayse-ra S.S. Teploizolyatsionnyye steklomaterialy. Peno-steklo [Heat-insulating glass materials. Foam glass]. Belgorod: BSTU. 2016. 263 p.
2. Miriuk O.A. Cellular materials based on liquid glass. Universum: Texnicheskie nauki: electronic scientific magazine. 2015. Vol. 4–5 (17). URL: http://7universum.com/ru/tech/archive/item/2162 (In Russian).
3. Dushkina M.A. Development of compositions and technology for the production of foam-glass crystal materials based on silica raw material. Cand. Diss. (Engineering). Tomsk. 2015. 196 p. (In Russian).
4. Habibulin S.A. Development of compositions and technology for the production of modified fluid-based binder and composite materials based on it. Cand. Diss. (Engineering). Tomsk. 2015. 136 p. (In Russian).
5. Zin Min Htet. Composite materials based on liquid-based binder for thermal insulation. Cand. Diss. (Engineering). Moscow. 2020. 136 p. (In Russian).
6. Malyavsky N.I., Zhuravleva O.I. On the possibility of replacing fluorosilicate curing agents of liquid glass with calcium-silicate in the technology of alkaline silicate insulation. Vestnik Evraziiskoi nauki. 2018. No. 5. https://esj.today/PDF/04SAVN518.pdf. (In Russian).
7. Malyavsky N.I., Zvereva V.V. Calcium-silicate hardeners of liquid glass for the production of water-resistant alkaline silicate insulation. Internet-vestnik VolgSACU. 2015. Vol. 2(38). (In Russian).
8. Lotov V.A., Habibulin S.A. Use of modified liquid-ecological, astringent in the production of building materials. Stroitel’nye Materialy [Construction Mayterials]. 2015. No. 1, pp. 72–75. (In Russian).
9. Usova N.T., Lotov V.A., Lukashevich O.D. Water-resistant, non-autoclactive silicate building materials based on sand, liquid compositions and sludge water treatment. Vestnik of the Tomsk State University of Architecture and Civil Engineering. 2013. No. 2, pp. 276–284. (In Russian).
10. Borilo L.P., Lyutova E.S. Influence of titanium oxide additive on the bioproperties of silicate materials. Vestnik TSU. Khimiya. 2015. No. 2, pp. 101–110. (In Russian).
11. Lukashevich O.D., Lotov V.A., Usova N.T., Lukashevich V.N. Production of water-resistant, durable silicate materials based on natural and technogenic material. Vestnik of the Tomsk State University of Architecture and Civil Engineering. 2017. No. 6, pp. 151–160. (In Russian).
12. Zin Min Htet, Tikhomirov I.N. Thermal insulation materials based on foamed liquid glass. Uspekhi v khimii i khimicheskoi tekhnologii. 2017. No. 3, pp. 34–36. (In Russian).
13. Zabolotskaya A.V. Technology and physical-chemical properties of porous composite materials based on liquid glass and natural silicates. Cand. Diss. (Engineering) Tomsk. 2003. 203 p. (In Russian).
14. Filippov V.A., Filippov B.V. Advanced technologies for processing materials with ultra-high-frequency electromagnetic oscillations. Vestnik of the Chuvash State Pedagogical University named after I.Ya. Yakovlev. 2012. No. 4 (76), pp. 181–184. (In Russian).
15. Kalganova S.G., Lavrent’ev V.A., Arkhangel’skii Yu.S., Vasinkina E.Yu., Beloglazov A.P. Microwave energy in the production of composite materials. Reshetnevskiye chteniya. 2017. No. 21–1, pp. 369–371. (In Russian).

The article is devoted to the description of comprehensive studies of the operational humidity of thermal insulation boards with a rigid polyisocyanurate (PIR) foam core used in modern roofing systems. Full-scale surveys of 12 flat roofs insulated with PIR-boards realized at least three years ago and located in all three humidity zones of Russia (9 regions) were carried out. After sampling, the values of the operational humidity of the PIR-boards were determined for all the studied objects. It has been determined that the calculated humidity for the polyisocyanurate boards (PIR) faced on both sides with aluminum foil in modern roofing solutions is 2 % (for the operating conditions of structures A) and 3% (for the operating conditions of structures B). The results are proposed to be used in the preparation of Amendments No. 3 to SP 50.13330.2012 “SNIP 23-02-2003 Thermal protection of buildings” in terms of the calculated thermal performance of the polyisocyanurate foam boards with aluminum facing.

P.P. PASTUSHKOV^1,2, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
D.A. IL’IN^3,4, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
V.N. SHALIMOV⁴, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
I.S. KURILYUK¹, Engineer (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Research Institute of Building Physics Russian Academy Architecture and Construction sciences (21, Lokomotivniy Driveway, Moscow, 127238, Russian Federation)
² Institute of Mechanics Lomonosov Moscow State University (1, Michurinsky Avenue, Moscow, 119192, Russian Federation)
³ Moscow State University of Civil Engineering (National Research University (26, Yaroslavskoye Shosse, Moscow, 129337, Russian Federation)
⁴ LLC “TechnoNICOL-Construction Systems” (room 13/ I, floor 5, 47/5 Gilyarovskogo Street, Moscow, 129110, Russian Federation)

1. Гагарин В.Г., Пастушков П.П. Определение расчетной влажности строительных материалов // Промышленное и гражданское строительство. 2015. № 8. С. 28–33.
1. Gagarin V.G., Pastushkov P.P. Determination of the calculated moisture content of building materials. Promyshlennoe i grazhdanskoe stroitel’stvo. 2015. No. 8, pp. 28–33. (In Russian).
2. Пастушков П.П., Павленко Н.В., Коркина Е.В. Использование расчетного определения эксплуатационной влажности теплоизоляционных материалов // Строительство и реконструкция. 2015. № 4 (60). С. 168–172.
2. Pastushkov P.P., Pavlenko N.V., Korkina E.V. Using the definition of estimated operational moisture of thermal insulation materials. Stroitel’stvo i rekonstrukciya. 2015. No. 4 (60), pp. 168–172. (In Russian).
3. СП 50.13330.2012 «СНиП 23-02-2003 Тепловая защита зданий» (с изменениями № 1, №2).
3. SP 50.13330.2012 «SNiP 23-02-2003 Thermal protection of buildings» (with amendments No. 1, No. 2). (In Russian).
4. Пастушков П.П. О проблемах определения теплопроводности строительных материалов // Строительные материалы. 2019. № 4. С. 57–63. DOI: https://doi.org/10.31659/0585-430X-2019-769-4-57-63
4. Pastushkov P.P. On the problems of determining the thermal conductivity of building materials. Stroitel’nye Materialy [Construction Materials]. 2019. No. 4, pp. 57–63. DOI: https://doi.org/10.31659/0585-430X-2019-769-4-57-63 (In Russian).
5. Grünbauer H.J.M., Bicerano J., Clavel P., Daussin  R.D., de Vos H.A., Elwell M.J., et al. Rigid Polyurethane Foams. In book: Polymeric Foams. 2004. DOI:10.1201/9780203506141.ch7
6. Ashida K. Polyurethane and Related Foams: Chemistry and Technology (1st ed.). CRC Press. 2006. 174 p.
7. Wiedermann R.E., Adam N., Kaufung R. Flame-Retarded, Rigid PUR Foams with a Low Thermal Conductivity. Journal of Thermal Insulation. 1988. Vol 11(4), pp. 242–253.
8. Albrecht W. Cell-gas composition – An important factor in the evaluation of long-term thermal conductivity in closed-cell foamed plastics. Cellular Polymers. 2000. Vol. 19(5), pp. 319–331.
9. Albrecht W., Zehendner H. Thermal conductivity of Polyurethane (PUR) rigid foam boards after storage at 23^oC and 70^oC. Cellular Polymers. 1997. Vol. 16, pp. 35–42.
10. Albrecht W. Change over time in the thermal conductivity of ten-year-old pur rigid foam boards with diffusion-open facings. Cellular Polymers. 2004. Vol. 23(3), pp. 161–172. https://doi.org/10.1177/026248930402300303
11. Гагарин В.Г., Пастушков П.П. Изменение во времени теплопроводности газонаполненных полимерных теплоизоляционных материалов // Строительные материалы. 2017. № 6. С. 28–31.
11. Gagarin V.G., Pastushkov P.P. Change in time of thermal conductivity of gas-filled polymer thermal insulation materials. Stroitel’nye Materialy [Construction Materials]. 2017. No. 6, pp. 28–31. (In Russian).
12. Пастушков П.П., Гагарин В.Г., Ильин Д.А., Нагаев И.Ф. Новые результаты по исследованиям изменения теплопроводности с течением времени плит из пенополиизоцианурата (PIR) современного производства // Строительные материалы. 2022. № 6. С. 30–34. DOI: https://doi.org/10.31659/0585-430X-2022-803-6-30-34
12. Pastushkov P.P., Gagarin V.G., Il’in D.A., Nagaev I.F. New results on research on changes in thermal conductivity over time of boards made of polyisocyanurate foam (PIR) of modern production. Stroitel’nye Materialy [Construction Materials]. 2022. No. 6, pp. 30–34. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2022-803-6-30-34
13. Гагарин В.Г., Пастушков П.П., Реутова Н.А. К вопросу о назначении расчетной влажности строительных материалов по изотерме сорбции // Строительство и реконструкция. 2015. № 4 (60). С. 152–155.
13. Gagarin V.G., Pastushkov P.P., Reutova N.A. On the question of the appointment of the calculated moisture of building materials for sorption isotherm. Stroitel’stvo i rekonstrukciya. 2015. No. 4 (60), pp. 152–155. (In Russian).
14. Методическое пособие по назначению расчетных теплотехнических показателей строительных материалов и изделий. М.: ФАУ «ФЦС», 2019.
14. Methodical manual on the purpose of calculated thermal engineering indicators of building materials and products. Moscow: FAU «FCS», 2019. (In Russian).

The behavior of vibration damping materials used to reduce vibration in structures by absorbing vibration energy (damping) is considered. A comparison was made of the properties of two materials with a cellular structure: Sylomer SR 110 (Austria) and similar, according to the manufacturer, according to the characteristics of Gener VX 110 (Russia). As part of the study, a set of tests was performed to determine the mechanical properties of these materials, as well as their change during aging. It was found that the material Gener VX 110 has a higher creep than Sylomer SR 110, as well as lower aging resistance, which leads to a significant increase in rigidity and a decrease in the effectiveness of vibration isolation. The spread of measured characteristics for Gener VX 110 is higher than for Sylomer SR 110, which requires the introduction of additional safety factors.

L.K. BOGOMOLOVA¹, Candidate of Sciences (Chemistry) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
M.Yu. SMOLYAKOV¹, engineer; V.A. SMIRNOV^1,2, Candidate of Sciences (Engineering)

¹ Scientific-Research Institute of Building Physics of RAACS (21, Lokomotivniy Driveway, Moscow, 127238, Russian Federation)
² National Research Moscow State University of Civil Engineering (26, Yaroslavskoye Highway, Moscow, 129337, Russian Federation)

1. Uzakova L.P., Fayziev S.Kh. The use of vibration damping materials to reduce vibration and noise in the clothing industry. Molodoy ucheniy. 2015. No. 9 (89), pp. 325–327. (In Russian).
2. Budovsky A.V., Bulygin Yu.I., Pavlikov A.V., Tryukhan A.V. Reducing the vibroacoustic activity of floating facilities when using vibration damping materials. Bezopasnost’ tekhnogennykh i prirodnykh sistem. 2023. No. 1, pp. 28–38. (In Russian). DOI: 10.23947/2541-9129-2023-1-28-38
3. Shcherbakov V.I., Kruglov K.M., Aksenov D.V., Shkurko L.S. Experimental assessment of vibration damping characteristics of plates made of different materials. Vestnik mashinostroeniya. 2012. No. 8, pp. 31–34. (In Russian).
4. Wong D.T.H., Williams H.L. Dynamic mechanical and vibration damping properties of polyurethane compositions. Journal of Applied Polymer Science. 1983. Vol. 28. Iss. 7, pp. 2187–2207. https://doi.org/10.1002/app.1983.070280706
5. Ferry J.D. Viscoelastic properties of polymers. 3rd Ed. New York: John Wiley&Sons. 1980.
6. Corsaro R.D., Sperling L.H. Sound and vibration damping with polymers. American Chemical Society. 1990. Vol. 424. DOI: 10.1021/bk-1990-0424
7. Smirnov V.A. Protection of bearing structures of buildings against the influence of vibration generated by railway transport. Zhilishchnoe Stroitel’stvo [Housing Construction]. 2020. No. 12, pp. 40–46. (In Russian). DOI: https://doi.org/10.31659/0044-4472-2020-12-40-46
8. Smirnov V.A., Savulidi M.Yu., Smolyakov M.Yu. Assessment of the impact of vibration on buildings and structures in the zone of influence of the railway. Zhilishchnoe Stroitel’stvo [Housing Construction]. 2022. No. 11, pp. 36–40. (In Russian). DOI: https://doi.org/10.31659/0044-4472-2022-11-36-40
9. Tsukernikov I.E., Tikhomirov L.A., Solomatin E.O. Solving the problems of building acoustics as a factor that ensures the safety and comfort of living in buildings. Zhilishchnoe Stroitel’stvo [Housing Construction]. 2014. No. 6, pp. 49–52. (In Russian).
10. Gagarin V.G., Shubin I.L. The development of theoretical and experimental foundations of building physics as the main factor in ensuring the comfort of living, creativity and healthy human life within the new generation. Fundamental research of the RAACS on scientific support for the development of architecture, urban planning and the construction industry of the Russian Federation in 2011. Scientific works of the RAASN. Vol. 2. Moscow: National Research Moscow State University of Civil Engineering. 2012, pp. 234–238. (In Russian).
11. Khanifov F.M., Zagidullina G.M. The main directions of implementation of the life cycle management system for capital construction projects. Innovations and quality of vocational education: Proceedings of the XV International Scientific and Practical Conference. Kazan. 2021, pp. 3–8. (In Russian).
12. Borisov L.A., Gradov V.A., Tretyakov V.I. et al. Investigation of physical-mechanical and acoustic characteristics of heat and sound insulation materials using the method of artificial aging. Stroitel’stvo i rekonstruktsiya. 2015. No. 4 (60), pp. 4–9. (In Russian).
13. Klimenko V.V., Gorin V.A. Investigation of the dynamic characteristics of materials of elastic substrates of parquet floors during operation. Academia. Arkhitektura i stroitel’stvo. 2010. No. 3, pp. 204–207. (In Russian).
14. Borisov L.A. Gradov V.A., Nasonova E.V. Dynamic characteristics of polyethylene foams under the influence of a long-term load. Problems of environmental safety and energy saving in construction and housing and communal services: Proceedings of the international scientific-practical conference. Kavala (Greece), 2014. pp. 226–233.
15. Tretyakov V.I., Bogomolova L.K., Guzova E.S. Physico-mechanical criteria for evaluating the durability of sealing gaskets for window and door blocks and structural glazing of facades. Stroitel’stvo i rekonstruktsiya. 2016. No. 3 (65), pp. 165–168. (In Russian).
16. Tretyakov V.I., Bogomolova L.K. Determination of the durability of PVC window and door profiles for translucent structures in the Testing Center “Stroypolymertest”. Svetoprozrachnyye konstruktsii. 2003. No. 2, pp. 59–62. (In Russian).
17. Skripchenko D.S., Ovsyannikov S.N. Test method for determination of dynamic modulus of elasticity, dynamic shear modulus and loss coefficient of soundproofing materials. Stroitel’nye Materialy [Construction Materials]. 2017. No. 6, pp. 55–58. (In Russian).
18. Makhmudov U.A., Lelyuga O.V. Experimental studies of elastic-dissipative properties of structural materials and calculation of sound insulation of enclosing structures based on refined characteristics by the SEA method. Selected reports of the 66th University Scientific and Technical Conference of Students and Young Scientists. Tomsk. September 21–25, 2020, pp. 336–343. (In Russian).
19. Ovsyannikov S.N., Lelyuga O.V., Samokhvalov A.S. and others. Experimental studies of elastic-dissipative properties of structural and sealing materials of translucent structures. Stroitel’stvo i rekonstruktsiya. 2022. No. 6 (104), pp. 56–68. DOI: 10.33979/2073-7416-2022-104-6-56-68.
20. Ovsyannikov S.N., Lelyuga O.V., Makhmudov U.A., Shchurova N.E. Study of the elastic-dissipative properties of structural materials of building envelopes. BST: Byulleten’ stroitel’noy tekhniki. 2020. No. 6 (1030), pp. 28–31. (In Russian).
21. Zaborov V.I., Rosin G.S. Measurement of dynamic parameters of soundproofing materials. Akusticheskiy zhurnal. 1961. Vol. 7. No. 1, pp. 92–94. (In Russian).
22. Reference book on protection against noise and vibration of residential and public buildings. Ed. Zaborov V.I. Kiev: Budivelnik. 1989. 160 p.

Gypsum by-products are a good alternative to natural gypsum stone. However, the production of high-quality binders and materials based on them is possible only with the use of non-traditional methods and approaches that avoid the negative impact of the characteristics of gypsum-containing waste on the properties of the final product. One of these technological methods is the manufacture of products using the principles of the semi-dry pressing method. However, due to the high content of the binder component in the pressed raw mix, significant defects in the form of delaminations and wedges can occur on the surface of the products, which negatively affects not only the aesthetic but also the physical and mechanical characteristics of the products. The appearance of such defects is associated with the high adhesion of the binder to the metal surface of the mold, as well as with the near-wall friction of the particles during pressing and extrusion. In this connection, the purpose of this study was to consider the possibility of improving the quality characteristics (appearance, average density, compressive strength) of products manufactured by pressing a semi-dry raw mix. The object of research was a gypsum-containing waste from the biochemical synthesis of citric acid – citrogypsum and a binder based on it. It has been established that other things being equal, the manufacturing parameters, the introduction of a foaming agent additive in the raw mix, and the replacement of the forming surface material with plastic help to eliminate defects on the surface of the samples, as well as to ensure an increase in average density by 10%, and compressive strength by 60.6%.

N.I. ALFIMOVA¹, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
S.Yu. PIRIEVA¹, Assistant (This email address is being protected from spambots. You need JavaScript enabled to view it.);
K.M. LEVICKAYA^1,2, Postgraduate (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Belgorod State Technological University named after V.G. Shukhov (46, Kostukov Street, Belgorod, 308012, Russian Federation)
² Belgorod National Research University (85, Pobedy Street, 308015, Belgorod, Russia Russian Federation)

1. Гипсовые материалы и изделия (производство и применение): Справочник / Под общ. ред. А.В. Ферронской. М.: АСВ, 2004. 488 с.
1. Gipsovye materialy i izdeliya (proizvodstvo i primenenie) Spravochnik. Pod obshhey redakciey A.V. Ferronskoy [Gypsum materials and products (production and use)]. Moscow: ASV, 2004. 488 p. (In Russian).
2. Kamarou M., Korob N., Kwapinski W., Romanovski V. High-quality gypsum binders based on synthetic calcium sulfate dihydrate produced from industrial waste. Journal of Industrial and Engineering Chemistry. 2021. Vol. 100, pp. 324–332. DOI: 10.1016/j.jiec.2021.05.006
3. Lushnikova N., Dvorkin L. 25 – Sustainability of gypsum products as a construction material. Sustainability of Construction Materials (Second Edition). 2016, pp. 643–681. DOI: 10.1016/B978-0-08-100370-1.00025-1
4. Wan Y., Hui X., He X., Li J., Xue J., Feng D., Liu X., Wang S. Performance of green binder developed from flue gas desulfurization gypsum incorporating Portland cement and large-volume fly ash. Construction and Building Materials. 2022. Vol. 348. 128679. DOI: 10.1016/j.conbuildmat.2022.128679
5. Calderón-Morales B.R.S., García-Martínez A., Pineda P., García-Tenório R. Valorization of phosphogypsum in cement-based materials: Limits and potential in eco-efficient construction. Journal of Building Engineering. 2021. Vol. 44. 102506. DOI: 10.1016/j.jobe.2021.102506
6. Pirieva S.Yu., Alfimova N.I., Levickaya K.M. Citrogypsum as a raw material for gypsum binder production. Construction of Unique Buildings and Structures. 2022. No. 2 (100). 10007. DOI: 10.4123/CUBS.100.7
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The industry of low-rise construction, which is dynamically developing at the present time, requires the selection of innovative materials and solutions, including fast-hardening types of binders. It is relevant to obtain composite gypsum binders (CGB) and concretes (solutions) based on them by using the appropriate ratio of components – gypsum binders, Portland cement and a complex of finely dispersed mineral additives that reduce the concentration of Ca(OH)₂ in the liquid phase of the hardening system with the formation of low-base calcium hydrosilicates and other poorly soluble compounds that seal the structure and prevent penetration of moisture into the hardened binder. Materials based on CGB harden quickly enough and gain the required strength. The results of experimental studies presented in the article confirm the activity of fine mineral additives used (quartz sand, metakaolin VMK-45) and are consistent with the indicators of the physical and mechanical characteristics of gypsum cement binder based on them. During the hardening of CGB, the amorphous phase of SiO₂ in the composition of the mineral additives used contributes to the binding of Ca(OH)₂, released during hydration of C₃S. The basicity of the hardening system decreases with the formation of low-base calcium hydrosilicates of the second generation and other neoplasms, which, together with the filler (limestone dust), compact the microstructure of the hardening matrix and, as a result, increase the stability of the composition.

S.A. OTHMAN AZMI, Postgraduate (This email address is being protected from spambots. You need JavaScript enabled to view it.),
N.V. CHERNYSHEVA, Doctor of Sciences (Engineering), Docent, Professor (This email address is being protected from spambots. You need JavaScript enabled to view it.),
M.Yu. DREBEZGOVA, Candidate of Sciences (Engineering), Docent (This email address is being protected from spambots. You need JavaScript enabled to view it.),
E.V. KOVALENKO, Postgraduate (This email address is being protected from spambots. You need JavaScript enabled to view it.),
S.V. MASALITINA, Magistrant, (This email address is being protected from spambots. You need JavaScript enabled to view it.)

Belgorod State Technological University named after V.G. Shukhov (46, Kostyukova Street, Belgorod, 308012, Russian Federation)

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The history of architecture and construction has shown that the traditional architecture of each country has become possible only thanks to the abundance of local materials available to everyone. Given this reality, folk architecture is a materialization of local materials available in every corner manifesting in visible form thanks to the ingenuity of the masters. This natural opportunity has been embodied in the construction of housing in African societies, and Chad is also no exception. The habitat built by artisans was built from available local materials, such as stubble, tree leaves, earth-straw mixture, blocks of earth from unbaked clay (adobe) and others. Over time, housing is being built from blocks of compressed clay, baked bricks, light concrete blocks (cinder blocks) and others. Given the current trend, these materials no longer meet modern challenges, so thinking about developing materials that take into account evolution means finding innovative materials developed on the basis of local resources, taking into account existing realities without compromising the well-being of the future society. The work in this research paper will allow us to briefly lay out the existing materials used in construction in Chad, as well as identify their advantages and disadvantages and offer innovative and sustainable new material for the mass construction of low-rise buildings based on local resources.

S.V. FEDOSOV, Doctor of Sciences (Engineering), Professor, Academician of RAASN (This email address is being protected from spambots. You need JavaScript enabled to view it.),
E. KENEWEI, Graduate Student (This email address is being protected from spambots. You need JavaScript enabled to view it.),
A.A. LAPIDUS, Doctor of Sciences (Engineering), Professor (This email address is being protected from spambots. You need JavaScript enabled to view it.)

National Research Moscow State University of Civil Engineering (129337, Moscow, Yaroslavskoe Highway, 26)

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26. Catalogue bâtiment. Pac la signature du béton naturel. 2020, pp. 11–17. https://www.ets-pac.fr/upload/catalogues/lapac_catalogue_batiment.pdf
27. Mango-Itulamya L.A. Valorisation des gisements argileux pour la fabrication des blocs de terre comprimée. Thèse de doctorat. Université de Liège. 2019, pp. 29–32.
28. Местников А.Е., Семенов С.С., Васильева Д.В. Рациональное использование минерально-сырьевых ресурсов Якутии в технологии строительных материалов // Фундаментальные исследования. 2017. № 12-1. С. 80–84.
28. Mestnikov A.E., Semenov S.S., Vasil’eva D.V. Rational use of mineral resources of Yakutia in the technology of building materials. Fundamental’nyye issledovaniya. 2017. No. 12-1, pp. 80–84. (In Russian).
29. ГОСТ 19222–2019. Арболит и изделия из него. Технические условия. М.: Стандартинформ, 2019. С. 6–8.
29. GOST RF 19222–2019. Arbolit i izdeliya iz nego. Tekhnicheskiye usloviya [Arbolit and products from it. Specifications]. Moscow: Standartinform. 2019, pp. 6–8. (In Russian).

During the survey and work on the reconstruction and restoration of buildings and structures, questions often arise regarding the assessment of the connectivity of elements of stone structures. For example, at the moment there are no reasonable methods for assessing the quality of work to strengthen stone structures that have obvious damage. In addition, questions often arise about the connection between the embedded openings and the main mass of the stone wall. To solve these problems, it is proposed to use an estimate of the coherence function, which is based on the vibration records of the stone structures under study. The seismic background is considered as a dynamic load. The proposed methods can be considered as methods of non-destructive testing, since they require minimal physical impact on the structures under study. The article provides a brief description of the coherence function, the construction of its estimate, as well as the measuring equipment used. As examples of the application of this assessment, the results of processing measurements of two cracks before and after reinforcement work, as well as two embedded openings, are given. Since the methods described in the article are at the stage of development and research, unresolved issues are presented at the moment. In addition, the limitations that arise during measurements and the limits of applicability of the proposed method are listed.

P.A. BAKUSOV^1,2, Engineer, Assistant of the Department of Information Technologies (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Saint Petersburg State University of Architecture and Civil Engineering (4, 2nd Krasnoarmeiskaya Street, Saint Petersburg, 190005, Russian Federation)
² «Georeconstruction» ISP OOO (office 414, 4, Izmaylovskiy Avenue, Saint Petersburg, 190005, Russian Federation)

1. Bendat J., Piersol A. Izmerenie i analiz sluchajnyh processov [Measurement and analysis of random processes]. Moscow: Mir. 1974. 463 p.
2. Bendat J., Piersol A. Primeneniya korrelyatsionnogo i spektral’no analiza [Engineering applications of correlation and spectral analysis]. Moscow: Mir, 1983. 310 p.
3. Jenkins G., Watts D. Spektral’nyj analiz i ego prilozheniya [Digital spectral analysis and its applications]. Vol. 2. Moscow: Mir. 1972. 287 p.
4. Marple Jr.S.L. Tsifrovoi spektral’nyi analiz i ego prilozheniya [Digital spectral analysis]. Moscow: Mir. 1990. 584 p.
5. Otnes R., Enochson L. Prikladnoi analiz vremennykh ryadov [Applied time series analysis]. Moscow: Mir. 1982. 428 p.
6. Randall R.B. Chastotnyj analiz [Frequency analysis]. Kopengagen: Bryul’ i K”er, 1989. 389 p.
7. Ovcharuk V.N. Spectral analysis of signals acoustic emission. Uchenye zametki TOGU. 2013. Vol. 4, No. 4, pp. 974–986. (In Russian).
8. Bartlett M.S. Smoothing periodograms from time-series with continuous spectra. Nature. 1948. Vol. 161, pp. 686–687. DOI: https://doi.org/10.1038/161686a0
9. Bartlett M.S. Periodogram analysis and continuous spectra. Biometrika. 1950. Vol. 37. No. 1/2, pp. 1–16. DOI: https://doi.org/10.2307/2332141
10. Bartlett M.S. Vvedenie v teoriyu sluchainykh protsessov [An Introduction to stochastic processes with special reference to methods and applications]. Moscow: IL. 1958. 384 p.
11. Derkach V.N., Bakusov P.A., Orlovich R.B. Evaluation of the effectiveness of injection and repair of damaged masonry. Stroitel’nye Materialy [Construction Materials]. 2022. No. 9, pp. 55–61. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2022-806-9-55-61
12. Patitz G. Bestandserfassung mit Bauradar – ein zerstörungsfreies Verfahren für die Praxis. Mauerwerk. 2013. Vol. 17. Iss. 4, pp. 196–200. DOI: https://doi.org/10.1002/ dama.201300579
13. Wiggenhauser H., Behrens M., Mouser D., Moryson R.M., Pudovikov S., Herrmann H-G. Non-destructive assessment of retaining wall of former coal mine plant. Mauerwerk. 2018. Vol. 22. Iss. 3, pp. 175–186. DOI: https://doi.org/10.1002/dama.201700021
14. Kwiecien A., Chelmecki J., Matysek P. Non-destructive test of brick columns using change in frequency and inertancy response. Structural Analysis of Historical Constructions. 2012, pp. 2437–2444.
15. Zavalishin S.I., Shablinskii G.E., Zubkov D.A., Rumyantsev A.A. Dinamiceskii monitoring zdanii i sooruzhenii dlya kontrolya ikh seismostoikosti [Dynamic monitoring of buildings and structures to control their seismic stability]. Predotvrashchenie avarii zdanii i sooruzhenii. 2009. No. 2 (2), pp. 1–12. (In Russian).
16. Gentile C., Saisi A., Cabboi A. Dynamic monitoring of a Masonry tower. Structural Analysis of Historical Constructions. 2012, pp. 2390–2397.
17. Elyamani A., Caselles J.O., Clapes J., Roca P. Assessment of dynamic behavior of Mallorca cathedral. Structural Analysis of Historical Constructions. 2012, pp. 2376–2384.
18. Grosel J., Sawicki W., Wojcicki Z. Vibration measurements in analysis of historical structures. Structural Analysis of Historical Constructions. 2012, pp. 2398–2411.

An analysis of the stress-strain state of one of the oldest types of floor structures, namely, masonry vaults supported by steel beams (in some cases, by steel rails), the so-called Monnier vaults, was carried out. As a rule, the indicated constructive solution of ceilings was used in ceilings above basements and has been preserved to this day in Moscow, St.Petersburg and other cities. The analysis was performed for one of the buildings located on Tverskaya Street in Moscow. Taking into account the specifics of the stress-strain state of the structures under consideration, taking into account the presence of damage in some cases, the analysis was carried out in the Lira CAD 2019 (R2) program, in which the material parameters were set according to the 14 piecewise linear law. Based on the results of the calculation, the values of deflections, the maximum values of the forces N_x, N_y, Q_x, Q_y, M_x, M_y, the principal stresses in the lower and upper layers of the roof σ₁ and σ₂, the forces Q_z and M_y in the steel beams of the roof, taking into account their joint work with the vault, were obtained. Design models for laying vaults in linear and non-linear formulations have been built and analyzed. At the same time, the results of a comparison of various models showed that in metal beams with a passive load from the vault without its inclusion in the work, large stresses arise, and they may lose their bearing capacity. The bearing capacity of steel beams was evaluated for two groups of limit states, taking into account their joint work with vaults, as well as the bearing capacity was checked for local stability, taking into account the operation of the vault.

A.I. BEDOV¹, Candidate of Science (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
A.I. GABITOV², Doctor of Science (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
E.V. DOMAROVA¹, Senior lecturer (This email address is being protected from spambots. You need JavaScript enabled to view it.);
A.S. SALOV², Candidate of Science (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ National Research Moscow State University of Civil Engineering (26, Yaroslavskoe Highway, 129337, Moscow, Russian Federation)
² Ufa State Petroleum Technological University (195, Mendeleev, Ufa, 19500, Russian Federation)

1. Krentowski J., Mlonek S., Ziminski K., Tofiluk A. Structural and technological aspects of the historical floors replacement. IOP Conference Series: Materials Science and Engineering. 2019. No. 471 (8), pp. 1–8. DOI: 10.1088/1757-899X/471/8/082057
2. Loleyt A.F. The Monier system: Its application, industrial significance and issues related to the distribution of reinforced concrete. Report. St. Petersburg: Creativity of art printing. 1903. 10 p.
3. Zimin S.S., Bespalov V.V., Kazimirova A.S. Calculation model of a stone arched structure. Bulletin of the Donbass National Academy of Architecture Construction. 2015. No. 3 (113), pp. 33–37.
4. Bedov A.I., Znamensky V.V., Gabitov A.I. Ocenka tekhnicheskogo sostoyaniya, vosstanovlenie i usilenie osnovanij i stroitel’nyh konstrukcij ekspluatiruemyh zdanij i sooruzhenij. Vosstanovlenie i usilenie osnovanij i stroitel’nyh konstrukcij ekspluatiruemyh zdanij i sooruzhenij [Assessment of the technical condition, reconstruction and strengthening of foundations and building structures of buildings and structures in operation. Restoration and strengthening of foundations and building structures of operated buildings and structures]. Moscow: ASV. 2017. 924 p.
5. Lalin V.V., Dmitriev A.N., Diakov S. F., Nonlinear deformation and stability of geometrically exact elastic arches. Magazine of Civil Engineering. 2019. No. 89 (5), pp. 39–51. DOI: 10.18720/MCE.89.4
6. Fabrichnaya K.A., Sharafutdinova K.I. On the issue of vaults (of the “Monier” type) composite materials during reconstruction. Izvestiya KGASU. 2019. No. 4 (50), pp. 210–219. (In Russian).
7. Bedov A.I., Gabitov A.I., Gallyamov A.A., Salov A.S., Gaisin A.M. Application of computer modeling in assessing the stress-strain state of load-bearing structures of masonry buildings. International Journal for Computational Civil and Structural Engineering. 2017. № 1, pp. 42–49.
8. Strakhov D.E., Gimranov L.R., Sakhapova A.I. Application of volumetric finite elements, on the example of a fire tower located in Sarapul, which is an architectural monument of federal significance. Izvestiya KGASU. 2018. No. 3 (45), pp. 153–161. (In Russian).
9. Pavlov V.V., Horkov E.V. Experimental studies of reinforced brick arches with horizontal movement of supports. Izvestiya KGASU. 2014. No. 2 (28), pp. 90–96. (In Russian).
10. Sokolov B.S., Antakov A.B. Issledovaniya szhatyh elementov kamennyh i armokamennyh konstrukciy [Studies of compressed elements of stone and reinforced stone structures]. Moscow: ASV. 2010. 104 p.
11. Gabitov A.I., Udalova E.A., Salov A.S., Chernova A.R., Pyzhyanova D.V., Yamilova V.V. Historical aspects of production and application of high-void ceramic products. Istoriya nauki i tekhniki. 2017. No. 6, pp. 58–65. (In Russian).
12. Bespalov V.V., Zimin S.S. Strength of masonry vaulted structures. Stroitel’stvo unikal’nykh zdanii i sooruzhenii. 2016. No. 11 (50), pp. 37–51. (In Russian).
13. Isekeev I.D., Trofimov A.V. Improvement of the calculation methodology of flat reinforced concrete arches supported by metal beams. Vestnik grazhdanskikh inzhenerov. 2018. No. 1 (66), pp. 28–33. (In Russian).
14. Francesca Giulia Carozzi, Gabriele Milani, Carlo Poggi. Mechanical properties and numerical modeling of Fabric Reinforced Cementitious Matrix (FRCM) systems for strengthening of masonry structures. Composite structures. 2014. Vol. 107, pp. 711–725.
15. Borri A., Castori G., Сorradi M. Intrados strengthening of brick masonryьarches with composite materials. Composites. 2011. Vol. 42. Part B, pp. 1164–1172.
16. Bedov A.I., Gaisin A.M., Gabitov A.I., Kuznetsov D.V., Salov A.S., Abutalipova E.M. Comparative evaluation of the determination of physical and mechanical characteristics of high-void ceramic wall products based on modern software systems. Vestnik MGSU. 2017. Vol.  12. No. 1 (100), pp. 17–25. (In Russian).
17. Gassiev A.A., Granovsky A.V. Dynamic tests of masonry samples reinforced with canvases made of carbon fiber fabric. Seismostoikoe stroitel’stvo. Bezopasnost’ sooruzhenii. 2015. No. 2, pp. 29–35. (In Russian).
18. Khadzhishalapov G.N., Nazhuev M.P., Salakhov E.A., Isaeva U.I., Abdurahimov M.Sh., Hasanov T.A. Issues of sustainable development in the industry of building materials and structures. Vestnik of the Perm National Research Polytechnic University. Applied Ecology. Urbanistics. 2022. No. 1, pp. 47–58. DOI: 10.15593/2409-5125/2022.1.04
19. Gabitov A.I., Ryazanova V.A., Salov A.S., Gaisin A.M., Timofeev A.A. Manufacture of construction materials by energy-saving technology through the example of the Bashkir region. IOP Conference Series: Materials Science and Engineering. 2020. Vol. 907. Iss. 1. 012049. DOI 10.1088/1757-899X/907/1/012049

The article is devoted to the description of complex studies of the influence of various factors on the thermal conductivity of samples of large-format vertically perforated clay blocks of domestic production of 6 types different samples. Problems are described when testing the thermal conductivity of large-format vertically perforated clay blocks according to the methods of existing local standards. The research were carried out according to GOST 7076 on a modern equipment, which allowed us to find a number of dependencies. The influence of the following factors on the thermal conductivity of a clay block in a dry state was established: number of rows of voids in clay block, shape of voids, density and thermal conductivity of a ceramic cork. The best thermal values were determined for clay blocks with an HV design of voids, with number of rows of voids more than 6.8 pieces per 100 mm of length and the lowest density and thermal conductivity of the ceramic cork. Separately, it was noted that the presence of large holes for gripping with fingers when installing masonry in blocks has a negative effect on its thermal conductivity. The new results obtained are of great practical importance due to the widespread use of vertically perforated clay block in modern construction. Prospects for further research are described to determine the degree of influence of various factors on the thermal conductivity of clay blocks, to identify the optimal shape of voids, as well as to establish the dependence of thermal conductivity on average temperature and operating humidity.

P.P. PASTUSHKOV^{1, 2}, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
N.V. PAVLENKO^{1, 2}, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
S.I. SMIRNOV³, Engineer (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Scientific-Research Institute of Building Physics of RAACS (21, Lokomotivniy Driveway, Moscow, 127238, Russian Federation)
² Institute of mechanics Lomonosov Moscow State University (1, Michurinsky Avenue, Moscow, 119192, Russian Federation)
³ Association of Ceramic Materials Manufacturers (115477, Moscow, Kavkazsky Boulevard, 20 p. 1)

1. Semenov A.A. Trends in development of brick industry and brick housing construction in Russia. Stroitel’nye Materialy [Construction Materials]. 2018. No. 8, pp. 49–51. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2018-762-8-49-51
2. Rubtsov O.I., Bobrova E.Yu., Zhukov A.D., Zinov’eva E.A. Ceramic brick, stones and the full brick walls. Stroitel’nye Materialy [Construction Materials]. 2019. No. 9, pp. 8–13. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2019-774-9-8-13
3. Grinfeld G.I., Vishnevsky A.A., Pastushkov P.P., Kozlov A.N. Brick facades. Correct technical solutions and examples of successful implementation. Stroitel’nye Materialy [Construction Materials]. 2017. No. 4, pp. 47–50. (In Russian).
4. Pastushkov P.P. On the problems of determining the thermal conductivity of building materials. Stroitel’nye Materialy [Construction Materials]. 2019. No. 4, pp. 57–63. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2019-769-4-57-63
5. Pastushkov P.P. New results and methodological developments on thermal conductivity studies of autoclave cellular concrete of modern production. Stroitel’nye Materialy [Construction Materials]. 2022. No. 3, pp. 46–50. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2022-800-3-46-50
6. Morales M.P., Juárez M.C., Muñoz P., Gómez J.A. Study of the geometry of a voided clay brick using non-rectangular perforations to optimise its thermal properties. Energy and Buildings. 2011.Vol. 43. Iss. 9.
7. Juárez M.C., Morales M.P., Muñoz P., Mendívil M.A. Influence of horizontal joint on the thermal properties of single-leaf walls with lightweight clay blocks. Energy and Buildings. 2012. Vol. 49.
8. Kiselev I.Ya. Improving the accuracy of determining the thermophysical properties of insulating building materials with regard to their structure and characteristics of operational impacts. Doctor diss. (Engineering). Moscow. 2006. 366 p. (In Russian).
9. Pastushkov P.P., Gagarin V.G. Studies of the dependence of thermal conductivity and the coefficient of thermal quality on the density of autoclaved aerated concrete. Stroitel’nye materialy [Construction Materials]. 2017. No. 5, pp. 26–28. (In Russian).
10. Gagarin V.G., Pastushkov P.P. Determination of the calculated moisture content of building materials. Promyshlennoe i grazhdanskoe stroitel’stvo. 2015. No. 8, pp. 28–33. (In Russian).

The analysis of the compliance of the hood furnace with the requirements of the best available technologies of ceramic production from the point of view of energy and ecology is given. The high energy efficiency of the hood furnace as a firing unit of various types of ceramic products - full-bodied, face, porous and clinker bricks, as well as ceramic tiles, porcelain stoneware, tiles, foam glass and foam ceramics is shown. It is substantiated that the use of recuperative burners and a jet-flare afterburner makes it possible to reduce the level of emissions of harmful substances to the requirements for classical heating furnaces, completely eliminating emissions of volatile organic substances into the atmosphere.

V.V. KURNOSOV, Candidate of Sciences (Physics and Mathematics) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
V.R. TIHONOVA, Engineer

OOO «KOMAS» (8A, Martovskaya Street, Aprelevka, 143362, Moscow Region, Russian Federation)

1. Kurnosov V.V., Dorozhkin A.A., Kalinina N.N., Tikhonova V.R., Filatov A.V. Energy-efficient technologies for firing ceramic products in chamber kilns. Stroitel’nye Materialy [Construction Materials]. 2016. No. 4, pp. 37–40. (In Russian).
2. Guseva T.V., Zakharov A.I., Molchanova Ya.P., Vartanyan M.A., Akberov A.A. Best available technologies for the production of ceramic building materials as a tool for environmental regulation of the industry. Stroitel’nye Materialy [Construction Materials]. 2016. No. 4, pp. 4–9. (In Russian).
3. Informatsionno-tekhnicheskiy spravochnik «Proiz-vodstvo keramicheskikh izdeliy» ITS 4 [Information and technical reference book “Production of ceramic products” ITR 4]. Moscow: Byuro NDT. 2015. 222 p.
4. Amr Osama, Fatheya Soliman. Industrial Energy Efficiency. Benchmarking-Report of the Ceramics Sector. 2016. https://ieeegypt.org/wp-content/uploads/2017/01/BM-Report-Ceramics.pdf
5. GOST R 55646–2013. Resource saving. Production of bricks and ceramic stone. Guidance on the application of the best available technologies for improving energy efficiency and environmental performance. Moscow: Standartinform. 2014. (In Russian).
6. Preobrazhensky N.I. Kontrol’ za ratsional’nym ispol’zovaniyem gaza [Control over the rational use of gas]. Leningrad: Nedra. 1983. p. 368.
7. Ravich M.B. Uproshchennaya metodika teplotekhnicheskikh raschetov [Simplified method of heat engineering calculations]. Moscow: Nauka. 1964.
8. OECD (2019), Best Available Techniques for Preventing and Controlling Industrial Pollution, Activity 3: Measuring the Effectiveness of BAT Policies, Environment, Health and Safety, Environment Directorate, OECD.
9. Lecomte T., Ferreria De La Fuente J., Neuwahl F., Canova M., Pinasseau A., Jankov I., Brinkmann T., Roudier S. and Delgado Sancho L., Best available techniques (BAT) reference document for large combustion plants. Industrial emissions directive 2010/75/EU (Integrated Pollution Prevention and Control), EUR 28836 EN, Publications Office of the European Union, Luxembourg, 2017, ISBN 978-92-79-74303-0, doi:10.2760/949, JRC107769.
10. Shakhov I.I., Kurnosov V.V. Four-chamber kiln for firing ceramic products. Stroitel’nye Materialy [Construc-tion Materials]. 2003. No. 2. p. 24. (In Russian).
11. Decree of the Government of the Russian Federation of September 28, 2015 No. 1029 “On approval of the criteria for classifying objects that have a negative impact on the environment as objects of categories I, II, III and IV.” (In Russian).

A review of well-known screw presses for the ceramic industry has been carried out. The problem of delamination (strill formation) of molded products is indicated. The design of the unit for plastic molding of a strip bar, developed in 2021 by Inta-Stroy, consisting of a vane extruder and a mixer of the Cascade type as a mixing unit, is considered. The high quality of mixing has been established at the Cascade installations in comparison with single-shaft and double-shaft mixers. The elimination of sticking of raw materials in the vacuum chamber was confirmed due to the design improvement of the loading neck. An increase in the force of axial pressure due to the use of blades with a smaller “angle of attack” compared to the screw was revealed. The formation of streaks in the clay beam was eliminated due to the use of forming discs that prevent twisting of the material. It is noted that a denser raw brick is obtained, as well as the possibility of molding a raw brick from less plastic clays and at a lower moisture content of the raw material.

I.F. SHLEGEL¹, Candidate of Sciences (Engineering), director,
S.G. MAKAROV¹, engineer, head of department,
S.S. SHUL’GA¹, engineer, head of department,
S.N. SAPEL’NIKOV¹, engineer, deputy head of department;
L.A. BAGAEVA², director

¹ Institute of New Technologies and Automation of Building Materials Industry (OOO «INTA-STROY») (100, 1-ya Putevaya Street, 644113, Omsk, Russian Federation)
² Trading House “Inta-Stroy” (100, 1-ya Putevaya Street, 644113, Omsk, Russian Federation)

1. Willi Bender, Hans H. Boger. A Short History of the Extruder in Ceramics // Frank Handle. Extrusion in Ceramics. Leipzig, Germany. 2007. 468 p.
2. Materials of the site of the company Verdes, Spain (date of access: 04/19/2023). https://verdes.ru/machines.html
3. Materials of the site of the company Morando, Italy (date of access: 04/25/2023). https://www.rietermorando.com/product/18
4. Materials of the site of the company STEEL & Sons, USA (date of access: 04/25/2023). https://www.jcsteele.com/machinery/extruders-and-pug-sealers/
5. Materials of the site of the company Händle, Germany (date of access: 04/25/2023). https://www.haendle.com/produkte/formgeben-extrudieren/vakuumaggregate-futura-ii
6. Materials of the site of the company BONGIOANNY, Italy (date of access: 04/19/2023) https://www.bongioannimacchine.it/heavy_clay_technology/it/10-macchine
7. Materials of the site of the company Plinfa, Ukraine (date of access: 04/19/2023). https://www.plinfa.com/ru/category/extruders
8. Materials of the site of the company Petersen Service, Germany (date of access: 04/25/2023). https://www.rehart.de/angebot/maschinen-anlagenbau/ziegelei-produkte-petersenservice/formgebung/
9. Materials of the site of the company Aweld, Czech Republic (date of access: 04/25/2023). https://www.aweld.net/ru/site/products
10. Materials of the site of the company Strommashina, Republic of Belarus (date of access: 04/25/2023). https://www.strommashina.mogilev.by/pequipment/cbrick/12-brick-molding/103-scpress
11. Materials of the site of the company Vicentini, Italy (date of access: 04/25/2023). https://www.setecsrl.it/en/index_vicentini.php
12. Materials of the site of the company CAPACCIOLY, Italy (date of access: 04/25/2023). https://www.capaccioli.com/prodotti/speciale-settore-laterizio/
13. Materials of the site of the company IPIAC NERY, Portugal (date of access: 04/27/2023). https://www.ipiac-nery.com/copia-de-cerámica-estructural
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15. Patent RF 2772394. Shnekovyj press [Screw press]. Shlegel’ I.F. Declared 29.10.2021. Published 19.05.2022. Bulletin No. 14. (In Russian).
16. Shlegel’ I.F., Shaevich G.Ja., Karabut L.A., Pashkova E.B., Spitanov V.V., Astaf’ev V.A. Installation “Cascade” for the brick industry. Stroitel’nye Materialy [Construction Materials]. 2005. No. 2, pp. 20–22. (In Russian).
17. Shlegel’ I.F., Shaevich G.Ja., Astaf’ev V.A., Karabut L.A. Industrial installation “Kaskad-13” for clay preparation. Stroitel’nye Materialy [Construction Materials]. 2005. No. 10, pp. 30. (In Russian).
18. Shlegel’ I.F., Shaevich G.Ja., Gudalov O.V. Prospects for the use of installations of the “Kaskad” series in the technology of production of refractories. Novye ogneupory. 2008. No. 12, pp. 64–66. (In Russian).
19. Shlegel’ I.F., Rukavicyn A.V., Andrianov A.V. Use of “Kaskad” series plants in the technology of semi-dry brick pressing. Stroitel’nye Materialy [Construction Materials]. 2010. No. 4, pp. 58–59. (In Russian).
20. Shlegel’ I.F., Makarov S.G., Vasjakin A.M. Expanding the capabilities of “Kaskad” installations. Stroitel’nye Materialy [Construction Materials]. 2017. No. 11, pp. 47–49. (In Russian).
21. Shlegel’ I.F., Shaevich G.Ja., Karabut L.A., Noskov A.V., Astaf’ev V.A., Molodkina L.N., Kotelin P.L., Korovickij N.L. New features of the “Kaskad” installation. Stroitel’nye Materialy [Construction Materials]. 2007. No. 2, pp. 48–50. (In Russian).
22. Shlegel’ I.F., Shaevich G.Ja., Noskov A.V., Astaf’ev V.A., Andrianov A.V., Molodkina L.N. A new generation of clay processing plants “Kaskad”. Stroitel’nye Materialy [Construction Materials]. 2008. No. 4, pp. 34–35. (In Russian).
23. Patent RF 2771476. Zagruzochnaja gorlovina shnekovyh ustrojstv [Loading neck of screw devices]. Shlegel’ I.F. Declared 27.12.2021. Published 04.05.2022. Bulletin No. 13. (In Russian).