Assessment and Characteristics of Molding Masses Based on Loam during Production Soft Molded Ceramic Brick

опThe article discusses the issues of assessing the properties of loams and selecting the composition of molding compounds based on them for the production of ceramic bricks using the soft molding method. It is noted that for soft molding technology, to date, no recommendations have been developed for the evaluation of raw materials with the establishment of relationships between the composition, technological properties, molding features and aesthetic features of the front edges of products. According to technological features, the method of soft molding of ceramic bricks is conventionally divided into 4 methods: manual molding, accelerated molding, pressing method and vibration molding method. The results of our work made it possible to identify the main indicators when assessing clay raw materials and to develop the basic principles for selecting the composition of molding masses. Thus, the critical compression stress and the degree of deformation of the workpieces should be on average 0.2–0.8 kg/cm² and 3–5 units, respectively. In this case, the molding masses should have the minimum possible water content and stickiness, have minimal air shrinkage (less than 6–7%), and be slightly or moderately sensitive to drying. An algorithm has been developed for selecting molding compounds, including determination, in addition to generally accepted indicators, such as the degree of deformation and critical compressive stress at different water contents, specific penetration resistance, determination of the optimal electrolyte content, and stickiness. For typical loams, the dependences of the degree of deformation of the samples and the critical compressive stress on the water content of the molding masses are shown, as well as the influence of electrolytes on the water content. It has been shown that the introduction of electrolytes can significantly reduce the water content of molding masses. It is noted that the genesis of loams, their variable composition and the frequent presence of undesirable harmful impurities predetermined the situation that high-quality loams that meet the necessary requirements are quite rare and the only alternative can be the selection of compositions of molding compounds based on correct scientific and methodological approach.сание

Yu.I. NEBEZHKO, Engineer, Graduate student (This email address is being protected from spambots. You need JavaScript enabled to view it.),
V.D. KOTLYAR, Doctor of Sciences (Engineering), Professor, Head of the Department of Construction Materials (This email address is being protected from spambots. You need JavaScript enabled to view it.)

Don State Technical University (1, Gagarina Square, Rostov-on-Don, 344003, Russian Federation)

1. Meskhi B.Ch., Bozhko Yu.A., Terekhina Yu.V., Lapunova K.A. Brick-design and its main elements. Stroitel’nye Materialy [Construction Materials]. 2020. No. 8, pp. 47–51. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2020-783-8-47-51
2. Bozhko Y.A, Lapunova K.A., Ovdun D.A. Evaluation of the Aesthetic and Decorative Properties of Ceramic Bricks. XV International Scientific Conference «Interagromash 2022». Lecture Notes in Networks and Systems. 2023. Vol. 575. https://doi.org/10.1007/978-3-031-21219-2_344.
3. Gerard C.J. Lynch. Brickwork: History, technology and practice: Vol. 2. Routledge, 2015. 220 р. ISBN 1317741293, 9781317741299
4. Bozhko Y.A, Lapunova K.A. Application of facing brick of soft moulding in modern architecture. Dizain. Materialy. Tekhnologiya. 2018. No. 1, pp. 61–65. (In Russian).
5. Fedosov S.V., Kenewei E. Lapidus A.A. In search of innovative materials for mass construction of low-rise buildings in the Republic of Chad. Stroitel’nye Materialy [Construction Materials]. 2023. No. 5, pp. 72–78. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2023-813-5-72-78
6. Frolov V.T. Litologiya. Kniga 2. [Lithology. Book 2]. Moscow: Moscow State University. 1993. 432 p.
7. Industry standard 21-78–88 «The raw material is clay (rocks) for the production of ceramic bricks and stones. Technical requirements. Test methods». Moscow: All-Union Scientific Research Institute of Building Materials. 1988. 59 p. (In Russian).
8. Kondratenko V.A. Keramicheskie stenovye materialy: optimizatsiya ikh fiziko-tekhnicheskikh svoistv i tekhnologicheskikh parametrov proizvodstva [Ceramic wall materials: optimization of their physical and technical properties and technological production parameters]. Moscow: Composite. 2005. 509 p.
9. Nebezhko Yu.I., Lapunova K.A. Features of the front surface of soft molded ceramic bricks. III All-Russian Scientific Conference «Construction Materials Science: Present and Future». Moscow. 2023. Vol. 1, pp. 210–216. (In Russian).
10. Kotlyar V.D., Yavruyan Kh.S., Bozhko Y.A., Nebezhko N.I. Features of the production of ceramic facing brick soft molding on the basis of opoka-like rocks. Stroitel’nye Materialy [Construction Materials]. 2019. No. 12, pp. 18–22. (In Russian). DOI: https://doi.org/10.31659/0585-430X-2019-777-12-18-22
11. Nebezhko Yu.I. Structural features of ceramic masses based on loams and refractory clays in the production of soft molded bricks. XVIII International Scientific and Technical Conference of Young Scientists, dedicated to the memory of Professor V.I. Kalashnikov «Theory and practice of increasing the efficiency of building materials». Penza. 2023. Vol. 1, pp. 150–157. (In Russian).
12. Guzman P.Ya. Khimicheskaya tekhnologiya keramiki [Chemical technology of ceramics]. Moscow: Stroymaterialy. 2003. 496 p.
13. Händle F. Extrusion in ceramics. Springer Berlin Heidelberg New York. 2007. 470 p.
14. Stolboushkin A.Yu., Fomina O.A, Shevchenko V.V., Berdov G.I., Druzhinin M.S., Kambalina I.V. Study of the operational properties of ceramic bricks with a matrix structure. Stroitel’nye Materialy [Construction Materials]. 2017. No. 9, pp. 9–13. (In Russian).
15. Kotlyar A.V., Stolboushkin A.Yu. Evaluation of clay shales from coal waste heaps in the Rostov region for the production of building ceramics. VI International Scientific and Practical Conference «Quality. Technologies. Innovation». Novosibirsk. 2023. 1 CD-ROM, pp. 4–11. (In Russian).
16. Gur’eva V.A., Doroshin A.V. Application of theoretical calculations in the selection of ceramic masses for the production of ceramic bricks using the example of the Buguruslan deposit. All-Russian scientific and practical conference with international participation «Current problems of integration of science and education in the region». Buzuluk. 2023. Vol. 1, pp. 250–255. (In Russian).
17. Kotlyar V.D., Nebezhko N.I., Bozhko Yu.A. Study of clay-carbonate types of opoka-like rocks as raw materials for producing light-colored clinker bricks. I All-Russian scientific conference dedicated to the 90th anniversary of the outstanding materials scientist, academician of the RAASN Yu.M. Bazhenov «Construction materials science: present and future». Moscow. 2020. Vol. 1, pp. 265–269. (In Russian).
18. Sizova A.V., Shoeva T.E., Storozhenko G.I. Shock wave activation of clay raw materials in the production of ceramic materials. 5th International Scientific and Practical Conference «Resource Conservation and Ecology of Building Materials, Products and Structures». Kursk. 2022. Vol. 1, pp. 264–267. (In Russian).
19. Ezersky V.A. Clinker. Technology and properties. Stroitel’nye Materialy [Construction Materials]. 2011. No. 4, pp. 79–81. (In Russian).