THE EFFECT OF PRELIMINARY ELECTRIC RADIO HEATING ON THE PHYSICAL AND THERMAL CHARACTERISTICS OF THE HEAT-RESISTANT CERAMZITONE-CONCRETE BASED ON COMPOSITIVE BINDER OF LOCAL MINERAL RAW MATERIALS

Objectives. The aim of the study is to increase the physico-thermal and operational characteristics of heat-resistant ceramsite concrete with an activated binder by pre-heating the mixture.

Method. To conduct the study, a technique was developed by the Research Institute of Concrete and Reinforced Concrete named after A.A. Gvozdev.

Results. An analysis of the study results of the effect of preliminary electric heating on the physico-thermal characteristics of heat-resistant ceramsite concrete on the basis of a composite binder showed that, in comparison with drying at a temperature of 105º, the operational properties of heat-resistant ceramsite concrete are enhanced by uniform heating of the samples along the concrete body. This isdue to the pore pressure in the concrete structure being reduced by removing physically bound water. Ceramsite is used as large filler while ceramsite sand is used as small filler; activated composite combination of local mineral raw materials consisting of Portland cement and calcined argillic clay is used as a binder. In the concrete body, due to the removal of physically bound water caused by the decrease in pore pressure, the formation of cracks in the interporal partitions decreases, preventing the explosive destruction of heat-resistant ceramsite concrete and improves its physico-mechanical, thermal and operational characteristics. Activated composite binder based on the combination of Portland cement and fine ground argillite clay reduces shrinkage deformations and increases the concrete strength as well as its heat resistance. Concretes with activated composite binder are less susceptible to volume change during the heating process,contributing to greater preservation of concrete strength and structure due to lower stress levels caused by the temperature deformations.

Conclusion. The composition of the developed heat-resistant ceramsite concrete allows its use for monolithic lining of the walls of a tunnel kiln for burning ceramic bricks, as well as various concreting furnaces for the construction industry. The conducted research demonstrates the possibility and expediency of using electric heating for the hardening of heat-resistant ceramsite concrete with a composite binder. The use of electric heating increases the strength of heat-resistant ceramsite concrete both before and after heating to high temperatures. Optimised modes of electric heating of heat-resistant ceramsite concrete with a composite binder are established.

1. Fedorov A.V., Mikhal'chuk P.A. Razrabotka rezhimov elektroprogreva zharostoikikh betonov. Sb. tr NIIZhB. 1964. S.214-227. [Fedorov A.V., Mikhal'chuk P.A. Development of electric heating modes of heat-resistant concrete. Sb. tr NIIZhB. 1964. P. 214-227. (in Russ.)]

2. Khadzhishalapov G.N. Vliyanie predvaritel'nogo razogreva na termomekhanicheskie svoistva zharostoikogo shamotnogo betona na silikat-natrievom kompozitsionnom vyazhushchem. Dis. kand.tekhn. nauk. M.; 1995. S. 22- 25. [Khadzhishalapov G.N. Effect of preheating on the thermomechanical properties of refractory chamotte con-cretewith a silicate-sodium composite binder. PhD in technical sciences thesis. M.; 1995. P. 22-25. (in Russ.)]

3. Toturbiev B.D., Khadzhishalapov G.N., Manturov Z.A. i dr. Mestnye stroitel'nye materialy, poluchennye po resur-sosberegayushchim ekologicheski chistym i naukoemkim tekhnologiyam. Sb tr. Akademiya nauk. 1994. S. 12-15. [Toturbiev B.D., Khadzhishalapov G.N., Manturov Z.A. et al.Local building materials obtained by resource-saving environmentally friendly and science-intensive technologies. Collection of works of RAS. 1994. P. 12-15. (in Russ.)]

4. Nekrasov K.D. Razvitie tekhnologii zharostoikikh betonov. Sb.tr. NIIZhB. 1981. S. 3-11. [Nekrasov K.D. Devel-opment of technology of heat-resistant concrete. Sb.tr. NIIZhB. 1981. P. 3-11. (inRuss.)]

5. Nekrasov K.D. Zhukov V.V., Gulyaeva V.F. Sushka i pervyi nagrev teplovykh agregatov iz zharostoikikh betonov. M.: Stroiizdat; 1976. 96 s. [Nekrasov K.D. Zhukov V.V., Gulyaeva V.F. Drying and first heating of heat unit from heat-resistant concrete. M.: Stroiizdat; 1976. 96 p. (in Russ.)]

6. Remnev V.V. Zharostoikie betony i vozmozhnosti ikh primeneniya dlya teplovykh agregatov. Stroitel'nye materi-aly. 1996;3:18-19.[Remnev V.V. Heat-resistant concrete and the possibility of their use for thermal units. Construction Materials. 1996;3:18-19. (in Russ.)]

7. Milonov V.M. Zharostoikii beton i zhelezobetonov v teplovykh agregatakh khimicheskoi promyshlennosti. Beton i zhelezobeton. 1972;2:11-15.[Milonov V.M. Heat-resistant concrete and reinforced concrete in thermal units of the chemical industry. Beton i zhelezobeton. 1972;2:11-15. (in Russ.)]

8. Mesenyashin G.V., Zalizovskii E.V. Ispol'zovanie keramzita v zharostoikom betone na VGTs v ograzhdayushchikh konstruktsiyakh teplovykh agregatov. Zharostoikie materialy, izdeliya i konstruktsii. Chelyabinsk; 1987. C. 43-44. [Mesenyashin G.V., Zalizovskii E.V. The use of ceramsite in heat-resistant concrete on the high alumina cement in the enclosing structures of thermal units. Heat-resistant materials, products and constructions. Chelyabinsk; 1987. C. 43-44. (in Russ.)]

9. Fervorner O., Berndt K. Ogneupornye materialy dlya steklovarennykh pechei. M.: Stroiizdat; 1984. 260 s. [Fer-vorner O., Berndt K. Refractory materials for glass melting furnaces. M.: Stroiizdat; 1984. 260 p. (in Russ.)]

10. Rebstadt G. Brennwagenaufbauten und Brennhilfsmittel fur die Grobkeramik. Ziegelind. Int. 1999;52(8):20-30.

11. Busby T. S. Tank Blocks for Glass Furnaces. Society of Glass Technology. 1966. P. 47-51.

12. Arbuzova T.B., Korenkova S.F., Brusenkov G.N. Issledovanie mestnykh materialov. Stroitel'nye materialy. 1988;4:20-21. [Arbuzova T.B., Korenkova S.F., Brusenkov G.N. Study of local materials. Construction Materials. 1988;4:20-21. (in Russ.)]

13. Tekhnologiya izgotovleniya zharostoikikh betonov: (NIIZhB Sprav. Posobie k SniPu). M.: Stroiizdat; 1991. 63 s. [Manufacturing technology of heat-resistant concrete: (NIIZHB Reference Guide for SNiP).). M.: Stroiizdat; 1991. 63 p. (in Russ.)]

14. Khadzhishalapov G.N., Kurbanov R.M. Zharostoikii bazal'tovyi beton na aktivirovannom kompozitsionnom vyazhushchem izmestnogo mineral'nogo syr'ya. Makhachkala: Izdatel'stvo “Format”; 2017. 156 s.[Khadzhishala-pov G.N., Kurbanov R.M. Heat-resistant basalt concrete with the activated composite binder made of local mineral raw materials. Makhachkala: Publishing House “Format”; 2017. 156 p. (in Russ.)]

15. Pryadko V.M., Borodin A.A. Issledovanie tekhnologii formirovaniya i teplovoi obrabotki blokov iz zharostoikogo betona. Tez. dokl. respubl. konf. “Opyt primeneniya zharostoikikh betonov v promyshlennosti i stroitel'stve”. Dne-propetrovsk; 1978. S.18-19.[Pryadko V.M., Borodin A.A. Research of technology of formation and heat treatment of blocks from heat-resistant concrete. Abstracts of Republican conference “Experience of using heat-resistant con-crete in industry and construction”. Dnepropetrovsk; 1978. P.18-19. (in Russ.)]

16. Bisultanov R.G., Murtazaev A.Yu., Salamanova M.Sh. Tsementy nizkoi vodopotrebnosti na osnove aktivnoi mineral'noi dobavki razlichnogo proiskhozhdeniya. Vestnik Dagestanskogo gosudarstvennogo tekhnicheskogo uni-versiteta. Technicheskei nauki. 2016;1:98 – 107. [Bisultanov R.G., Murtazaev A.Yu., Salamanova M.Sh. Low water cements based on active mineral additives of various origins. Herald of Dagestan State Technical University. Tech-nical Sciences. 2016;1:98 – 107. (in Russ.)]

17. Biryukov A.I. Intensifikatsiya izgotovleniya izdelii iz keramzitobetona metodom goryachego formovaniya. Khar'kov: Izdatel'stvo Vysshaya shkola pri KhGU; 1977. 52 s.[Biryukov A.I.Intensification of the production of ceramsite concrete products by the hot forming method. Khar'kov: Izdatel'stvo Vysshaya shkola pri KhGU; 1977. 52 p. (in Russ.)]

18. Krylov B.A., Li A.I. Forsirovannyi elektrorazogrev betona. M.: Stroiizdat; 1975. 160 s. [Krylov B.A., Li A.I. Forced electrical heating of concrete. M.: Stroiizdat; 1975. 160 p. (in Russ.)]

19. Nekrasov K.D., Maslennikova M.G. Legkie zharostoikie betony na poristykh zapolnitelyakh. M: Stroiizdat; 1982. 162 s.[Nekrasov K.D., Maslennikova M.G. Lightweight heat-resistant concretes with porous fillers. M: Stroiizdat; 1982. 162 p. (in Russ.)]

20. Satalkin A.V., Komokhov P.G. Vliyanie rezhimov elektrorazogreva smesi na svoistva betona i keramzitobetona. Beton i zhelezobeton. 1969;11:17-21.[Satalkin A.V., Komokhov P.G. Influence of mixture electric heating on the properties of concrete and ceramsite concrete. Beton i zhelezobeton. 1969;11:17-21. (in Russ.)]