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