THE INFLUENCE OF THE FILLER GRAIN COMPOSITION ON THE PROPERTIES OF THE HEAT-RESISTANT BASALTIC CONCRETE

Objectives. The optimal granulometric composition of filler compound ensures the production of concrete having improved physical and mechanical characteristics, as well as minimal binder consumption. The properties of heat-resistant concrete largely depend on the type and the ratio of its components. Taking this into account, the aim of the study is to determine the optimal grain composition of heat-resistant concrete.Methods. Methods for optimising the properties of heatresistant basaltic concrete with a composite binder and mechanochemical activation of the filler grains were used during the course of the research.A simplex-centroid experiment design is applied for this purpose. The composite binder was subjected to mechanochemical activation. Samples were made by vibration-pressing from a concrete mix with a cone draught of 2 cm.Results. The grain composition of heat-resistant concrete is proved to be the most important variable factor, regulating which the properties of concrete can be varied. The compositions of heat- resistant basaltic concrete with activated composite binder having a maximum application temperature of 700 ºС are developed. The influence of the grain composition of the basaltic filler on the properties of basaltic concrete using mathematical experiment planning methods is determined. The regression equations for the ultimate tensile strength and bending stress of basaltic concrete are obtained for heating temperature of 700ºC.Conclusion. The granulometric composition of heat-resistant basaltic concrete based on the activated binder is optimised for basic physical and technical properties. The optimal granulometric design of the composition of heat-resistant concrete indicates that as the coarse fraction (particles greater than 0.63 mm) in the filler composition increases, the ultimate tensile strength and bending stress of heatresistant basaltic concrete is increased when heated to a temperature of 700ºС. This is due to a more compact arrangement of sand grains