ASSESSMENT OF THE INFLUENCE OF FINE GROUND SLAG ON THE PROPERTIES OF COMPOSITE GYPSUM BINDING AGENT

The article discusses the main aspects of changing the properties of a composite gypsum binder with a mineral slag additive when its fineness of grinding changes. The research consisted in grinding the slag to different specific surface area, followed by the determination of physical characteristics. In the course of the research, the kinetics of grinding, the change in specific surface area and the kinetics of heat release of finely ground slag during interaction with water were studied. Its rational amount has been revealed to ensure regulation within the recommended limits of CaO concentration in the gypsum cement system (according to TU 21-31-62-89). The acid-base properties of finely ground slag with different specific surface area are analyzed and a change in the concentration of active adsorption centers on the surface of its particles is established. The paper presents a comparison of the physico-mechanical characteristics of KGV, and reveals the features of the introduction of a mineral component with a different specific surface area of particles. It has been established that when slag is ground, particles are destroyed with an increase in the fine fraction of isometric grains with a large number of structural defects in the area of chips and gouges, with a highly developed surface, which contributes to the manifestation of chemical activity in the presence of water. The presence of adsorption centers on the surface of finely dispersed slags with different specific surface area in the area of the CR: 2...3.5; 7...9 and 10.5...13, increase their activity, contributing to an increase in the strength of KGV, which is confirmed by the results of physico-mechanical properties.