Features of Structure Formation Processes in the Phosphogypsum-Ground Granulated Blast Furnace Slag-Portland Cement System

In today's wartime, one of the key issues of Ukraine's construction industry is to rebuild road infrastructure. However, outdated approaches to the management of natural resources lead to their devastating depletion, slowing economic growth and the implementation of European construction standards. The direction of scientific research on the use of technogenic waste as a material resource in the road industry is relevant and progressive. The overall purpose of this work is to investigate the possibility of utilizing phosphogypsum by creating a composite material based on it for constructive layers of road pavement. The choice of components for the composite material was based on the principle of creating rigid mixtures based on raw phosphogypsum stabilized with mineral substances, namely ground granulated blast furnace slag and Portland cement, which corresponds to the concept of sulfate-alkaline activation of slag. The investigation of the phase composition and microstructure of the composite material indicates the formation of calcium hydrosulfoaluminate and calcium hydrosilicates in the cementing matrix. The formation of hydraulically active phases contributes to the gain of strength and frost resistance, and ensures the achievement of water resistance. It has been established that composite materials based on phosphogypsum correspond to the criteria of the national standard of Ukraine (DSTU 9177-3:2022 Part 3: Materials reinforced with mineral binders) for the constructive layers of road pavement.