The chemical-mineralogical compositions and physic-chemical properties of slag waste from the Angren TPP and Uzmetkombinat JSC were determined. A Conclusion was issued on their suitability for use as additives in cement and the possibility of using them for producing new types of hybrid additives for the production of composite Portland cements. With different combinations and ratios of Portland cement clinker, natural gypsum stone, and hybrid additives, the compositions of composite Portland cements were obtained and optimized, and Conclusions were issued on their compliance with the requirements of the Standard of the Republic of Uzbekistan Uz DSt 2830:2014 "Portland cement with composite additives. Specifications".

The possibility of improving the physical and mechanical properties of Portland cement with maximum clinker savings by optimizing the composition of hybrid additives is shown. It has been established that hybrid additives combining local mineral ingredients with the additive of artificial origin Phosfozol allow saving low-clinker Portland cement while maintaining its original grade 400.