Introduction. At present, chemical modifiers are widely used in concrete technology, most of which are complex. The development of the theory and practice of high-strength concrete of the new generation has entailed the development and implementation of complex organomineral additives, which include modern superplasticizers (SP) and finely ground mineral fillers. High-strength concretes are multifunctional concretes that combine, along with high strength, other important properties – high frost resistance, water resistance, elastic-plastic properties, etc. Materials and research methods. Achieving high concrete performance is possible through the use of superplasticizers in combination with finely ground microfillers – stone flour, including nanoparticles and dispersed reinforcement. In this article, the main task is to model the development of the microstructure of cement stone with organomineral additives. For this purpose, a model of the development of the microstructure over time was developed taking into account the possible mechanisms of the influence of components on the composition of hydration products and the nature of early structure formation. Results and discussion. It is shown that the analysis of structural topology and modeling of the processes of formation of the microstructure of filled cement compositions, carried out together with the analysis of hydration products and hardening kinetics, allow us to predict possible mechanisms of action of complex additives and, in a certain sense, to predict possible scenarios for the development of the microstructure of cement stone, which largely determines the main physical and chemical properties of concrete and its durability. Conclusion. Experimental studies have shown that the use of a mixture of microfillers made it possible to achieve a concrete compressive strength of more than 115 MPa on the 28th day of normal hardening, and the insertion of calcium silicate hydrous into the concrete mixture increased the early strength of the hardening composite.