NANOSTRUCTURED COMPOSITE MATERIALS: FORMATION OF EARLY STRUCTURE AND STRENGTH

The current stage of development in the construction industry utilizes a large number of finely ground additives and nanotechnology. Nanotechnology allows for the creation of a wide range of building materials by manipulating both the external and internal structure of materials during production. Modified ultra-dispersed mineral additives allow for targeted influence on the processes of structure formation and hardening of cement mortars, thereby controlling the formation of early structure and strength. The formation of early structure and strength was studied by establishing the kinetics of initial structure formation based on the indicators of change in plastic strength (Ppl). The kinetics of nucleation of crystal hydrates in hardening cement paste was estimated using the Avrami-Erofeev model. In this work, the effect of an ultrafine complex additive (CA) consisting of ground limestone and a polycarboxylate-based superplasticizer was assessed. It has been shown that the complex additive leads to activation of the initial structure formation. Ultra-dispersed particles of the complex additive act as formed crystallization centers of phases. They increase the rate of formation of the cement stone structure and increase the plastic strength of the hardening system. Activation of the initial structure formation during cement mixing with stabilized limestone suspensions leads to an increase in the initial strength of the cement-sand mortar by 8-20%. This increase depends on the concentration of limestone in the suspension.