Review article

The research considers the features of the influence of nano-, ultra- and micro-additives based on SiO2 on the processes of hydration, setting, structure formation and strength gain of cement hardening systems. There was used a complex nano-scale additive based on silicon dioxide, sodium liquid glass and metakaolin. It is established that the additives used accelerate the processes of setting and hydration of cement hardening systems. The start time of setting of all modified cement systems is 210 minutes with the corresponding values of plastic strength of 577-582 kPa. Concurrently, the cement system, modified with a complex nano-scale additive based on silicon oxide after 28 days of hardening is characterized with the highest value of the hydration degree (93 %), as well as it has the high strength indicators throughout the entire hardening time (65 and 93 MPa on the 1-st and 28-th day, respectively), which is due to the formation of low- and high-base calcium hydro-silicates of various morphologies capable of forming a dense, amorphous-crystalline structure.