Influence of nanosized silicon dioxide on the properties of cement stone matrix: synthesis methods and experimental results

Abstract

The results of experimental studies on the effect of nanosized silicon dioxide powder synthesized by different methods (sol-gel, high-energy electron beam and arc plasma evaporation methods) on the structure and physical-mechanical properties of cement compositions are presented. It is shown that the purity of nanosilicon dioxide has a significant effect on the properties of cement stone in the initial setting time. It is established that nano-SiO₂ synthesized by arc plasma evaporation allows increasing the entire system reactivity, which is a consequence of higher strength characteristics and the hydrophilic properties of cement, providing plasticizing properties of the binder. The matrix framework of the modified cement stone predominantly represents needle-shaped crystals of low-basic calcium hydrosilicate C‑S-H (1) ranging in the size from 3 to 20 µm. This structure allows forming a reinforced matrix framework of cement stone and thus increasing the bonding between particles. Modification of cement stone with nano-SiO₂ at a concentration of 0.03 wt.% allows achieving a strength increase of up to 40%.