Fresh properties, rheological behavior and structural evolution of cement pastes optimized using highly dispersed in situ controllably grown Nano-SiO2

Abstract

Nano-SiO2 (NS) is an attractive candidate for use as a nano reinforcement in cement. However, one of the biggest obstacles to the application of NS is the difficulty in achieving good dispersion in the matrix, which seriously affects its working performance. In this paper, a novel method was used to prepare composites by directly in situ growing NS (INS) on the surface of iron tailings powder (ITP) to tailor the dispersion in cement, simultaneously effectively controlling the particle size and the amount of growth of NSs. To this end, we propose the growth mechanism of INS and evaluate its dispersibility. Compared with NS, INS can better maintain a good fresh property and rheology. The agglomerated NS become weak regions in the matrix, while the ITP matrix of INS produces a rigid system, which also maintains the long-term enhancement effect. This work has opened a new strategy to develop NS as a nano reinforcing material for cement composites and has great potential to improve the efficiency of ITP utilization.