In-situ dispersion of nano-TiO2 to highly reinforce cement paste

Regardless of how good pre-dispersion of nano-TiO 2 in aqueous solutions, re-aggregation rapidly occurs once it is mixed into fresh cement mixtures, limiting the nano-reinforcing efficiency for cement-based materials. In this study, an in-situ release strategy by pre-encapsulating nano-TiO 2 in microscaled ice and post-dispersing into fresh cement matrix during ice-melting process was developed to highly reinforce the microstructure and properties of cement paste. Compared with the conventional dispersion strategy, a much better dispersion of nano-TiO 2 (0.6 wt% by cement) was achieved using the in-situ release strategy, which not only improved the 7- and 28-day compressive strength of cement paste by 9.2% and 10.1%, respectively, but also reduced the cement hydration heat and water adsorption by 36.1% and 4.6%, respectively. In addition to this, the NO degradation efficiency of cement paste was also improved by 20% due to the larger exposed surface area of nano-TiO 2 with better dispersion. These research outcomes demonstrate that the in-situ release strategy facilitates the dispersion of nano-TiO 2 in cement matrix and contributes to highly reinforcing cement paste with lower hydration heat and water adsorption, strong mechanical strength and higher photocatalytic properties.