Title: Influence of TiO2 Nanoparticles on Early C3S Hydration

Author(s): B.Y. Lee, J.J. Thomas, M. Treager, and K.E. Kurtis

Publication: Symposium Paper

Volume: 267

Issue:

Appears on pages(s): 35-44

Keywords: Avrami model; kinetics; modeling; nucleation; titanium dioxide.

DOI: 10.14359/51663281

Date: 10/1/2009

Abstract:
The effect of nano-anatase titanium dioxide (TiO2) powder on early age hydration kinetics of tricalcium silicate (C3S) was investigated. Isothermal calorimetry was performed on C3S pastes with 0, 10, and 15% of TiO2 addition by weight, and two mathematical models-the Avrami model and the boundary nucleation model (BN model)-were fitted to the data. The addition of TiO2 accelerated the rate of hydration, increased the peak reaction rate, and increased the degree of hydration at 12 and 24 hours. The model fits demonstrate that the BN model better captures the kinetics of the reaction, particularly in the deceleration period, than the Avrami model. The increase in the ratio of rate parameters (kB/kG) of the BN model with TiO2 addition suggests that hydration product is formed on or near the surfaces of TiO2 particles, as well as on the C3S surface. These results demonstrate that the addition of TiO2 nanoparticles accelerates the early hydration by providing additional nucleation sites, forming the foundation for future optimization of photocatalytic and other nanoparticle-containing cements.