Preparation of nano cement particles by wet-grinding and its effect on hydration of cementitious system

Abstract In this study, nano cement particles (Nano-C) were prepared via wet grinding cement. Nano-C was characterized by laser particle size distribution, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and 29Si magic-angle spinning nuclear magnetic resonance (29Si MAS NMR). The particle size of Nano-C was D50 = 53.1 nm. In order to disperse the nano particles, polycarboxylate superplasticizer was used in the process of grinding. The results show that 0.5%, 1.0%, 2.0%, and 4.0% Nano-C could increase the 12-h compressive strength by 49%, 109%, 194% and 197%, in comparison with the reference. The influence of Nano-C on the hydration, hydration products, microstructure was tested by means of hydration heat, chemical shrinkage, XRD, Thermogravimetric analysis (TGA), SEM, 29Si MAS NMR, and Mercury injection porosimetry (MIP). The results revealed that Nano-C not only used as distinguished nucleus seed to enhance the PC system hydration but also exhibited high hydration activity to produce C-S-H gel to further raise the PC hydration up. These findings provided a novel way to prepare nanomaterials, which was expected to provide a way to improve the early strength of precast concrete.