¹H Low-Field NMR Relaxation Characteristics of Hydration Process of White Cement Modified with Silica Nanoparticles

¹H low-field nuclear magnetic resonance instrument was used to continuously monitor the changes in the transverse relaxation time of white cement with silica nanoparticles with different sizes (i.e., 15 nm, 50 nm and 100 nm) from adding water to hydration for 72 h. The effect of silica nanoparticles with different sizes on the hydration process of cement was investigated. The setting time of cement paste was measured using the Vicat apparatus. The results show that the crystal nucleation of silica nanoparticles can affect the early hydration process of cement, thus breaking the flocculation structure of cement paste due to the physical adsorption and pozzolanic reaction, reducing the number of macropores, and improving the uniformity of cement paste. In addition, the smaller the silica nano particles is, the less the free water content in hydration process and the shorter the setting time will be.