Abstract:

In this paper, the effect of the pretreatment of silica fume on the mechanical properties of cement-based materials was discussed to prepare high-performance cement-based materials, and the corresponding mechanism was analyzed. The results show that the mechanical properties of cement-based materials improve after the pretreatment of silica fume, the compressive strength and the flexural strength respectively being more than 200 MPa and 30 MPa. Moreover, according to the calculated results obtained via the Aim-Goff model and the tested results of particle size distribution test, it is concluded that the pretreatment of silica fume disperses the agglomeration of silica fume and increases the filling index of the system, thus improving the density of the material. It is also indicated from SEM and XRD results that the pretreatment of silica fume improves the strength of the cement-based material because the structure of the interface transition zone through the dispersion of silica fume is improved. In addition, how to overcome the strong agglomeration effect and to improve the dispersion of silica fume nano-particles are the key to the full utilization of physical and chemical performances of silica fume.

Key words: high-performance cement, mechanical property, silica fume, dispersion, filling index, interface transition zone