INVESTIGATION OF MECHANICAL AND PHYSICAL PROPERTIES OF MORTARS CONTAINING SILICA FUME AND NANO-SIO2

It has been found that physical properties of concrete, particularly strength and permeability significantly depend on its pore structure. Ultra fine particles of nano- SiO2 fill the voids of CSH structure and provide more homogenous distribution of hydrated products. This effect of nano-SiO2 enhances the durability of cement composites as well as the strength. In this paper, influence of nano-SiO2 on different properties of cement mortar was investigated in comparison with silica fume (SF) as a well-known active pozzolan. Different amounts of nano-SiO2 (0, 1%, 3%, 5%, 7%and 9%) were incorporated into the ordinary cement mortar. Mechanical properties, shrinkage, water absorption of the specimens were determined. Results showed that the optimal content of Nano-SiO2 in plain cement mortar was around 7%. Nano-SiO2 particles were more effective in developing higher mechanical strength and lower water absorption than that of SF. Yet the mortar containing nano-SiO2 experienced higher shrinkage than that of SF mortar.

کلیدواژه ها:

cement mortar ، mechanical properties ، nano-SiO2 ، silica fume ، shrinkage