Comparative Study on Microstructure and Durability of Concretes Containing Nano Silica and Silica Fume

Recently, Nanotechnology has caused a vast breakthrough worldwide and scientists in different fields have used it. Nano particles have been gaining increasing attention and been applied in many fields to fabricate new material with novel function due to their unique physical and chemical properties. Therefore, using Nano-silica as a Nano-scale additive in concrete is under further inspection by researchers. Recent contribution to the development of building materials compromise adding colloidal Nano-silica to concrete. In this paper, the influence of Nano-silica addition on mechanical and durability properties of concrete as compared with silica fume has been studied. Tests include compressive strength, water permeability, rapid chloride penetration and electrical resistance test. Moreover, microstructure of the cement paste incorporating Nano-silica and Silica-fume were studied through X-ray diffraction and Scanning electron microscope tests. The experimental results show that Nano-silica as an artificial pozzolanic material can improve the compressive strength, water penetration resistance and electrical resistivity of concrete and reduce the chloride diffusion more effectively than SF at early ages. In addition, utilizing NS in cement paste improve its microstructure at early days.