EXPERIMENTAL INVESTIGATION ON DURABILITY PROPERTIES OF CONCRETE ADDED WITH NANO SILICA

The study examined the durability properties of concrete added with Nano-silica. Lifeline buildings and other infrastructures have highlighted concrete durability issues. The use of nanoparticles in materials based on cement has been recently attractive because of the unique properties at Nano-level that they are able to achieve. This can be prominently utilized in enhancing the ductility of cement-based composites which are generally brittle, also cracks at the nanoscale could be arrested by incorporating carbon nanotube or carbon nanofiber. Nano-silica has a unique advantage in the potential pozzolanic-reaction with cement hydration products over other nanoparticles. Addition of Nano-silica is known to redefine pore size and distribution which would alter the durability of the concrete. Durability properties were tested by checking how concrete of grade M30, with 2% by weight of its cementitious materials replaced with Nano-silica, withstands in alkali environment, acidic environment, sulphate environment, and in a water curing in comparison to conventional concrete of M30 grade in respective environments. The Nanofiller effect and the pozzolanic-reaction increased the homogeneity of the microstructure and the porosity, particularly at the Interfacial Transition Zone, which decreased the permeability of deteriorating gases. Durability tests validated the positive effects of Nano-silica added to concrete. The distribution of pore size also showed that Nano-silica refined the large capillary pores, subsequently decreasing the permeability nature of concrete, enhancing its durability. Also, Nano-silica added concrete mix shows increased compression strength, tensile strength, and flexural strength compared to the conventional concrete mix.