Nano technology in civil field has proved to make the construction faster, cheaper, safer and more varied. Automation of Nano technology construction can allow for the creation of structures from advanced home to skyscrapers much more quickly and efficiently. Amorphous nano-silica (nS) particles were incorporated in cement concrete, and their effect on the fresh state behavior was analyzed. Nano concrete is defined as a concrete made by filling the pores in traditional concrete using nano particles of size <500nano meters. Nano particles of silica turn into nano particles of cement (nano cement) in the chemical reactions that take place in the concoction of the concrete.When concrete is reduced to Nano level its properties are strongly influenced so that it increases their strength & durability. Addition of nano silica to the concrete leads to improve the material passing which results in the densifying of micro & Nano structures. In this project, Nano-silica has been replaced in various proportions such as 5%, 10%, 15% and 20% to the weight of cement. Then the mechanical properties of concrete such as compressive strength, tensile strength and flexural strength of the respective specimens were tested after 7 days and 28 days curing. Results have been obtained and compared with conventional concrete mix. Nano concrete was concluded to have a higher strength than the ordinary concrete.