IntroductionConcrete is the most widely used material for various applications in this world. India is the world's second largest producer of concrete. As this is used in various applications, its basic properties obtained by preparing concrete with the required raw materials need to be enhanced by adding another material to it. Next comes the role of admixtures through which the required properties can be extracted from the concrete. There are two basic classifications of adjuvants. Chemical and mineral adjuvant. There are different types of mineral admixtures. Most mineral admixtures are by-products available from certain manufacturing industries. Silica fume is a mineral additive obtained as a by-product of the silicon industry. It is a most expensive material but is a very desirable material for normal concretes. The imprint of nanotechnology, defined as the science of controlling properties at the nanoscale, capable of bringing revolutionary changes to the properties of bulk materials [23] in the field of construction, has a great impact on the improvement of concrete properties. There are many types of nanomaterials like nano-silica, nano-alumina, carbon tubes, etc. This article describes how the properties of concrete are improved by adding nano-silica and compares them with concrete containing microsilica. Nano-silica and micro-silica are silica adjuvants having higher contents of amorphous silica, but nano-silica is that having a size of 1/10th of silica fume, which constitutes a major advantage for nano -silica to improve the various properties of concrete to a greater extent. than microsilica.Silica fume It is a by-product of the silicon industry and contains very large amounts of amorphous silicon dioxide (about 90%). (ACI-116R)[1] It is 100 times smaller than cement...... middle of paper ...... may be due to the reduced size and total volume of pores. Little difference was found between adding NS or MS to these concretes.[16]Effect on self-compacted concreteWhen adding NS to self-compacted concrete, a reduction in bleeding, segregation and fluidity. Experimental results showed improved compressive strength, split tensile strength and flexural strength. Higher electrical resistivity and chloride ion penetration resistance were also observed in self-compacting concretes incorporated with NS. Effect on eco-concretesDelayed setting and very low initial strengths are major defects of eco-concretes which can be compensated by incorporating NS into these concretes.. [20]