Cement is a binding material that is used to bind different aggregate (coarse and fine) through a chemical process known as hydration in the presence of moisture. This research work is planned with the purpose to determine the most appropriate and efficient proportions of admixture i.e. fly ash so as to modify the strength properties of concrete. By adding this admixture strength properties of cement and concrete can be enhanced. Cement be replaced with different percentages levels of Fly ash as 0%, 10%, 20%, 30%, 40% and 50% by weight of cement. To work out the strength properties and the variation pattern due mixing in different proportions of fly ash for different tests such as compressive and tensile strength are planned to be performed after 7, 14, 21 and 28 days curing. These experiments were conducted at Laboratory scale. Addition of fly ash as an admixture in replacement of cement enhanced strength properties of cement and concrete up to a limit. At 10% fly ash cured for 28 days maximum compressive and tensile strength was achieved i.e. 1170 psi and 66 psi respectively. Furthermore, addition of fly ash as cement replacement showed gradual reduction in the strength properties i.e. minimum compressive and tensile strength was found to be for 50% fly ash sample cured for 7 days. As an outcome of this research fly ash is concluded to be an effective replacement of cement for non-loading constructions.