Durability defines the suitability of concrete to preserve its structural performances fixed by the designers, over specified span of time, hence it plays a fundamental role in determining the service life of the structure. Durability of concrete is defined as its ability to resist weathering action, chemical attack, abrasion or any other process of deterioration. The concrete should be designed without deterioration. As a matter of fact porosity and permeability are the governing parameter which is held responsible for the performance of the concrete. Porosity is one of the major components of micro-structure of the cement system. It influences the strength and permeability of concrete. All aspect of strength is related to the total porosity. The pore structure development in the cement pastes tends to reduce the volume of large pores during the initial stage of hydration. The presence of entrapped air capillary porous and estimated air in concrete could influence the strength properties of concrete.