Cement is the most costly and energy intensive component of concrete. The unit cost of concrete can be reduced as much as possible by partially replacing cement with fly-ash and metakaolin. Fly-ash is a waste obtained during thermal industries. As fly-ash is a waste material leaving into the environment directly can cause environmental problem. Hence the reuse of waste material has been emphasized. Therefore scientific study should be made towards reuse both at an experimental phase and in practical application. In the present study M25 grade of reference concrete was prepared without any replacement in cement. The same grade was partially replaced by 20% of fly-ash and 0%, 5%, 10% and 15% of metakaolin in cement. Investigation was carried out for fresh concrete properties and hardened concrete properties on specimens cured for 7, 28 & 90 days.

Keywords : Index Terms— Concrete, fly-ash, metakaolin, fresh concrete, compressive, split tensile, flexural.