Blended Portland cements are hydraulic cements in which a well-defined fraction of the Portland cement clinker is replaced by other hydraulic, pozzolanic or non-hydraulic materials. Their general behaviour is similar to that of Portland cement since they harden when mixed with water and form the same calcium silicate hydrates (C-S-H) and calcium aluminate hydrates (C-A-H). The addition of supplementary cementitious materials (SCMs), such as metakaolin to cement generally improves workability, durability, and long-term strength. However, use of SCM concrete is sometimes limited due to a lack of understanding about material behaviors and a lack of proper specifications for its construction practice. In this paper the hydration of OPC in the presence of 30% metakaolin and 0.8% superplasticizer was monitored as a function of time with the help of heat evolution calorimeter, X-ray diffraction and SEM studies. Water consistency, setting time and compressive strengths were measured. Results have been discussed.