Nowadays, pozzolanic materials are widely used as supplementary cementing material in Portland cements and may replace part of the clinker in order to enhance the performance of the hydrated cement. Such composite or blended cements are employed for their economic, ecological and technological benefits. Energy consumption as well as CO2 emission is reduced. Supplementary cementing materials reduce lime content in hydrated Portland cements and replace it with pore-filling cement hydrates, which are known to improve the ultimate strength, impermeability and durability to chemical attack of cement.1Different types of additions are used such as pozzolanic (natural pozzolan, lowcalcium fly ash and silica fume), auto pozzolanic (high calcium fly ash and blastfurnace slag) and crystalline (generally known as filler). Pozzolanic activity orhydraulicity of pozzolanic material is mainly associated with their vitreous and/oramorphous structure....