Rapid Hardening Cement (RHC)

Rapid Hardening Cement (RHC)

It is also called Early Strength Cement because its 3 days strength is almost equal to 7 days strength of OPC. It is different from quick setting cement which only sets quickly whereas in RHC, strength development is very fast. This is because of following reasons:

(1)Higher fineness of cement. The specific surface of this cement is increased to 320 m2/kg as compared to 225 m2 /kg for OPC.

(2)Higher quantity of C3S in cement as compared to C2S. C3S is more reactive in comparison to C2S.

As a result of these changes, the rate of reaction in the early period is considerably increased and so is the heat generated. Therefore, this cement should be used only where the early strength requirement is there. At the same time it should not be recommended where surface/volume ratio is less and the large heat that will be librated, may not be dissipated effectively. If it is not ensured then there are chances of temperature cracks.

This cement is recommended :

(1)In pre-fabricated construction

(2)When the form work is to be removed early

(3)In road repair works(4)In cold weather where heat generation will be helpful in preventing freezing.