Portland Slag Cement(PSC)
PSC also called Blast furnace slag cement or simply slag cement is obtained by mixing Portland cement clinker, gypsum and GGBFS in suitable proportions and grinding the mixture of the constituents. It may also be obtained by separately grinding portland cement clinker,gypsum and slag mixing them together.
The quantity of granulated slag mixed with Portland cement clinker will range from 25% to 65%.In PSC early strength is mainly due to the Portland Cement clinker fraction.It has generally be observed that the rate off the rate of hardening PSC cement is somewhat slower than OPC.
This is however , to be noted that proper quality of slag i.e GGBFS is to be used and not air cooled crystallized slag.
- In mass concreting minimize the risk of early age thermal cracking.
- Acombination of 70% GGBFS and 30% OPC is recommended for resistance of cement to chemical particularly acid attack.
- It is recommended for use in water retaining structure.
- GGBS concrete perform better in aggressive water environment such as in concrete foundation.