Both are SCM cements with similar durability/low-heat benefits and curing dependence; choose by the available SCM (slag → PSC IS 455, fly ash → PPC IS 1489) and the specific durability/heat target.

IS 455:2015 — Portland Slag Cement — Specification

IS 455:2015 — Clause S

Selecting PSC vs OPC vs PPC (Fitness for Purpose)

PSC is the right choice for severe sulphate/chloride exposure, mass and low-heat applications, and durability-governed work — given proper curing and acceptance at age. OPC (IS 269/IS 8112) suits where early strength/fast cycles govern; PPC (IS 1489) is the fly-ash-pozzolana alternative for similar durability/economy aims. Cement selection is fitness for the governing requirement.

Key Requirements

•Severe sulphate/chloride exposure, marine, aggressive ground → PSC (or SRPC IS 12330 for sulphate-specific)
•Mass / thick / hot-weather, durability-governed → PSC (low heat) with the IS 457 controls where mass
•Early strength / fast formwork cycle / precast → OPC (IS 269/IS 8112/IS 12269)
•Similar durability/economy via fly ash → PPC (IS 1489) — the pozzolanic analogue
•Durability still = cover + W/C + curing regardless of binder

Practical Notes

✓PSC is a deliberate durability/chemical-resistance/low-heat choice — for aggressive exposure and mass work it outperforms OPC at the specified age.

✓PSC and PPC are the two main SCM cements — pick by available SCM (slag vs fly ash) and the durability/heat target; both reward curing.

Common Mistakes

⚠Defaulting to OPC where PSC's chemical resistance/low heat is the better fit.

⚠Using PSC where genuine early strength governs (then blaming PSC).

⚠Treating cement choice as habit rather than fitness for the governing requirement.

Frequently Asked Questions

Related Resources

Cl. principle Cl. behaviour Cl. physical

View all 5 clauses of IS 455:2015 →