What is the permissible percentage of fly ash in PPC?

According to the standard, the fly ash content must be between 15% and 35% by mass of the Portland-Pozzolana Cement.

What is the minimum initial setting time for fly ash based PPC?

The minimum initial setting time is 30 minutes, which is identical to standard OPC.

What is the minimum required compressive strength at 28 days?

The minimum 28-day compressive strength requirement is 33 MPa.

IS 1489 Part 1

: 1991

Portland-Pozzolana Cement - Part 1: Flyash Based - Specification

CurrentEssentialSpecificationMaterials Science · Concrete

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This standard specifies the physical and chemical requirements, manufacturing process, and testing for flyash-based Portland-Pozzolana Cement (PPC). It sets the acceptable range for flyash inclusion, setting times, soundness, and required compressive strength milestones to ensure long-term durability in concrete structures.

Specifies requirements for fly ash based Portland-Pozzolana Cement.

Quick Reference Values

fly ash content min15%

fly ash content max35%

fineness blaine min300 m2/kg

initial setting time min30 minutes

final setting time max600 minutes

compressive strength 3 days min16 MPa

compressive strength 7 days min22 MPa

compressive strength 28 days min33 MPa

Practical Notes

PPC develops early strength slower than Ordinary Portland Cement (OPC), so formwork removal might need to be delayed compared to OPC.

PPC has a lower heat of hydration, making it ideal for mass concrete works and minimizing thermal cracking.

Concrete made with PPC requires extended curing periods to fully leverage the secondary pozzolanic reactions for maximum durability and strength.