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PPC Principle & Parts (Fly Ash vs Calcined Clay) IS 1489 specifies Portland-Pozzolana Cement (PPC) — OPC clinker blended with a reactive pozzolana that consumes the lime (CH) freed by clinker hydration to form extra binding C-S-H. Part 1 is fly-ash-based PPC (the dominant one in India), Part 2 is calcined-clay-based. Same pozzolanic principle, different supplementary material; specify the correct part and the current edition.
Key Requirements • PPC = OPC clinker + reactive pozzolana (Part 1 fly ash / Part 2 calcined clay) within the specified proportion• Pozzolanic reaction: pozzolana + clinker-derived CH → additional C-S-H (denser, lower-permeability matrix)• Cite the correct part (1 fly ash / 2 calcined clay) and the current edition (withdrawn editions invite disputes)• Pozzolana quality is fundamental — Part 1 presumes IS 3812 fly ash; Part 2 a conforming calcined clay (IS 1344)• Read with the cement-spec family — OPC IS 269/IS 8112, slag IS 455Reference Tables IS 1489 parts
Part Pozzolana Note Part 1 Fly ash (IS 3812) Dominant PPC in India Part 2 Calcined clay (IS 1344) Used where fly ash scarce / LC3-type interest
Cite the exact part and the current edition; older editions are withdrawn.
Practical Notes ✓ PPC is one of the most-used Indian binders for sound reasons — durability, lower heat, economy/embodied-carbon from clinker substitution.
✓ Specify the correct part and current edition; performance presumes a conforming pozzolana (IS 3812 fly ash / IS 1344 calcined clay).
Common Mistakes ⚠ Citing a withdrawn edition or the wrong part (fly ash vs calcined clay).
⚠ Assuming any pozzolana works — quality (fineness/LOI for fly ash; calcination for clay) is fundamental.
⚠ Treating PPC as merely 'cheaper OPC' rather than a different hydration system.
Frequently Asked Questions What is the difference between IS 1489 Part 1 and Part 2? ▾
What makes PPC different from OPC? ▾
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Cl. 6
Chemical Requirements & Pozzolana Proportion