IS 1489:2023 Part 1 is the Indian Standard (BIS) for portland pozzolana cement - part 1: fly ash based - specification. This standard covers the manufacture, physical, and chemical requirements for fly ash-based Portland pozzolana cement (PPC). It establishes the permissible limits for fly ash addition (15% to 35%) and details the necessary testing criteria to ensure strength, durability, and reduced heat of hydration for construction applications.
Specifies requirements for fly ash based Portland pozzolana cement, promoting use of industrial by-products in construction.
Fly-ash blended Portland Pozzolana Cement — composition limits, strength gain, fineness, setting times and durability advantages over OPC.
| Reference | Value | Clause |
|---|---|---|
| Fly ash content (range, by mass of cement) | 15 – 35 % | Cl. 5.1 |
| 28-day compressive strength (min) | 33 MPa | Cl. 6.2 (Table 4) |
| 7-day compressive strength (min) | 22 MPa | Cl. 6.2 (Table 4) |
| 3-day compressive strength (min) | 16 MPa | Cl. 6.2 (Table 4) |
| Fineness — Blaine specific surface (min) | 300 m²/kg | Cl. 6.1.1 |
| Soundness — Le Chatelier (max) | 10 mm | Cl. 6.1.2 |
| Soundness — autoclave (max) | 0.8 % | Cl. 6.1.2 |
| Initial setting time (min) | 30 minutes | Cl. 6.1.3 |
| Final setting time (max) | 600 minutes | Cl. 6.1.3 |
| Drying shrinkage (max) | 0.15 % | Cl. 6.1.4 |
| MgO (max) | 6.0 % | Cl. 5.2 (Table 1) |
| SO₃ (max) | 3.0 % | Cl. 5.2 (Table 1) |
| Loss on ignition (max) | 5.0 % | Cl. 5.2 (Table 1) |
| Total chloride (max) | 0.05 % | Cl. 5.2 (Table 1) |
| Reactive silica content of fly ash (min) | 20 % (Class C/F per IS 3812-1) | Cl. 5.1 |
| Heat of hydration — 7 days (max) | 275 kJ/kg (typical lower than OPC) | |
| Sulphate resistance — improved vs OPC | Better; suitable for moderate sulphate exposure | Annex A (Cl. A-2.3) |
| Alkali-silica reactivity — protective effect | Yes (with reactive aggregates) | Annex A (Cl. A-2.4) |
| Standard bag mass | 50 kg ± 2 % | Cl. 9.1 |
| Recommended w/b for similar workability vs OPC | Slightly higher (5–10 % more water) |
IS 1489 Part 1 (2023) provides Specifications for Portland Pozzolana Cement (PPC) — Part 1: Fly Ash Based — the IS code for fly-ash-blended Portland cement, India's most-used cement type. PPC blends OPC clinker with fly ash to reduce CO₂ emissions, improve durability + reduce cost compared to plain OPC.
Use IS 1489 Part 1 when you are: - Specifying PPC for routine RCC construction - Doing DPR for projects requiring sustainable cement choice - Specifying mass concrete (PPC has lower heat of hydration) - Working in sulphate / aggressive environment (PPC has better resistance than plain OPC) - Procurement / acceptance testing of PPC - Cross-referencing with IS 10262:2019 mix design + IS 456:2000
What IS 1489 Part 1 covers: - PPC composition (clinker + fly ash + gypsum) - Fly ash quality (per IS 3812-2019) - Chemical + physical requirements - Strength specifications - Setting time + soundness - Heat of hydration - Storage + acceptance
PPC characteristics: - Composition: clinker 65-80 % + fly ash 15-35 % + gypsum 3-5 % - Strength class: generally 33 grade (matches OPC 33); some 43 grade available - Lower heat of hydration (vs OPC) - Better long-term strength (continues to gain over months) - Lower cost than OPC (cement replacement by fly ash) - Improved durability in aggressive environments - Reduced shrinkage cracking - CO₂ reduction: 25-35 % vs plain OPC
When to use PPC: - Routine RCC (most applications) - Mass concrete (foundations, large pours) - Marine + sulphate-aggressive environments - Where lower heat is beneficial - Sustainability-focused projects
When NOT to use PPC: - Very high-strength concrete (M50+; OPC 53 preferred) - Rapid construction (PPC slower setting) - Low temperature curing (slower hydration) - Where time-critical (per setting time requirement)
Chemical composition: - Lime (CaO): 50-60 % (lower than OPC due to fly ash) - Silica (SiO₂): 25-35 % - Alumina (Al₂O₃): 5-10 % - Iron oxide (Fe₂O₃): 3-6 % - MgO: ≤ 6 % - SO₃: ≤ 3.5 % - Insoluble residue: ≤ 40 % (accommodates fly ash content) - Loss on ignition: ≤ 5 % - Chloride content: ≤ 0.1 % - Alkali (Na₂O eq): ≤ 0.6 % (for sensitive applications)
Fly ash content: - 15-35 % by mass of total binder - Class F fly ash per IS 3812-2019 (low-lime; pozzolanic) - Higher percentage for sustainability + low-heat applications - Lower percentage for strength-critical applications
Physical properties: - Fineness (Blaine): ≥ 225 m²/kg (preferred 300+) - Initial setting time: ≥ 30 minutes - Final setting time: ≤ 10 hours - Soundness (Le Chatelier): ≤ 10 mm - Soundness (autoclave): ≤ 0.8 %
Strength requirements: - 3-day strength: ≥ 16 MPa - 7-day strength: ≥ 22 MPa - 28-day strength: ≥ 33 MPa (Grade 33 PPC) - Higher grade PPC available: 43 MPa at 28 days
Long-term strength gain: - PPC continues to gain strength beyond 28 days due to pozzolanic reaction - 90-day strength: typically 15-20 % higher than 28-day - 1-year strength: typically 25-30 % higher than 28-day - Design for 28-day; long-term gain is bonus
Heat of hydration: - 7-day: ≤ 250 kJ/kg (lower than OPC's 295 kJ/kg) - 28-day: ≤ 290 kJ/kg - Advantage for mass pours
Setting + workability: - Slightly slower setting than OPC (due to lower lime + slower fly ash reaction) - Better workability - Less sticky / harsh mix - Compaction + finishing easier
Strength specifications: - PPC Grade 33: ≥ 33 MPa at 28 days (most common) - PPC Grade 43: ≥ 43 MPa at 28 days (premium) - Mass concrete pours: consider 90-day strength for design
Mix design with PPC (per IS 10262:2019): - W/C ratio: 0.40-0.50 typical (slightly higher than OPC for same strength) - Cement content: 320-400 kg/m³ - Fly ash content in mix: 0-30 % cement replacement (in addition to PPC's intrinsic fly ash) - Plasticizer / admixture for workability + lower W/C - Slump: 75-150 mm - Trial mix mandatory
Production: - Major Indian manufacturers: UltraTech, ACC, Shree, Ambuja, etc. - Multi-state cement plants - Bagged (50 kg) or bulk supply - 3-month shelf life
Acceptance testing: - Per shipment / per consignment - Sample: representative - Test per IS 4031 + IS 4032 - NABL-accredited lab
Test schedule: - Setting time + soundness on receipt - 3, 7, 28-day cube strength - Optional: 90-day cube (for mass concrete) - Fineness + chemical periodic
Acceptance: - All parameters within IS 1489 Part 1 + IS 3812-2019 limits - 28-day strength ≥ design (33 MPa for PPC 33) - Strength gain consistent - Workability acceptable
Rejection: - Any parameter below spec - 28-day strength < 32 MPa (5 % tolerance) - Setting time outside range - Soundness fail - Chloride / alkali excessive
Storage: - Dry; weather-protected - Off-ground (10-15 cm) - Max 10 bags stacked - First-in-first-out - 3-month shelf life
Construction considerations: - Slower setting: plan placement + finishing accordingly - Slower early strength: form-stripping delayed (per IRC:85:1983 accelerated testing if needed) - Long-term strength gain: consider for design + load testing - Heat of hydration: advantage for mass pours - Sulphate / chloride resistance: advantage in aggressive environments
Environmental benefits: - 25-35 % CO₂ reduction vs plain OPC - Industrial waste utilization (fly ash) - Reduced cement mining - Lower embodied carbon
Comparison with alternatives: - OPC 33: lower strength + cost - OPC 43: same strength as PPC 43; higher heat - OPC 53: higher strength; for premium applications - PSC (IS 455): slag-blended; alternative blended cement - SRC: sulphate-resistant; for chemical exposure
Modern composite cements: - OPC + Fly ash + Slag (composite): new IS standard (IS 16415); even better performance - Carbon-neutral cement: future direction - Self-healing cement (research)
1. PPC stored wet. Moisture affects pozzolanic activity. Strict dry storage. 2. Old PPC used. Aged beyond 3 months; reduced reactivity. Verify production date. 3. Mix design assumes OPC. PPC behavior different; results vary. PPC-specific mix design. 4. Form stripping too early. PPC slower hydration; insufficient strength at standard time. Wait per actual strength. 5. No 90-day strength consideration. Mass pour designed for 28-day; PPC continues to gain. Use 90-day for design. 6. Setting time inappropriate for application. PPC slower; placement window may be tight. Per IS 1489 Part 1. 7. Fly ash quality unknown. Source variable; affects PPC quality. Manufacturer source qualified. 8. Sulphate aggressive environment. PPC better than OPC but not as good as SRC for severe exposure. Match cement to environment. 9. Cold weather curing. PPC slower hydration in cold; further delay. Per IRC:74:1979 modified. 10. Soundness fail. Expansion; structural concern. Test per IS 4031 + IS 1489 Part 1. 11. Chloride content not verified. RCC corrosion risk. Per spec. 12. No site testing. Cement quality assumed. Sample testing on receipt. 13. Mix water quality. Salts affect cement; reduced strength. Per IS 456. 14. Curing inadequate. Pozzolanic reaction needs water for long-term. 14+ day curing preferred for PPC. 15. Adverse reaction with admixtures. Plasticizer-PPC incompatibility. Trial mix mandatory. 16. Storage too long. Reactivity lost. 3-month shelf life strict. 17. No alkali check. ASR risk with reactive aggregates. Test combined. 18. Heat of hydration over-estimated. Designer assumes high heat as OPC; conservative + costly. Use PPC actual heat values.
PPC concrete project — IS 1489 Part 1 touchpoints:
1. Specification: - PPC selected for sustainability / cost / durability - Source qualified - Sample testing pre-procurement - Acceptance criteria documented
2. Mix design (laboratory): - Target strength per IS 10262:2019 - PPC-specific design considerations - Cement + W/C + aggregate proportioning - Trial mixes + cube tests at 7, 28, 90 days - Workability + finishing verification - Final mix proportion
3. Procurement: - Per design specification - Quantity per project schedule - Storage facility prepared
4. Site reception: - Sample testing on receipt - Verification of production date - Quality control on each consignment - Storage in proper conditions
5. Construction: - Mix per design - Concrete placement + compaction + curing - Adequate curing time (14+ days for PPC) - Cube sampling per IS 1199 - QC documentation per pour
6. Quality control + acceptance: - 28-day cube strength per design - 90-day strength (for long-term verification) - Concrete quality verification - Compliance with IS 456 + IS 1489 Part 1
7. Long-term: - Continued strength gain (pozzolanic reaction) - Improved durability in aggressive environments - Reduced shrinkage cracking - 75+ year concrete service life with proper specification
IS 1489 Part 1 is the sustainable cement reference for India — applied on routine RCC, mass concrete, marine + aggressive environment projects, and increasingly on Smart City / sustainable infrastructure initiatives.