IS 8112:2013 is the Indian Standard (BIS) for ordinary portland cement, 43 grade - specification. This standard lays down the specifications for 43 Grade Ordinary Portland Cement (OPC), covering its chemical composition and physical properties. It details mandatory requirements for strength, setting time, soundness, and fineness to ensure the cement's quality and performance in concrete construction.
Specifies requirements for 43 Grade Ordinary Portland Cement.
43-grade OPC strength bands, fineness, soundness, setting times, chemistry caps and packaging — the workhorse cement for general RCC.
| Reference | Value | Clause |
|---|---|---|
| 28-day compressive strength (min) | 43 MPa | Cl. 6.2 (Table 4) |
| 28-day compressive strength (max)— upper bound prevents over-strength control issues | 58 MPa | Cl. 6.2 (Table 4) |
| 7-day compressive strength (min) | 33 MPa | Cl. 6.2 (Table 4) |
| 3-day compressive strength (min) | 23 MPa | Cl. 6.2 (Table 4) |
| Fineness — Blaine specific surface (min) | 225 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 |
| Lime saturation factor (LSF) | 0.66 – 1.02 | Cl. 5.1 (Table 1) |
| Magnesia (MgO) — max | 6.0 % | Cl. 5.1 (Table 1) |
| Sulphuric anhydride (SO₃) — max | 3.0 % (C₃A ≤ 5 %); 3.5 % otherwise | Cl. 5.1 (Table 1) |
| Insoluble residue (max) | 4.0 % | Cl. 5.1 (Table 1) |
| Loss on ignition (max) | 5.0 % | Cl. 5.1 (Table 1) |
| Total chloride (max, by mass of cement) | 0.05 % (PCC) / 0.10 % (RCC) | Cl. 5.1 (Table 1) |
| Alkali (Na₂O equivalent, max — low-alkali option) | 0.6 % | Cl. 5.1 (Table 1) |
| Standard bag mass | 50 kg ± 2 % | Cl. 9.1 |
| Shelf life — design value | 3 months from date of manufacture | Cl. 10.3 |
| Heat of hydration (typical 7 d) | Higher than OPC 33 due to finer/clinker richness |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
IS 8112:2013 is the specification for 43-grade Ordinary Portland Cement — OPC whose 28-day standard-mortar compressive strength is ≥ 43 MPa. It is the general-purpose structural cement for the bulk of ordinary RCC and building work: enough strength for typical M20–M35 concrete, with less heat and (often) better economy/durability behaviour than over-using 53-grade.
It sits in the OPC family:
OPC 43's 28-day mortar strength is ≥ 43 MPa (IS 4031 on IS 650 sand), sitting between OPC 33 and OPC 53:
The engineering point: cement selection is fitness for the governing requirement. For most ordinary RCC, OPC 43 *is* the sensible default — reserve OPC 53 for where early strength/high grade truly governs, and use PPC/low-heat where durability or heat governs.
Scenario: typical building RCC, M25–M30, normal sections, moderate exposure.
Step 1 — default to 43-grade: OPC 43 (IS 8112) meets M25–M30 with margin and lower heat than 53 — the sensible default unless something specific overrides.
Step 2 — when to deviate: *early strength governs* (precast/fast cycle) → OPC 53; *durability/heat governs* (aggressive exposure, thick pours) → PPC/slag/low-heat. Otherwise stay with 43.
Step 3 — mix design: IS 10262 to the required grade; don't over-cement.
Step 4 — durability basics: cover, W/C and curing govern corrosion life regardless of cement grade — 43-grade doesn't change that.
Step 5 — accept per IS 456.
Result: adequate strength, calmer heat behaviour and economy — the over-reach of using 53-grade everywhere avoided by matching the cement to the actual requirement.
1. Defaulting to 53-grade instead. For ordinary M20–M35 work OPC 43 is adequate; reaching for 53 adds heat/shrinkage risk for unneeded strength.
2. Confusing cement grade with concrete grade. OPC 43 ≠ M43 concrete; the 43 is mortar strength feeding IS 10262 mix design.
3. Skimping curing because the cement 'is strong enough'. Durability is cover + W/C + curing, not cement grade.
4. Using 43-grade where durability/heat truly governs. Aggressive exposure / thick pours want PPC/slag/low-heat, not plain OPC.
5. Ignoring it as a deliberate choice. 43-grade is often the *right* engineering choice, not a lesser one — pick by requirement.
IS 8112 is current (2013) and OPC 43 is, for a large fraction of ordinary Indian RCC, the cement that should be the default — enough strength for routine work, with calmer heat and early-shrinkage behaviour than OPC 53. The persistent field error is treating cement grade as a strength contest and defaulting to 53 everywhere: more heat, more cracking risk, no benefit for concrete the structure doesn't need stronger. The sound logic is fitness for the governing requirement — 43-grade for general structural work, 53-grade only where early strength/high grade truly governs, PPC/slag/low-heat where durability or heat governs — and, regardless of grade, durability still comes from cover, W/C and curing. Choosing OPC 43 deliberately for ordinary work is good engineering, not a compromise.