Cement Types & Chemical Composition

Detailed oxide chemistry, blend composition, and performance comparison across OPC, PSC, PPC, and GGBS.

Ordinary Portland Cement (OPC)

IS 269:2015 · Made by grinding clinker + gypsum · ~1450°C kiln

Highest CO₂

Blend composition

Clinker 95–96%

G 4%

G = Gypsum (controls setting time). No supplementary cementitious materials.

Oxide chemistry of OPC clinker

CaO (lime)

60–67%

SiO₂ (silica)

19–23%

Al₂O₃ (alumina)

3–5%

Fe₂O₃ (iron oxide)

2.5–4.5%

MgO (magnesia)

0.5–2%

SO₃ (sulfate)

1.5–3%

Key clinker mineralogy (Bogue phases)

C₃S – Alite (tricalcium silicate)45–65% – early strength

C₂S – Belite (dicalcium silicate)10–25% – long-term strength

C₃A – Tricalcium aluminate6–12% – fast set, heat

C₄AF – Ferrite phase8–12% – colour, moderate heat

CO₂ emission intensity~820–850 kg/tonne clinker

Heat of hydrationHigh (450–600 J/g)

Early strength (3d)23–33 MPa

28d compressive strength43–53 MPa (grade dependent)

Sulphate/chloride resistanceLow