Sulphate Resistant Cement (SRC)
Sulphate Resistant Cement (SRC)
🧱 Sulphate Resistant Cement (SRC) — Full Definition
Sulphate Resistant Cement (SRC) is a special type of Portland cement designed to resist the destructive effects of sulphate attack from soil, groundwater, or seawater. It is mainly used in environments where concrete is exposed to high sulphate concentrations.
SRC achieves its resistance by minimizing the amount of Tricalcium Aluminate (C₃A) in its composition (typically less than 5%), since this compound reacts adversely with sulphates.
🔹 Main Components
| Component | Typical Percentage | Function |
|---|---|---|
| Clinker (low in C₃A) | 94–96% | Provides strength while resisting sulphates |
| Gypsum | 3–5% | Controls setting time |
🔹 Chemical Composition (Approx.)
| Compound | Symbol | Typical Range (%) |
|---|---|---|
| Tricalcium Silicate | C₃S | 45–60 |
| Dicalcium Silicate | C₂S | 20–30 |
| Tricalcium Aluminate | C₃A | ≤ 5 |
| Tetracalcium Aluminoferrite | C₄AF | 15–20 |
🔹 Physical Properties
| Property | Typical Value |
|---|---|
| Specific Gravity | 3.10 – 3.15 |
| Fineness (Blaine) | 300–350 m²/kg |
| Initial Setting Time | ≥ 45 minutes |
| Final Setting Time | ≤ 600 minutes |
| Compressive Strength (28 days) | 42.5–52.5 MPa depending on grade |
🔹 Available Grades
SRC 42.5 N/R – standard sulphate-resistant cement.
SRC 52.5 N/R – high-strength and severe sulphate resistance.
🔹 Applications
Marine and coastal structures (ports, jetties, seawalls).
Foundations in sulphate-rich soils.
Sewage and wastewater treatment plants.
Concrete pipes and underground structures.
Bridges, tunnels, and irrigation canals exposed to sulphate water.
🔹 Advantages
Excellent resistance to sulphate and chloride attack.
Reduced risk of cracking and expansion.
Suitable for hot and humid climates.
Long-term durability in aggressive environments.
🔹 Packaging for Export
| Form | Common Sizes |
|---|---|
| Bags | 50 kg (multi-layer kraft paper) |
| Bulk | 1–1.5 MT jumbo bags or bulk vessel shipment |
🔹 Storage Recommendations
Store in a dry, moisture-free environment on wooden pallets, covered with waterproof material. Avoid direct contact with the ground or humidity to preserve quality and strength.
