What is the key chemical requirement that makes this cement sulphate-resistant?

The Tricalcium Aluminate (C3A) content is limited to a maximum of 5 percent by mass (Table 1).

Can SRPC be used for general purpose construction?

While technically possible, it is not economical. SRPC is more expensive and has slower early strength gain than OPC, so its use should be limited to environments where sulphate resistance is specifically required.

What is the minimum 28-day compressive strength requirement for SRPC?

The minimum average compressive strength of three mortar cubes is 33 MPa at 28 days (Table 2).

Is this cement suitable for structures exposed to both sulphates and chlorides?

No, this standard is for resistance to sulphates only. For combined chloride and sulphate environments, Portland Slag Cement (IS 455) or Pozzolana Cements (IS 1489) with low C3A clinker are preferred as per IS 456.

IS 12330

: 1988

Sulphate Resisting Portland Cement - Specification

CurrentSpecializedSpecificationBIMMaterials Science · Cement

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This standard lays down the manufacturing and testing specifications for Sulphate Resisting Portland Cement (SRPC). It defines the chemical composition and physical properties required for cement intended for concrete structures subjected to sulphate attack, such as those in marine environments, foundations in aggressive soils, or wastewater facilities.

Specifies requirements for sulphate resisting portland cement suitable for use in structures exposed to sulphate attack.

Quick Reference Values

Tricalcium Aluminate (C3A) ContentMax 5.0 %

2C3A + C4AF ContentMax 25.0 %

Magnesia (MgO) ContentMax 6.0 %

Total Sulphur Content (as SO3)Max 2.5 %

Initial Setting TimeMin 30 minutes

Final Setting TimeMax 600 minutes

Compressive Strength (28 days)Min 33 MPa

Soundness by Le ChatelierMax 10 mm

Practical Notes

SRPC generally exhibits slower strength gain compared to Ordinary Portland Cement (OPC), especially at early ages (3 and 7 days). This must be accounted for in project timelines and formwork stripping schedules.

Due to its low C3A content, SRPC has a lower heat of hydration, which is beneficial for mass concrete pours to control thermal cracking.

Using SRPC does not eliminate the need for dense, impermeable, and well-cured concrete. Proper mix design and workmanship are still crucial for overall durability.