What is the main advantage of Rapid Hardening Portland Cement (RHPC)?

High early strength development. Its 1-day strength is approximately equal to the 3-day strength of OPC, and its 3-day strength is similar to the 7-day strength of OPC.

What is the minimum compressive strength for RHPC at 1 day and 3 days?

Minimum 16 MPa at 1 day and 27.5 MPa at 3 days, as per Table 2.

Are the setting times for RHPC different from OPC?

No, the requirements are the same: minimum initial setting time is 30 minutes and maximum final setting time is 600 minutes (Table 2).

Can RHPC be used for mass concrete foundations?

It is generally not recommended due to its high heat of hydration, which can lead to thermal stress and cracking in large volume pours. Low Heat Cement (IS 12600) is preferred for such applications.

IS 8041

: 1990

Rapid Hardening Portland Cement - Specification

CurrentSpecializedSpecificationMaterials Science · Cement

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This standard specifies the manufacturing and chemical/physical requirements for Rapid Hardening Portland Cement (RHPC). RHPC is characterized by its high rate of strength gain, achieving higher early strength compared to Ordinary Portland Cement (OPC), making it suitable for applications requiring rapid construction or early formwork removal.

Specifies requirements for rapid hardening portland cement for applications requiring early strength development.

Quick Reference Values

Minimum 1-day compressive strength16 MPa

Minimum 3-day compressive strength27.5 MPa

Minimum fineness (Blaine's)325 m²/kg

Minimum initial setting time30 minutes

Maximum final setting time600 minutes

Maximum loss on ignition5.0 %

Maximum total sulfur content (as SO3)3.0 %

Practical Notes

Due to its higher fineness and C3S content, RHPC generates more heat of hydration than OPC. This makes it beneficial for cold weather concreting but requires caution in mass concrete pours to avoid thermal cracking.

The primary use is to accelerate construction schedules by allowing for earlier stripping of formwork and faster precast element production.

Despite rapid strength gain, its ultimate strength is comparable to that of OPC of a similar grade.