[FDArchitects]

Rapid Hardening Portland cement (RHPC) is a special purpose cement used in concrete to ensure a higher rate of early age strength development than that typically achieved using Normal Portland cement (NPC).

The improved early age strength performance of RHPC is principally achieved through increased product fineness.

As par Indian Standard code IS 8041 : 1990 
The setting time of the by the Vicat apparatus IS 4031 (Part 5) : 1988 following requirements:
a) Initial setting time : than 30, and cement, when tested method described in shall conform to the in minutes, not less
b) Final setting time in minutes, not more than 600.

MANUFACTURE REQUIREMENT OF RHPC
Rapid hardening Potland cement shall be manufactured by intimately mixing together calcareous and argillaceous and/or other silica, alumina or iron oxide bearing materials,
burning them at a clinkering temperature and grinding the resultant clinker so as to produce a cement capable of complying with this specification.

[Mili Jain]

please explain the properties of RHPC

[Manish Jain]

Rapid Hardening Portland cement
Properties

Similar chemical composition as OPC but different proportion
Causes to the increased rate of early hardening
Concrete made with RHPC develops in 7 days the same strengths
High early strength is achieved by increasing the CS & CA content


More finely grounded than OPC
Allows formwork to be struck earlier
Providing savings either the quantity of formwork required in time
Produce heat earlier than OPC, so it can be used in cold weather
Qualities

RHPC is produced using carefully selected raw materials.
Strict quality control throughout each stage of the manufacturing process ensures that a consistent final product is achieved.
Strength

Rapid Hardening Portland cement achieves higher earlier strengths than OPC because it is more finely ground.
Rapid Hardening Portland cement is chemically similar to OPC and as such concrete mixes should be designed with this in mind.
In particular, optimum ultimate strength of concrete using RHPC will depend, like OPC, on careful attention to the water/cement ratio, consistent with ensuring satisfactory placing and compaction.