Pick - out the application where the use of rapid hardening cement is recommended.

Question

Question

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PGCIL DT Civil 13 Aug 2021 Official Paper (NR I)

Concrete used for fabrication of pipes which are likely to be buried in marshy region
Where formwork is required to be removed early for re-use elsewhere
In the construction of sewage treatment works
Concrete to be used in marine condition

Answer 1

Explanation

Rapid Hardening Cement

The initial and final setting times of this cement are the same as those of ordinary cement, But it attains high strength in the early days.
It contains a high percentage of tricalcium silicate to the extent of about 56%.

This is due to the following facts.

It offers the following advantages:

As it sets rapidly, the construction work may be carried out speedily.
The formwork of concrete can be removed earlier and it can therefore be used frequently.
It obtains strength in a short period. The compressive strength at the end of one day is about 11.50 N/mm2 and that at the end of 3 days is about 21 N/mm2. Similarly, the tensile strength at the end of one day is about 2 N/mm2 and that at the end of 3 days is about 3 N/mm2.
It is light in weight.
It is not damaged easily.
The structural members constructed with this cement may be loaded earlier.
This cement requires short period of curing.
The use of this cement allows higher permissible stresses in the design. It, therefore, results in economic design.