When a 33 grade Ordinary Portland cement is tested for its physical requirements, then it must satisfy the following specifications given by IS 269.
- The fineness value of 33 grade OPC when tested by Blaine’s air permeability method shall not be less than 225 m2/kg.
- The expansion value (i.e. soundness) of unaerated cement when tested by Le-Chaelier method shall not be more than 10 mm and when tested by autoclave method shall not be more than 0.8%.
- Initial setting time of 33 grade OPC shall not be less than 30 minutes.
- Final setting time of 33 grade OPC shall not be more than 600 minutes.
- The average compressive strength of at least 3 mortar cubes, when tested as per IS-4031-Part 6, shall be as follows.
||Compressive strength (MPa)
||72 ± 1 hour
||Not less than 16 Mpa
||168 ± 2 hour
||Not less than 22 Mpa
||672 ± 4 hour
||Not less than 33 Mpa