Fineness Test:
It is carried out to check proper grinding of cement. The fineness of cement particles may be determined either by sieve test or by permeability apparatus test.
In sieve test, 100 gm of the cement is taken and it is continuously passed for 15 minutes through standard BIS sieve No. 9 (90 micron). The residue is then weighed and this weight should not be more than 10% of original weight for OPC.
In permeability apparatus test, specific surface area of cement particles is calculated. This test is better than sieve test and it gives an idea of uniformity of fineness. The exact surface acts as a measure of the frequency of particles of average size. The specific surface of cement should not be less than 2250 cm2/gm.