1.1 FINENESS
AIM
To determine the fineness of cement by dry sieving as per
IS: 4031 (Part 1) - 1996.
PRINCIPLE
The fineness of cement is measured by sieving it through a
standard sieve. The proportion of cement, the grain sizes of
which, is larger than the specified mesh size is thus determined.
APPARATUS
i) 90µm IS Sieve
ii) Balance capable of weighing 10 g to the nearest 10 mg
iii) A nylon or pure bristle brush, preferably with 25 to 40 mm
bristle, for cleaning the sieve
PROCEDURE
i) Weigh approximately 10 g of cement to the nearest 0.01 g and
place it on the sieve.
ii) Agitate the sieve by swirling(घूर्णन), planetary(ग्रहिये) and linear(रेखीये)
movements, until no more fine material passes through it.
iii) Weigh the residue and express its mass as a percentage R1,
of the quantity first placed on the sieve to the nearest 0.1
percent.
iv) Gently brush all the fine material off the base of the sieve.
v) Repeat the whole procedure using a fresh 10g sample to
obtain R
2. Then calculate R as the mean of R1 and R2 as a
percentage, expressed to the nearest 0.1 percent. When the
results differ by more than 1 percent absolute, carry out a
third sieving and calculate the mean of the three values.
REPORTING OF RESULTS
Report the value of R, to the nearest 0.1 percent, as the residue
on the 90µm sieve.