The Fineness test of cement is done by sieving cement sample through standard IS sieve. The weight cement particle whose size greater than 90 microns is determined and the percentage of retained cement particle are calculated. This is known as Fineness of cement.
Why Cement Fineness test required?
We know that cement hydrates when cement is mixed with the water and a thin layer are formed around the particle. This thin layer grows bigger and makes cement particles to separate. Because of this, the cement hydration process slows down. On other hands, cement smaller particle react much quicker than the larger particle. A cement particle with diameter 1µm will react entirely in 1 day, whereas the particle with diameter 10µm takes about 1 month.
But, there is a side effect of having too much of smaller particles in cement results in quick setting, leaving no time for mixing, handling and placing. Therefore to increase the setting time of cement, cement is must be manufactured in a different range of particle sizes.
To determine the fineness of cement by using 90 µm IS sieve as per IS: 4031 (Part 1) – 1996.
- 90µm IS Sieve,
- Weight Balance having capacity 10 mg to 100 g,
- Nylon or pure bristle brush
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- Collect a sample of cement and rub with your hands. The Fineness test sample should be free of lumps.
- Take 100 gm of cement sample and note its weight as W1.
- Drop 100 gm of cement in 90 µm sieve and close it with the lid.
- Now, shake the sieve with your hands by agitating the sieve in planetary and linear movements for 15 minutes.
- After that take weight the retained cement on the 90 µm sieve as W2.
Fineness = (W2/W1) * 100
- Then after, calculate the percentage of Weight of cement-retained on Sieve.
- Repeat this procedure with three different samples of cement and average the values for accurate results.
|Sr.No.||Weight of Cement |
|Weight Cement Sample |
Retained on 90µm Sieve
|Fineness of Cement|
|1||100 gm||4.65||4.65 %|
|2||100 gm||8.25||8.25 %|
|3||100 gm||7.95||7.95 %|
Result: The standard cement should have fineness less than 10 % as per IS Recommendations.