The Fineness test of cement is done by sieving a cement sample through a 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 the Fineness of cement.
Significance of Fineness of Cement
- The fineness of cement has an important bearing on the rate of hydration and hence on the rate of gain of strength and also on the rate of evolution of heat.
- Finer cement offers a greater surface area for hydration and hence faster the development of strength.
- The fineness of grinding has increased over the years. But now it has got nearly stabilized. Different cements are ground to different fineness.
- Increase in fineness of cement is also found to increase the drying shrinkage of concrete.
PROCEDURE OF FINENESS TEST OF CEMENT:
- 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
- Drop 100 gm of cement in 90 µm sieve and close it with the lid.
- Now, shake the sieve 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
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.
Fineness Test of Cement & Result:
Sr.No13. | Weight of Cement Sample (W1) | Weight Cement Sample Retained on 90µm Sieve (W2) | Fineness of Cement |
1 | 100 gm | 3.65 | 3.65 % |
2 | 100 gm | 5.25 | 5.25 % |
3 | 100 gm | 8.75 | 8.75 % |
Average | 5.88 % |
Result: The standard cement should have fineness less than 10 % as per IS Recommendations.