Fineness Test of Cement as per Indian Standard (IS 4031: Part 1)

 Fineness Test of Cement as per Indian Standard (IS 4031: Part 1)

Aim
The aim of this test is to determine the fineness of cement using the dry sieving method. Fineness of cement affects the rate of hydration, setting time, and strength development of the concrete. Finer cement has a greater surface area and therefore hydrates more rapidly, which leads to early strength development.

Apparatus

1. IS Sieve (90 µm sieve)
2. Weighing balance (accurate to 0.1 g)
3. Brush
4. Tray
5. Sample of cement (100g)

Theory
The fineness of cement is measured as the percentage of cement particles passing through a 90-micron sieve (IS 4031: Part 1). The rate of hydration and strength development of cement are affected by the particle size distribution. Finer particles react faster and develop strength more rapidly, whereas coarser particles contribute to long-term strength. Excessive fineness can result in undesirable properties like shrinkage and increased heat of hydration. A standard sieve of 90 µm is used for this test, and the weight of cement retained on the sieve is used to determine the fineness.

Procedure

1. Weigh approximately 100g of cement sample using a weighing balance.
2. Place the cement sample in the sieve and close it with the lid.
3. Shake the sieve for about 15 minutes, either manually or using a mechanical sieve shaker.
4. After sieving, weigh the residue (cement particles retained on the sieve).
5. Record the weight of the residue.

Observation Table

Sample No.	Weight of Cement (W1)	Weight of Residue (W2)	% of Cement Retained (W2/W1 * 100)
1	100g	5g	5%
2	100g	4.5g	4.5%
3	100g	4g	4%

Sample Readings

For instance, if 100g of cement is taken and 5g of cement is retained on the sieve, the percentage retained is:

$$\frac{5g}{100g} \times 100 = 5\%$$

Similarly, the calculation is performed for each sample.

Reporting the Results

• The fineness of cement is reported as the percentage of the weight of cement retained on the 90 µm IS sieve.
• The acceptable limit of fineness for cement is generally not more than 10% retained on the sieve.
• The results should be averaged from three different samples to ensure accuracy.

Conclusion
The fineness of cement affects its performance in concrete, especially in terms of early strength development and the rate of hydration. Based on the test results, if the cement shows a high percentage of particles retained on the sieve, it indicates that the cement is coarser, which may affect its performance. Fineness is an important factor to monitor, as finer cement hydrates faster and contributes to the early strength of concrete.