Learn the fineness of cement test as per IS 4031 (Part 1), including procedure, calculation, and IS code limits. This is an essential QA/QC test for MoRTH, NHAI, and highway construction projects.

1. Introduction

The fineness of cement test determines the particle size of cement, which directly influences the rate of hydration, strength development, and durability of concrete. In highway, bridge, and structural works, maintaining proper cement fineness is critical to achieve durable and high-performance concrete.

This test is conducted as per IS 4031 (Part 1): 1996 to assess the suitability of cement for use in laboratory and field conditions.

2. Definition – Fineness of Cement

Fineness of cement refers to the degree of grinding or particle size of cement. Finer cement provides a greater surface area for reaction with water, resulting in faster strength development.

Excessive fineness, however, may increase water demand and shrinkage. Therefore, control of cement fineness is essential to ensure both quality and workability of concrete.

3. Objective of Test

To determine the percentage of cement retained on a 90-micron IS sieve and to verify compliance with the requirements for cement used in highway and structural concrete works.

4. Apparatus Required

• 90-micron IS sieve
• Weighing balance (accuracy ± 0.01 g)
• Soft brush for cleaning
• Tray or pan

5. Test Procedure (Sieve Method)

1. Sample Preparation:
   Weigh 100 g of cement accurately and record it as W₁.
2. Sieving:
   Place the cement on a 90 µm IS sieve and sieve continuously for 15 minutes using circular and vertical motions.
3. Residue Collection:
   Collect the cement retained on the sieve and weigh it as W₂.
4. Calculation:
   Fineness (%) = (W₂ / W₁) × 100
5. Repetition:
   Conduct the test three times and report the average value.

6. Acceptance Criteria (As per IS Codes)

7. Alternative Method – Blaine’s Air Permeability Test

The Blaine’s Air Permeability Test determines the specific surface area of cement (m²/kg) by measuring air flow through a compacted cement bed.

Minimum requirement as per IS 4031:
OPC 33 / 43 / 53 Grade → ≥ 225 m²/kg

This method is generally adopted in central laboratories and NHAI QA/QC setups for more precise control of cement quality.

8. Importance of Fineness Test

• Ensures uniform hydration and strength development
• Controls setting time and workability
• Reduces the risk of cracking due to uneven hydration
• Maintains quality compliance in MoRTH and NHAI projects

9. Precautions

• Protect the cement sample from moisture before testing
• Clean the sieve thoroughly after each test
• Avoid excessive vibration during sieving
• Conduct the test at standard laboratory temperature

10. Result & Interpretation

Fineness (%) = (Residue weight W₂ / Sample weight W₁) × 100

If the residue exceeds the specified limit, the cement fails the fineness requirement as per IS specifications.

11. Conclusion

The fineness of cement test as per IS 4031 (Part 1) is a vital quality control test in highway and structural construction. Regular monitoring ensures optimal cement performance, compliance with MoRTH and NHAI standards, and long-term durability of concrete structures.

12. Frequently Asked Questions (FAQ)

Q1. What is the permissible limit for fineness of cement?
Not more than 10% residue on a 90 µm sieve for OPC.

Q2. Which IS code specifies the fineness test?
IS 4031 (Part 1): 1996.

Q3. Why is fineness important?
It affects hydration rate, setting time, and strength development.

Q4. What is the alternative method?
Blaine’s Air Permeability Method.