🧪 Cement Fineness Test (Dry Sieving Method) | Aim, Principle & Apparatus
Cement fineness test is performed to determine the particle size of cement using a standard 90 μm sieve. Fineness of cement influences the rate of hydration, strength development, and overall quality of concrete. This test ensures that cement meets the required standards for construction.
🎯 Aim
To determine the fineness of cement by dry sieving.
📐 Principle
The fineness of cement is measured by sieving it through a standard sieve. The proportion of cement, the grain size of which is larger than the specified mesh size, is thus determined. Finer cement particles have larger surface area, leading to faster hydration and higher early strength.
🛠️ Apparatus
- 90 μm sieve (IS sieve No. 9)
- Balance capable of weighing 10 g to the nearest 10 mg (0.01 g)
- A nylon or pure bristle brush (25–40 mm bristle) for cleaning the sieve
📋 Procedure (Dry Sieving Method)
- Weigh approximately 10 g of cement to the nearest 0.01 g and place it on the 90 μm sieve.
- Agitate the sieve by swirling, planetary and linear movements, until no more fine material passes through it.
- Weigh the residue and express its mass as a percentage R₁ of the quantity first placed on the sieve (to the nearest 0.1 %).
- Gently brush all the fine material off the base of the sieve.
- Repeat the whole procedure using a fresh 10 g sample to obtain R₂. Calculate R as the mean of R₁ and R₂ as a percentage, expressed to the nearest 0.1 %.
- If the results differ by more than 1 % 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 %) as the residue on the 90 μm sieve. This value indicates the fineness of the tested cement sample. Lower residue indicates finer cement, which generally provides better strength and durability.
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