Reviewed by Er. Inderjit Sharma (Retd.), Punjab PWD
What is fineness of cement? It tells you how finely the cement has been ground. In this test we sieve cement through a very fine 90 micron sieve and weigh what stays on it (the coarse part).
Why it matters: finer cement has more surface area for water to react with, so it gains strength faster and gives better workability. Coarse cement reacts slowly, gives lower early strength, and may bleed more.
This guide follows IS 4031 (Part 1).
Why Fineness Matters
Apparatus Required
90 micron IS sieve
Very fine brass or stainless mesh, with a pan below and a lid on top.
Balance (0.01 g)
500 g capacity; weighs the 10 g sample and residue.
Brush
Soft nylon or bristle brush to clean the underside of the mesh.
Stoppered jar & rod
Shaking the cement in a jar breaks up small lumps before sieving.
Procedure
- Take a representative sample from the lot and weigh 10 g of cement to the nearest 0.01 g: R1.
- Put it in a stoppered jar and shake for 2 minutes to break up lumps. Wait 2 minutes, then stir gently with a clean, dry rod to spread the fines.
- Pour the cement onto the 90 micron sieve fitted with its pan, and put the lid on.
- Sieve by hand with swirling, circular and side-to-side movements until no more fine material passes through.
- Gently brush the underside of the sieve into the pan so that fine dust clinging to the mesh is not counted as residue.
- Weigh the residue left on the sieve: R2.
- Do two tests. If the two results differ by more than 1% (absolute), do a third and average all three.
Calculation
R1 = weight of cement taken (10 g); R2 = weight retained on the 90 micron sieve. Report each result and the mean to the nearest 0.1%. Lower residue = finer cement.
📝 Worked example
R1 = 10.00 g, R2 = 0.62 g → residue = 0.62 ÷ 10 × 100 = 6.2% ✓ (within 10%)
📏 Limit
A residue of not more than 10% is the commonly used limit for this test.
Try It: Fineness Calculator
Enter your weights in grams. The values filled in are a worked example.
Precautions
🤲 Don’t spill
Sieve gently with the lid on; any cement lost from the sieve makes the residue look smaller.
🧹 Brush the underside
Brush fine dust off the bottom of the mesh into the pan, but never push residue through the sieve.
🔍 Check the sieve
Use a clean, undamaged sieve. A torn or stretched mesh gives a falsely fine result; replace it.
😷 Dust safety
Cement dust irritates eyes and lungs. Wear a dust mask and goggles while sieving.
Practical Tips for Site Engineers
1. Quick Field Checks on Cement
📅 Date of packing
Check the week/month printed on the bag. Cement loses strength with age; use it within about 3 months, or test it again if older.
✊ Lump test
Lumps that crumble easily between fingers are fine. Hard lumps that don’t break mean the cement has started to set; reject that cement.
🤏 Feel test
Good cement feels smooth and cool when rubbed between fingers. A gritty feel suggests adulteration or coarse grinding.
🎨 Colour
Uniform greenish-grey colour. Patches of different colour can mean contamination or mixing of different cements.
2. Store Cement Properly
- Keep it dry: store bags in a closed, waterproof shed on a raised platform (wooden planks or plastic sheet), at least 150–200 mm above the floor and away from walls.
- Stack properly: stack bags close together to reduce air circulation, and don’t stack more than about 10 bags high to avoid lumps from pressure.
- First in, first out: use older stock first. Mark the arrival date on each stack.
- Keep brands and types separate: don’t mix OPC, PPC and PSC stacks, or different brands.
- Test doubtful cement: if bags are old, have hard lumps, or were exposed to rain, test for fineness, setting time and strength before use.
Key Takeaways
- Fineness shows how finely cement is ground; finer cement reacts faster and gains early strength.
- Sieve 10 g (R1) on the 90 micron sieve after shaking to break lumps; weigh the residue (R2).
- Fineness (residue %) = R2 ÷ R1 × 100; lower is finer; commonly limited to 10%.
- Two tests; if they differ by more than 1%, do a third.
- On site: check the packing date, lumps, feel and colour; store bags dry, raised, max 10 high, first in first out.
References: IS 4031 (Part 1): Methods of Physical Tests for Hydraulic Cement – Determination of Fineness by Dry Sieving; IS 4031 (Part 2): Fineness by Blaine Air Permeability Method; IS 269: Ordinary Portland Cement – Specification; IS 4082: Stacking and Storage of Construction Materials at Site.