Overview
Fineness of cement is measured by sieving it on standard sieve. The proportion of cement of which the grain sizes are larger than the specified mesh size is thus determined.
Apparatus
Measuring Instruments
NAME | CAPACITY / RANGE / SIZE | ACCURACY / LEAST COUNT |
Sieve | 90 micron mesh | — |
Balance | 10g (max.) | 10 mg |
Supplementary accessories
Glass rod, stoppered jar, pan, lid |
Procedure
- Agitate the sample of cement to be tested by shaking for 2 minutes in a stoppered jar to disperse agglomerates. Stir the resulting powder gently using a clean dry rod in order to distribute the fines throughout the cement.
- Attach a pan under the sieve to collect the cement passing the sieve.
- Weigh approximately 10 g of cement to the nearest 0.01 g and place it on the sieve. Fit the lid over the sieve.
- Agitate the sieve by swirling, planetary and linear movement until no more fine material passes through it.
- Remove and weigh the residue. Express its mass as a percentage (R1) of the quantity first placed in the sieve.
- Repeat the steps 3 to 5 with a fresh sample to obtain R2.
- Note :: If R1 & R2 differ by more than 1%, then carryout a third sieving and calculate R3.
Calculation
Calculate the residue of cement R as the mean of R1 & R2 (or R1, R2 & R3) in %, expressed to the nearest 0.1%.
Procedure To Check Sieve
- Follow the steps (1 to 6) as mentioned earlier with a reference cement sample or certified reference material (i.e. CRM).
- Calculate two values ‘P1’ & ‘P2’ and calculate mean ‘P’ of ‘P1’ & ‘P2’.
- From the certificate of reference cement sample find out the known value of residue on 90 micron mesh sieve.
- Calculate a correction factor as per the below mentioned formula.
Where
R0=Known value of residue as per reference material certificate.
P=Mean value of P1 & P2.
(The value of F may be 1.00±0.20)
5. Multiply this correction factor ‘F’ with mean value of ‘R’
Precaution
- Before sieving, air set lumps of cement should be broken
- Sieving should be done by rotating the sieve and not by translation.
Technical Discussions
- Fineness of cement has a great effect on the rate of hydration and hence the rate of gain of strength.
- Fineness of cement increases the rate of evolution of heat.
- Finer cement offers a great surface area for hydration and hence faster the development of strength.
- Increase in fineness of cement also increases the drying shrinkage of concrete and hence creates cracks in structures.
- Excessive fineness requirement increases cost of grinding.
- Excessive fine cement requires more water for hydration, resulting reduced strength and durability.
- Fineness of cement affects properties like gypsum requirement, workability of fresh concrete & long term behavior of structure.
- Coarse cement particles settle down in concrete which causes bleeding.
Test Standard Reference
- IS:4031(Part 1):1996-Method of physical test for cement(Determination of fineness by dry sieving)
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Where mention the fineness
WHAT IS THE LIMITS OF CEMENT FINENESS IN PERCENTAGE?
Would I know weight variations permissible physical lab
What is the inference of fineness of cement.
sir what is conclusions on this methode
Dear sir Dry sieving method ( FINENESS OF CEMENT BY DRY SIEVING (IS:4031-PART 1-1996) ) What is the Specification Fineness test value ?
plz mention As per IS:Code…
Dear Sir,
As per IS which sieve use in cement before chemical analysis
Regards
S P Tiwari
Dear Sir,
As per IS which sieve use in cement sieving for chemical analysis
Regards
S P Tiwari
Dear sir
We have studied that while doing the fineness of cement not more than 10% cement retained on the 90 micron sieve , but when i studied Is 4031 part -1 , i did not see in code these words. so sir please justify me is it is right or wrong ? if right then give me the attachment of code.
With Regards
Vivek Bharti
Thanks for sharing this guide on using a cement fineness test. It’s good to know that the actual procedure isn’t very difficult, and that I should mostly prepare myself for stirring contents in a pan. You mentioned that it would be a good idea to calculate R3 if you find that your first two calculations were too different. What should you do if your R3 value is also very different from your R1 and R2 values? Should you start the process over from the beginning?