What Is Fineness Modulus of Sand?
The fineness modulus of sand is a measure of the average particle size of sand particles. It is calculated by adding the cumulative percentages of sand particles retained on each of a specified series of sieves and dividing the sum by 100. The fineness modulus of sand ranges from 2.2 to 3.2.
In other words, the fineness modulus of sand is a value that indicates the coarseness or fineness of sand particles.
It is commonly used in the construction industry to determine the amount of sand to be used in concrete mixtures, as well as to ensure consistency and quality of the sand used in construction projects.
A lower fineness modulus indicates a finer sand particle size, while a higher fineness modulus indicates a coarser sand particle size.
To find the fineness modulus of fine aggregate required IS sieve are sizes of 4.75mm, 2.36mm, 1.18mm, 0.6mm, 0.3mm, and 0.15mm.
Read More: Sand Moisture Content Test – Procedure and Result
Fineness Modulus of Sand Test
IS Code for Fineness Modulus of fine aggregate: IS: 383 -1970
- Sieves as per IS standards
- Mechanical sieve shaker(optional)
- Dry oven
- Digital weight scale
Sample preparation for fineness modulus of sand is given as under
Take a sample of sand in a pan and placed it in the oven at a temperature of approximately 100-110°C.
After drying, take the sample out of the oven and note down its weight using a digital weighing scale.
Sieve Analysis of Fine Aggregate
Following is the test procedure for the fineness modulus of the sand test,
1) Take the sieves and arrange them in descending order with the largest sieve on top.
2) If a mechanical shaker is used for shaking, then put the sieve set in position on the mechanical shaker and pour the sample in the top sieve & then close it with the sieve plate.
3) Then switch on the machine and shaking of sieves should be done at least for 5 minutes.
4) If the shaking is done manually (by the hands) then pour the sample in a top sieve and close it then hold the top two sieves and shake it inwards and outwards, vertically and horizontally.
5) After some time shake 3 and 4 and finally last sieves simultaneously.
6) After sieving, record the sample weights retained on each sieve. Then find the cumulative weight retained.
7) Finally, determine the cumulative percentage retained on each sieve.
8) Add all cumulative percentage values and divide by 100 then we will get the value of fineness modulus.
Calculation of F.M. of Sand
Let us assume the dry weight of the sample = 1000gm
After sieve analysis, the values that appeared are tabulated below.
|Sieve size||Weight retained(g)||Cumulative weight retained (g)||Cumulative percentage |
Hence, Fineness modulus of Sand = (Cumulative % retained) / 100
= (275 / 100)
Range of Fineness of Modulus
The following table indicates sand fineness modulus value ranges from 2.6 to 3.2.
|Types of Sand||Fineness Modulus (F. M) Value|
|Fine Sand||2.6 – 2.6|
|Medium Sand||2.6 -2.9|
|Coarse Sand||2.9 -3.2|
Fineness modulus with respect to various zones of sand according to IS 383-1970 are given in the table below.
Free Download Sieve Analysis Excel Sheet
What is the fineness modulus used for?
Use of Fineness Modulus
The fineness modulus specifies the average size of the sand and aggregate particles for the mixing of concrete. However, the size will be beneficial in understanding how easily the concrete pours and spreads, along with its strength and durability once cured.
Which zone sand is the finest sand?
Sands belonging to Zone-IV are the finest of a type. And on the contrary to that Zone-I has Coarse Sand. As a result, Zone-IV has the lowest Fineness Modulus Value.
What is the FM of sand?
The Fineness Modulus of Sand is an index number that indicates the mean size of the sand particles. It is calculated by performing the sieve analysis test with standard IS sieves. The fineness modulus of sand ranges from 2.2 to 3.2.
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