Sieve Analysis and F.M. of Fine Aggregates

Aim:

This experiment aims to determine the particle size distribution of fine aggregates using sieve analysis and to calculate the Fineness Modulus (FM) of the aggregate.

Theory:

The particle size distribution of aggregates is an essential parameter in the design of concrete mixtures. It determines the amount of cement paste necessary to obtain certain workability and strength.

Sieve analysis is the most commonly used method to determine the particle size distribution of fine aggregates.

In this method, the aggregate sample is sieved through several sieves of different aperture sizes. The percentage of material retained on each sieve is determined and plotted on the curve.

Fineness Modulus (FM) is a measure of the average particle size of an aggregate. It is calculated by adding the cumulative percentages of material retained on each sieve and dividing by 100.

Apparatus and materials required:

We need the following apparatus and equipment for conducting the “Sieve analysis and FM of fine aggregates” test.

1. Sieve set consisting of a set of sieves of different mesh sizes (ranging from 4.75 mm to 75 microns)
2. A mechanical sieve shaker
3. Weighing balance (with an accuracy of 0.1 g)
4. Sample of fine aggregates
5. Tray to collect the sieved material
6. Sieve cleaning brush

Procedure:

1. Pick a representative sample of fine aggregate weighing around 500 grams.
2. Thoroughly clean all the sieves and arrange them in descending order of their mesh size.
3. Make sure to place the largest size at the top and the smallest size at the bottom.
4. Place the sample on the top sieve and start the mechanical sieve shaker for about 10-15 minutes.
5. After sieving it, weigh the material retained on each sieve and record the weight in a tabular format.
6. Calculate the percentage of all the material retained on each sieve and plot the graph of the particle size distribution.
7. Calculate the Fineness Modulus (FM) using the following formula.

 FM = (Cumulative Percentage retained / 100)

Precautions:

Before, during, and after performing the sieve analysis test, it is important to take precautionary measures and follow safety steps.

These are as follows:

1. Thoroughly clean all the sieves before and after each use to prevent any contamination.
2. The sample should be representative of an entire lot of aggregates to ensure accurate results.
3. Operate the mechanical sieve shaker for the recommended duration to ensure complete sieving.
4. The sieves and all the other apparatus should be handled carefully to avoid any damage.

Conclusion:

Sieve analysis and fineness modulus (FM) test are important and helpful in determining the particle size distribution of fine aggregates. Based on the results of this test, it can be concluded that the fine aggregate,

sample used in this test is suitable for the production of concrete with acceptable workability.

The particle distribution curve shows that the sample has a uniform distribution of particle sizes, with the dominant part of 150-600 microns. If the fineness modulus (FM) of the sample is 2.74, it indicates that it is medium fine.

It is important to note that the accuracy of the results obtained in this experiment depends on the representation of the sample and the accuracy of the equipment used. Therefore,

It is important to note that the accuracy of the results obtained in this experiment depends on the representation of the sample and the accuracy of the equipment used. Therefore,

To obtain accurate results, it is advisable to follow standard procedures and take proper precautions while performing the test.

In summary, sieve analysis and fineness modulus (FM) test are important in determining the particle size distribution and fineness of fine aggregates. This information is necessary to design concrete mixes with the desired workability and strength.