PARTICLE SIZE DISTRIBUTION

(IS: 2386, PART-1 -1963)

OBJECT: To find fineness modulus of coarse and fine aggregate

Instruments: Sieves, Fine aggregate, coarse aggregate, and Weighing Machine.

 

THEORY:

This strategy decides the fineness modulus of solid fine total utilized in the assessment of normal and manual sands for Portland cement concrete. The standard meaning of fineness modulus is as per the following: An empirical factor obtained by adding the total percentages of a sample of the aggregate retained on each of a specified series of sieves and dividing the sum by 100. all in all a little worth showed a fine aggregate while a huge worth demonstrates a coarse aggregate. The limit for fine totals usually goes from 2.00 to 4.00 and for a coarse total from 6.50 to 8.00.

PROCEDURE:

Coarse aggregate:

1.          From the quartering, we take random 5kg aggregate size 20 mm

2.        Carry out sieving by hand, shake each sieve in order 75mm ,40mm, 20mm, 10mm, and No's 480, 240, 120, 60, 30, & 15 over a clean dry tray for a period not less than 2 min.

3.        The shaking is finished with a fluctuated movement in reverse and forward, left to right, round, clockwise, and anticlockwise and with continuous jostling. 

4.         so the material is continued moving over the sifter surface is regularly evolving ways. 

5.         Discover the weight held on each strainer taken all together.

Fine aggregate:

1.         From the quartering, we take a random 1kg fine aggregate 

2.         Arrange the sieves in order of No. 480, 240, 120, 60, 30 and 15 keeping sieve 480 at top and 15 at the bottom.

3.        Fix them in the strainer shaking machine with the container at the base and spread at the top. 

4.    Keep the sand in the top strainer no 480, do the sieving in the arrangement of sieves, and organized before for at the very least 10 minutes. 

5.       Discover the weight held in each strainer..

6.      Plot a chart of percent passing by weight versus strainer size, with the cutoff points determined in CSA standard A23.1 for fine and coarse total sizes superimposed.

 Coarse aggregate:      Wt. of coarse aggregate taken:                      Kgs.

S. No	Sieve size (mm)	Weight retained	% Weight retained	% weight passing	Cumulative %Weights retained
1	75
2	40
3	20
4	10
5	4.75
6	2.36

 

Fine aggregate:          Wt. of fine aggregate is taken:               Kgs

S. No	Sieve size	Weight retained	% Weight retained	% weight passing	Cumulative % Weights retained
1	4.75 mm
2	2.36 mm
3	1.18 mm
4	600 micron
5	425 micron
6	300 micron
7	150 micron
8	75 micron
9	Pan

 

CALCULATION-

·         Calculate the Fineness Modulus (FM) as the sum of the percents retained on the series of sieves divided by 100:

FM =        (∑Cumulative percent retained) / 100

 

Safeguards 

1. The Sample ought to be in air-dry condition, if not, might be dried at room temperature or by warming at a temperature of 1000-1100 C. 

2. Sieves ought to be dry and clean before use. 

3. Each sieve ought to be shaken for a period at the very least 2 min. 

4. Try not to compel the material through Sieves by hand pressure.

RESULT:

The fineness modulus of given fine aggregate:         

 The fineness modulus of given coarse aggregate:

  COMMENTS: Limits of fineness modulus of aggregates.

Maximum size of aggregate	Minimum retained	Maximum retained
Fine aggregate	2	3.5
Coarse aggregate	2	3.5
20 mm	6	6.9
40 mm	6.9	7.5
75 mm	7.5	8.0
150 mm	8.0	8.5

 

 

 

 

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