2. TESTS ON AGGREGATES

2.1 SIEVE ANALYSIS

AIM

To determine the particle size distribution of fine and coarse

aggregates by sieving as per IS: 2386 (Part I) - 1963.

PRINCIPLE

By passing the sample downward through a series of standard

sieves, each of decreasing size openings, the aggregates are

separated into several groups, each of which contains aggregates

in a particular size range.

APPARATUS

FIG. 4 : A SET OF IS SIEVES

i) A set of IS Sieves of sizes - 80mm, 63mm, 50mm, 40mm,

31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm,

4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm, 300µm, 150µm

and 75µm

ii) Balance or scale with an accuracy to measure 0.1 percent

of the weight of the test sample

SAMPLE

The weight of sample available should not be less than the

weight given below:-

The sample for sieving should be prepared from the larger sample

either by quartering or by means of a sample divider.

PROCEDURE

i) The test sample is dried to a constant weight at a

temperature of 110 + 5 °*C* and weighed.

ii) The sample is sieved by using a set of IS Sieves.

iii) On completion of sieving, the material on each sieve is

weighed.

iv) Cumulative weight passing through each sieve is calculated

as a percentage of the total sample weight.

v) Fineness modulus is obtained by adding cumulative

percentage of aggregates retained on each sieve and dividing

the sum by 100.

REPORTING OF RESULTS

The results should be calculated and reported as:

i) the cumulative percentage by weight of the total sample

ii) the percentage by weight of the total sample passing

through one sieve and retained on the next smaller sieve, to

the nearest 0.1 percent.

The results of the sieve analysis may be recorded graphically on

a semi-log graph with particle size as abscissa (log scale) and

the percentage smaller than the specified diameter as ordinate.