Aggregate Lab Test - Sieve Analysis

TEST FOR AGGREGATES FOR CONCRETE

IS 2386-1 (1963): Methods of Test for Aggregates for Concrete, Part I: Particle Size and Shape [CED 2: Cement and Concrete]

SIEVE ANALYSIS

Object - This method covers the procedure for the determination of particle size distribution of fine, coarse and all-in-aggregates by sieving or screening.

Apparatus

Sieves - Sieves of the sizes given in Table below, conforming to IS : 460-1962 Specification for Test Sieves

IS SIEVES FOR SIEVE ANALYSIS OF AGGREGATES FOR CONCRETE

TYPE	SIEVE DESIGNATIONS
Square hole, perforated plate	80-mm, 63-mm, 50-mm, 40-mm, 31.5-mm, 25-mm, 20-mm, 16-mm, 12.5-mm, 10-mm, 6.3-mm, 4.75-mm
Fine mesh, wire cloth	3.35-mm, 2.36-mm, l.l8mm, 600-micron, 300-micron, 150-micron, 75-micron

Balance - The balance or scale shall be such that it is readable and accurate to 0.1 percent of the weight of the test sample.

Sample - The weight of sample available shall be not less than the weight given in Table below. The sample for sieving shall be prepared from the larger sample either by quartering or by means of a sample divider.

MINIMUM WEIGHTS FOR SAMPLING

MAXIMUM SIZE PRESENT IN SUBSTANTIAL PROPORTIONS	MINIMUM WEIGHT OF SAMPLE DESPATCHED FOR TESTING
mm	kg
63	100
50	100
40	50
25	50
20	25
16	25
12.5	12
10.0	6
6.3	3

Test Procedure for Coarse and Fine Aggregate

The sample shall be brought to an air-dry condition before weighing and sieving. This may be achieved either by drying at room temperature or by heating at a temperature of 100°C to 110°C. The air-dry sample shall be weighed and sieved successively on the appropriate sieves starting with the largest. Care shall be taken to ensure that the sieves are clean before use.

Each sieve shall be shaken separately over a clean tray until not more than a trace passes, but in any case for a period of not less than two minutes. The shaking shall be done with a varied motion, backwards and forwards, left to right, circular clockwise and anti-clockwise, and with frequent jarring, so that the material is kept moving over the .sieve surface in frequently changing directions. Material shall not be forced through the sieve by hand pressure, but on sieves coarser than 20 mm, placing of particles is permitted. Lumps of fine material, if present, may be broken by gentle pressure with fingers against the side of the sieve. Light brushing with a soft brush on the under side of the sieve may be used to clear the sieve openings.

Light brushing with a fine camel hair brush may be used on the 150-micron and 75-micron IS Sieves to prevent aggregation of powder and blinding of apertures. Stiff or worn out brushes shall not be used for this purpose and pressure shall not be applied to the surface of the sieve to force particles through the mesh.

On completion of sieving, the material retained on each sieve, together with any material cleaned from the mesh, shall be weighed.

Reporting of Results -

The results shall be calculated and reported as:

a) the cumulative percentage by weight of the total sample passing each of the sieves, to the nearest whole number

b) the percentage by weight of the total sample passing 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.