Determination of the flakiness and the elongation index for the given aggregate sample.

This test is used to determine the particle shape of the aggregate and each particle shape being preferred under specific conditions.

The significance of flakiness & elongation index is as follows:

• The degree of packing of the particles of one size depends upon their shape.
• Due to high surface area to volume ratio, the flaky and elongated particles lower the workability of concrete mixes.
• Flaky and elongated particles are considered undesirable for base coarse construction as they may cause weakness with possibilities of braking down under heavy loads.
• BS-1241 specifies a Flakiness index not exceeding 30% irrespective of the aggregate size.
• Maximum permitted Elongated index is 35, 40 or 45% for aggregate sizes     2 ½’’ – 2’’, 1 ½’’ – ¾’’ & ½’’ – 3/8’’.
• Both Flakiness and Elongation tests are not applicable to sizes smaller then 6.3mm i.e. ¼’’ sieve.

Determination of the flakiness and the elongation index for the given aggregate sample.

This test is used to determine the particle shape of the aggregate and each particle shape being preferred under specific conditions.

The significance of flakiness & elongation index is as follows:

• The degree of packing of the particles of one size depends upon their shape.
• Due to high surface area to volume ratio, the flaky and elongated particles lower the workability of concrete mixes.
• Flaky and elongated particles are considered undesirable for base coarse construction as they may cause weakness with possibilities of braking down under heavy loads.
• BS-1241 specifies a Flakiness index not exceeding 30% irrespective of the aggregate size.
• Maximum permitted Elongated index is 35, 40 or 45% for aggregate sizes     2 ½’’ – 2’’, 1 ½’’ – ¾’’ & ½’’ – 3/8’’.
• Both Flakiness and Elongation tests are not applicable to sizes smaller then 6.3mm i.e. ¼’’ sieve.