Flakiness and Elongation Index Tests for Aggregate Size

The Flakiness Index and Elongation Index are important tests performed on aggregates to assess their shape characteristics. These shapes (flaky or elongated particles) are undesirable in pavement construction materials as they can lead to issues like poor workability, increased binder content requirement, and potential instability in the final mix.

However, these tests are not performed on all aggregate sizes. Standard specifications, such as those often followed in civil engineering and construction (like Indian Standards), define specific size ranges for these tests.

Applicability of Flakiness and Elongation Tests

The standard procedure for determining Flakiness index and Elongation index specifies that these tests are applicable only to aggregate sizes retained on the 6.3 mm sieve. This means that aggregates passing through the 6.3 mm sieve are considered too small for these shape tests.

• Aggregates larger than or equal to 6.3 mm are tested.
• Aggregates smaller than 6.3 mm are not tested for Flakiness index and Elongation index.

Therefore, the Flakiness index and Elongation index test is not applicable to aggregate sizes smaller than 6.3 mm.

Looking at the options provided, the size smaller than which the tests are not applicable is 6.3 mm.