Theory

1. The flakiness index of aggregate is defined as the percentage by weight of the particles of aggregate whose least dimension is less than 0.6 of their mean dimensions.

2. During the construction of roads, flaky particles are considered undesirable because they get broken easily upon the application of load. This may result in the failure of roads with the development of cracks over their surface. Thus, it is necessary to find out the flakiness value of aggregates to account for their suitability in concrete structures and highway construction.

3. The flakiness index should be less than 15% during pavement construction and normally it should not exceed 25%.

4. By conducting Flakiness Index tests, engineers can select aggregates that meet the specified shape requirements, resulting in improved concrete workability, strength, and overall project quality. Moreover, the test aids in minimizing waste and optimizing material usage contributing to costeffectiveness and sustainability in construction practices.

The flakiness index of a given sample of coarse aggregate is calculated by using the following formula:

Flakiness index = B/A×100

where, A is the total weight of sample taken B is the total weight of material passing through various slots in a thickness gauge

Apparatus

1. Balance,
2. Thickness gauge,
3. Sieves of size 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 & 6.3 mm.