5.4.6. Flakiness and Elongation Index Test

Try these first

1. 1.

   What are flaky aggregates?

   Hint

   Think about the relationship between thickness and the average size.

2. 2.

   How do you determine if an aggregate is elongated?

   Hint

   Remember the ratio we discussed.

3. 3.

   What indicates that an aggregate is classified as flaky?

   • Thickness < 0.6 × mean size
   • Length > 1.8 × mean size
   • Thickness > mean size

   Hint

   Think about how thickness relates to the standard of 0.6.

4. 4.

   True or False: Elongated aggregates are desirable in concrete mix.

   • True
   • False

   Hint

   Recall what elongation means in the context of shape.

5. 5.

   Given a sample aggregate with 30% flaky particles and 50% elongated particles, discuss the potential impacts on a concrete mix's performance.

   Hint

   Visualize how these shapes interlock when mixed.

6. 6.

   Design an experiment to compare the performance of concrete made with standard aggregates versus those with high flakiness and elongation indices.

   Hint

   Think about variables you might need to control in your mixes.