28.4. Failure Criteria

Try these first

1. 1.

   What are the critical locations in a flexible pavement where strains are assessed?

   Hint

   Think about where the binder and sub-grade are located in the pavement.

2. 2.

   What happens if tensile strains exceed the allowable limits?

   Hint

   Consider what tensile strains can cause to the pavement layer.

3. 3.

   What is the main focus of the 'Failure Criteria' section?

   • Material properties
   • Stress points in pavements
   • Pavement aesthetics

   Hint

   Think about what criteria are needed to prevent pavement failures.

4. 4.

   True or False? Exceeding tensile strain limits can lead to fatigue cracking.

   • True
   • False

   Hint

   Remember the specific limits outlined in the section.

5. 5.

   Given a scenario where the tensile strain at the bottom of the bituminous layer reaches 300 microstrain, calculate the expected number of load repetitions permitted before significant fatigue cracking occurs using the criteria provided.

   Hint

   Refer to the fatigue criteria equation described in the section.

6. 6.

   Imagine a flexible pavement designed for a high-traffic urban area. Draft a plan detailing how you would manage both tensile and compressive strains over its lifespan.

   Hint

   Consider traffic analysis data along with the pavement design specifications.