28.3. Design Criteria

Try these first

1. 1.

   What are the three main layers of flexible pavements?

   Hint

   Recall the acronym SBS.

2. 2.

   What strain occurs at the top of the sub-grade?

   Hint

   Think about vertical deformation.

3. 3.

   What are the three layers of flexible pavements?

   • Granular
   • Base
   • and Sub-grade
   • Base
   • Bituminous
   • and Aggregate
   • Sub-grade
   • Granular
   • and Bituminous

   Hint

   Think about the structure of flexible pavements.

4. 4.

   True or False: Horizontal tensile strain can cause cracking in the upper layers of flexible pavements.

   • True
   • False

   Hint

   Recall how strain affects pavement.

5. 5.

   Calculate the allowable vertical compressive strain if the sub-grade's maximum limit is defined as 0.5% for a new pavement design.

   Hint

   How does this influence your design decisions?

6. 6.

   Discuss the implications of exceeding the horizontal tensile strain limit in bituminous layers within a pavement design.

   Hint

   Consider why maintaining strain limits is crucial for pavement longevity.