Question 1

Assess the importance of the thickness of the bituminous layer and road base on the pavement fatigue life.

Clarification:

You can use Sensitivity analysis

Question 2

For the pavement structure considered, develop an overlay design chart based on the following assumptions:

- The minimum overlay thickness is 5 cm and the maximum is 20 cm.
- The effective modulus of the surface layer (existing bituminous layer + overlay) may vary with regard to the existing condition and the materials to be used with typical values of 1000, 2000, 3000 and 5000 MPa.

- The subgrade strength is considered equal to the average value found in question 3 above.

- The performance of the overlaid pavement is described in terms of fatigue only.

- The expected traffic will not exceed 50 msa.

Clarifications:

Question 3

Compare the results found under Question 2 with those from RN31 and the AASHTO method. For any data that is not given you should make your own justifiable assumptions.