The following pavement has been proposed for a new road:
Hot-Mix Asphalt E = 500,000 psi Thickness = 5"
Cement Treated Granular Base, unconfined compressive strength = 600 psi, Thickness = 6"
Untreated Granular Subbase, CBR = 30%, fair drainage 5% of time exposed to moisture levels
approaching saturation, Thickness = 6"
A. Estimate the Structural Number of the pavement (for the entire pavement structure,HMA+base+subbase)..
B. Using the SN computed in part A; how many ESAL’s can the pavement carry on average if you use an initial PSI of 4.5 and a terminal PSI of 2.5 and no environmental effects are considered and it is built on a subgrade with an effective resilient modulus of 10,000 psi?
C. What thickness of HMA would be required to carry the same traffic (computed in B) if there is a loss of serviceability due to frost heave of 0.8? Assume that the thickness other two layers would not be changed.
D. Using the original pavement structure (SN computed in part A), what would be the reliability if the expected traffic over the design period is 1x107 ESALs and s0 =0.45. Would it be appropriate if it is a primary rural arterial road?