$[$Problem $1]$

A flexible pavement for an urban interstate highway is to be designed using the AASHTO method to carry a design ESAL of $3$ x $106.$ It is estimated that it takes about a WEEK for water to be drained from within the pavement and the pavement structure will be exposed to moisture levels approaching saturation for $30\%$ of the time. The following additional information is

available:

Elastic modulus of asphalt concrete $=450,000$ psi

Resilient modulus of base material $=35,000$ psi

Resilient modulus of subbase material $=15,000$ psi

CBR of subgrade material $=8$

$[$Problem $2]$

$($a$)$ Consider designing the same pavement with only asphalt concrete and base layer $($excluding subbase layer$).$ Use the information provided in Problem $1.$

$($b$)$ Compare strengths and weaknesses of each design.

HINT: the solutions are $-$ Problem No$.1$

D$1=6\mathrm{.}5-$in$.$

D$2=6-$in$.$

D$3=4-$in$.$

Problem No$.2$

D$1=6\mathrm{.}5-$in$.$

D$2=9-$in$.$