(Solved): 2. An interstate highway pavement composed of a HMA surface course, a cement treated base course, a ...

2. An interstate highway pavement composed of a HMA surface course, a cement treated base course, and a sand-gravel subbase is to be designed for an ESAL of $1.2\times 10^6$. The quality of drainage is considered fair because water can be removed from the subbase within a week. However, there is a large amount of precipitation, so more than $25\%$ of the time the pavement will be exposed to moisture levels approaching saturation. The material properties are as follows: effective roadbed soil resilient modulus $=5500\mathrm{psi}$, resilient modulus of subbase $=15,000\mathrm{psi}$, unconfined compressive strength of cement-treated base at 7 days $=500\mathrm{psi}$, and resilient modulus of $\mathrm{HMA}=4.3\times 105$ psi. Assuming a minimum thickness 5 for HMA, determine the thicknesses of the surface, base, and subbase courses required.