ABSTRACT
Flexible pavements rely upon the contributions of all layers toward the overall structural capacity of the section. For pavements designed according to the AASHTO design procedure, the granular base and subbase layers may contribute as much as 50% of the total structural number for the section. Clearly, the performance or service life of flexible pavements will therefore be quite sensitive to the thickness and properties (resilient modulus/layer coefficient) of the unbound layers as well as to the stiffness of the underlying unbound subgrade.
