Surface course: 12.5 mm (0.5 inch) Superpave with E = 3,447 MPa (500,000 psi)Binder course: Dense-graded HMA mix with a nominal maximum aggregate sizeof 25 mm (1 inch). Investigate 20, 30 and 40 year design periods

Some of the illogical results obtained from the sensitivity analyses were also addressed.Assume 80% of the loading occurs in the design lane

The sensitivity analysis included different amount of traffic loads, base materials, base material thicknesses, surface/slab layer thicknesses and subgrade materials. Several important design parameters were selected and were varied one at a time and their effect on the pavement distresses was found. In this report, sensitivity analyses were conducted of the new AASHTO 2002 method for both flexible and rigid pavements, to understand its performance with respect to the various design parameters. To overcome these limitations AASHTO finally proposed the AASHTO 2002 design guide which is based on mechanistic empirical approach and serves to address the shortcomings and limitations of the earlier empirical design equations developed from the Road Tests. For example, the traffic loads and truck sizes have increased over the years, the AASHTO design equations were derived based on the climatic conditions present at the Road Tests site, and the issue of aging materials was not addressed in the design. The various editions of the AASHTO pavement design guide have served well for several decades nevertheless many serious limitations existed for their continued use as the nation's primary pavement design procedure. Over the years pavement design has been based on empirical equations developed from the American Association of State Highway Transportation Officials (AASHTO) road tests.

Flexible pavement design aashto example