ICT Director Helps Organize, Gives Keynote at Gulf Conference on Roads in Qatar

Similar to other Persian Gulf countries, Qatar has experienced rapid economic and industrial growth that has resulted in an urgent need for the development and implementation of major transportation projects. Therefore, Qatar was an appropriate host for the 4th International Gulf Conference on Roads on November 10-13, 2008. ICT Director Imad Al-Qadi served on the scientific committee and gave a keynote address titled, "Towards Long Lasting Pavements in the Gulf." Associate ICT Director Sam Carpenter also attended the conference.

Flexible pavements in hot-weather regions are especially susceptible to severe "near-surface" deterioration, including near surface-initiated cracks and permanent deformation (rutting). As a result, creating long-lasting and smooth-riding pavements for these regions is a serious challenge and one of the reasons this conference was initiated.

Al-Qadi's presentation stressed that the mechanistic-empirical design of long-lasting flexible pavements in hot regions must consider accurate tire-pavement interaction, material properties, accurate numerical modeling, and full-scale testing. However, he says, the current flexible pavement design criteria only accounts for circular loading, inflation pressure equivalent to contact stress, elastic materials, and stationary loading. Unfortunately, these assumptions are inconsistent with realistic loading conditions and may result in erroneous pavement response calculation and pavement performance predictions; especially in hot regions.

To counter the aforementioned shortcomings of current flexible pavement design criteria, Al-Qadi introduced a well-developed three-dimensional finite element model and presented new research on the shear strain/stress distribution and its effect on HMA performance, which will lead to more appropriate layer stiffness design regarding shoving/rutting in flexible pavements. The end result of these developments will be longer-lasting, durable, and smooth-riding pavements in hot regions, which are especially threatened by rutting/shoving and "near surface"-initiated cracking.