ForConstructionPros.com

Illinois Tollway's current multi-billion dollar Congestion-Relief Program, which will rebuild and expand the entire 274-mile system, is a massive undertaking that will not only improve safety and traffic flow, but one that clearly demonstrates the research benefits of constructing more sustainable and economical hot-mix asphalt pavements and overlays.

Local HMA industry contractors/supplies, other transportation agencies and universities encouraged the Tollway to research ways to construct more economically sustainable HMA pavements and overlays to be used in the rebuilding and expansion of the system.

With the ever-rising cost of materials (particularly that of liquid asphalt cement binder) and the reduced supply of some materials (particularly that of high-quality virgin aggregates), the Tollway's research efforts focused on increasing the use of reclaimed asphalt pavement (RAP) in the construction of the improved system.

On one particular project, the $180.2-million reconstruction and widening of a 16-mile section of the Jane Addams Memorial Tollway (I-90) near Rockford, IL, project engineers expect to save approximately $10 million by designing asphalt mixes with a high RAP content.

The HMA industry, as well as the contractors working on the project, worked with the Tollway to research the sustainable solution with little expense to the road agency.