Going green: Preserving Illinois roadways with recycled asphalt

Sustainability is key to a greener future. Our pavements are no different.

Greener roads are one step closer thanks to a joint Illinois Center for Transportation and Illinois Department of Transportation project, “R27-SP56: Utilizing Reclaimed Asphalt Pavement in Preservation Treatments.”

Imad Al-Qadi, ICT director and University of Illinois Grainger Distinguished Chair in Engineering, and Ramez Hajj, UIUC assistant professor, led the project with John Senger, IDOT’s Bureau Chief of Research.

To reduce the impact on our climate, the three explore using reclaimed asphalt pavement — or recycled asphalt — in pavement preservation, a technique for which IDOT hopes to start using recycled materials while maintaining performance.

Pavement preservation adds a lift, or layer, to the pavement surface to preserve the road surface from environmental damage while extending its service life.

“The U.S. is shifting from building new roads to rehabilitation and preservation,” Al-Qadi said. “At the same time, we have excess RAP material in some Illinois districts, so we are trying to use it as part of preservation to enhance the sustainability of our roadway construction.”

Advantages of using RAP in preservation include cost savings, reducing emissions from producing and hauling materials, and re-using materials already accumulated in plants.

Illinois had 3.9 million tons of RAP stockpiled at contractor plants in 2018, according to data from the National Asphalt Pavement Association.

Al-Qadi and Hajj’s team explored current methods and approaches used for RAP preservation as well as its feasibility in Illinois.

They investigated the cost associated with using RAP for pavement preservation as well as its environmental impact.

“We found this to be cost-effective as well as to have a positive impact on the environment by reducing global warming,” Al-Qadi said.

The project is a “first step” to understanding the feasibility of using recycled materials in pavement preservation in Illinois.

Next steps involve exploring the real-world performance of RAP, which is made possible by a recent upgrade to ICT’s Accelerated Transportation Loading Assembly.

“The new ATLAS is designed to allow us to test preservation materials, which no other facility in the world can do,” Al-Qadi said.

“The new design will allow us to test acceleration and deceleration and turning, all of which affect the surface, so that we may test RAP in the future under close-to-real-life conditions,” he added. “We are very well prepared now to test this in the field and take it to the next level of research.”