Illinois Center for Transportation is nearing completion of a $1.3 million upgrade to its accelerated pavement testing system, the Illinois Accelerated Pavement Tester.

I-APT, originally acquired in 2002, is an accelerated pavement testing device that simulates real-life, long-term pavement loading conditions using truck, aircraft or rail loads over a span as short as a few months.

Benefits of APT include better predicting pavement performance, optimizing pavement design, validating new roadway technologies and increasing the benefit-cost ratio.

“At the time the system was purchased, it was the longest moveable APT in the world,” said Imad Al-Qadi, ICT director and CEE Grainger Distinguished Chair in Engineering.

“Over the past 20 years, it has been used significantly in many projects, but it was time to upgrade the system in order to meet current needs,” he added.

Key upgrades to the system will make the device the first of its kind by allowing users to select between single or tandem axles, apply acceleration or deceleration, and rotate the axle up to 6 degrees of yaw.

“There are many different APT systems that exist around the world. They are all different in size, the way they apply the load and their capacity,” Al-Qadi said. “Our upgraded APT has characteristics that make it completely unique and able to perform specialized testing unthought of earlier.”

Users may now test using single, dual, wide-base or aircraft tire configurations as well as select between single or tandem axles, with the option to change the axle spacing and wander tracking.

They can also apply shear force, or acceleration or deceleration, to simulate skidding on pavement. This upgrade will be key for testing varied torque, or rotational force applied on pavement from electric trucks, as well as testing pavements with preservation treatments under high shear loading.

It will allow loading at a yaw angle up to 6 degrees, which is the angle between the direction a vehicle is moving and the direction a vehicle is pointed to simulate lateral force.

Other key upgrades include a new control system that allows users to move the winch, axle, sheer and wander of the device remotely as well as a new hydraulic power system that will minimize electrical noise interference to allow for more accurate readings from sensors embedded in the pavement.

ICT will hold a launch event after assembly is complete.

After assembly, ICT researchers will use the device in the ICT and Illinois Department of Transportation projects, “R27-216: Optimizing the Use of Local Aggregates in Stone-Matrix Asphalt” and “R27-252: Impact of Commercial Electrical Vehicles on Flexible Pavement Performance.”

“We’re excited,” Al-Qadi said. “I-APT is a really complex system, and we are so thankful to everyone who has been involved in the upgrade process.”

“We have received tremendous support from IDOT and the University of Illinois to see this project come to realization,” he added. “IDOT’s John Senger, LaDonna Rowden and Megan Swanson have been instrumental.”

Al-Qadi also credits the effort’s success to the various personnel who assisted: ICT research scientists Greg Renshaw, Uthman Mohamed Ali and Mohsen Motlagh as well as Tim Prunkard, Steve Quenneville and Keith Epstein.