The Grainger College of Engineering
Illinois Center for Transportation

New ICT-IDOT reports

9/19/2025 McCall Macomber

Illinois Center for Transportation is pleased to announce the publication of reports from the following Illinois Department of Transportation-sponsored projects, in order of publication.

R27-250: Using Advanced Binder Rheological Parameters to Predict Cracking Potential of Hot-Mix Asphalt Mixtures with Modified Binders
Imad Al-Qadi, University of Illinois Urbana-Champaign
Kelly Senger and Brian Hill, Illinois Department of Transportation

Asphalt binder in a shear mixer with a researcher adding polymer to it
Asphalt binder is an adhesive that holds aggregates, such as gravel or crushed stone, in pavement together. As asphalt binder ages, it becomes more prone to cracking, affecting the life span of the asphalt pavement layer.

This project sought to improve the asphalt binder used in hot-mix asphalt pavements to increase the performance and durability of pavements constructed in Illinois.

Improved pavement performance and durability may allow Illinois drivers to experience less maintenance activities and fewer construction projects over a pavement’s lifespan. Researchers evaluated a combination of softener and styrene-butadiene-styrene modifiers to determine the combination’s viability in asphalt binder and mixture tests.

The research also developed a tool to predict mixture cracking resistance using asphalt binder properties.

R27-SP72: Field and Lab Evaluation of Roller-Compacted Concrete Mixtures for Pavements
Jeffery Roesler, University of Illinois Urbana-Champaign
John Senger, Illinois Department of Transportation

Provided by John Senger. A roller-compacted concrete pavement in Jerseyville, Illinois.
Provided by John Senger. A roller-compacted concrete pavement in Jerseyville, Illinois.

Applications of roller-compacted concrete pavements have primarily included industrial and port facilities, with recent applications expanding to parking areas, exterior lots of commercial warehouses, residential streets and lower volume roads.

This project evaluated the mixture volumetrics of an IDOT RCC pavement project through field and lab observation and testing as well as evaluated local sources for a potential RCC pavement at the Illinois Certification and Research Track.

R27-SP74: Evaluation of Concrete Overlays
Jeffery Roesler, University of Illinois Urbana-Champaign
Charles Wienrank, Illinois Department of Transportation

A longitudinal crack on an Illinois highway.
Longitudinal cracking on an Illinois highway that has been rehabilitated with an unbonded concrete overlay.

Existing concrete pavements that have reached the end of their service life may be rehabilitated using an unbonded concrete overlay — where a new concrete surface layer is placed over existing pavement.

Researchers assessed the performance of three projects with unbonded concrete overlays in Illinois through visual surveys, nondestructive testing and coring. The assessments provided current overall overlay performances, structural condition, and the potential interlayer condition and interfacial contact integrity.

The results are expected to assist in developing or modifying specifications and standards for the design, construction and maintenance of unbonded concrete overlays.