The Louisiana Transportation Research Center (LTRC) teamed up with The Transtec Group to develop a best practices document for achieving optimal pavement smoothness that uses the International Roughness Index (IRI) as a guide.
This is significant, as the LTRC says states “are moving away from profilograph-based smoothness specifications” and opting for IRI. The group says the report, Best Practices for Achieving and Measuring Pavement Smoothness, A Synthesis of State-of-Practice, will “help contractors, agencies and engineers adjust to the change.”
While the group says 78 percent of U.S. state asphalt pavement specifications and 46 percent of concrete pavement specifications are based on IRI, there still is some uncertainty about specifications.
“Unfortunately, a limited history with the usage of IRI-based specifications has led to some confusion over how best to structure a specification in terms of test methods and profiling equipment, thresholds for full pay/incentive/disincentive, and requirements for localized roughness or ‘must correct’ areas,” the report’s beginning abstract states.
The report covers best construction practices, smoothness specifications, collection and processing technology for IRI, current research and practices for education and training.
Best Practices for Achieving and Measuring Pavement Smoothness, A Synthesis of State-of-Practice is available here.