August 13th, 2012
IC DEMOOptimize Mobility, by Catherine Higgins.
UDOT recently hosted an FHWA demonstration of Intelligent Compaction.
US 89 and SR 180 in UDOT Region Three is the first of nine projects locations from across the country to employ and evaluate Intelligent Compaction. The data collected and experience gained by studying IC will eventually determine if the sophisticated construction method effectively takes the guess-work out of compacting asphalt pavement.
IC systems are similar to regular asphalt pavement compactors but equipped with GPS to determine the location and number of passes and sensors to determine the temperature and stiffness of the pavement. As the compactor makes passes over the newly installed asphalt, stiffness measurements are integrated with the GPS information on a display that gives the operator a comprehensive near real-time picture of the compaction process.
The system creates an animated, color-coded online map so the compaction process can be monitored. The animation can also be played back for review.
Although the process measures pavement stiffness, the intent of the project is to correlate stiffness with pavement density, which is critical when it comes to longevity of the pavement, explains Lee Gallivan, Asphalt Pavement Engineer with FHWA. “Compaction is really the central part of the performance of the pavement.”
“You can have a real great mix design that meets all the Superpave requirements,” explains Gallivan, but with poor compaction, the pavement will not achieve appropriate density and meet the test of time. Conversely, a poor or mediocre mix design can be compacted well, and that pavement may last a long time. Extending the life of pavement “is where the public gets its money’s worth.”
Over the next two years, FHWA will sponsor IC demonstration projects in diverse parts of the country. The IC measurements will be correlated to nuclear gauge or coring density tests. The data collected from the geographically disparate projects will provide information about different mix designs, environments, substrates and traffic levels. Eventually, IC could become an accepted method for quality-control and quality-assurance for contractors and departments of transportation.