New Funding Sought To Continue Taking Superpave Technology on the Road

For some years now, mobile asphalt testing laboratories operated by the Federal Highway Administration (FHWA) have crisscrossed the country, providing hands-on training and technical support in designing and building Superpave pavements. To date, the two labs, each staffed with a team of technicians and outfitted with state-of-the-art mix design and testing equipment, have been put to use at 57 project sites in 33 States. They have also been showcased at more than 15 conferences. The labs allow highway agency staff, contractors, and asphalt suppliers to learn and experiment with the mix design procedures that form the core of the Superpave system. 

Steve Niederhauser of the Utah Department of Transportation (DOT) says of his State’s experience with the labs, "It was excellent. We got to see the equipment in action, and we got to talk to the people who worked on it. I would like even more hands-on experience with the lab equipment." 

FHWA planned to continue operating these labs to ensure that State agencies and industry everywhere can learn how to use—and benefit from—the Superpave mix design system. The labs are scheduled to travel this spring to Alabama, Alaska, Arizona, California, Idaho, Michigan, and Washington State. Last year’s passage of the Transportation Equity Act for the 21st Century (TEA-21), however, put the labs’ future in peril, as the act’s reallocation of highway funds means that FHWA no longer has the funds to support and operate the labs under Demonstration Project Number 90 (DP-90). 

Recognizing the value of the labs—and the void created without them—the American Association of State Highway and Transportation Officials (AASHTO) Task Force on SHRP Implementation recommended they be continued under the aegis of the National Cooperative Highway Research Program (NCHRP). The task force’s recommendation will be considered by the AASHTO Standing Committee on Research at its meeting this month. 

The task force chairman, John Conrad of the Washington State DOT, recently observed, "We’re at a crucial time in the deployment of Superpave technologies. The States are in the middle of moving from the theoretical world of the labs to the real-world problems of the field, and the labs are a key part of making that movement successful. To drop them now would leave a big hole in Superpave implementation." 

In addition to being one of the primary tools for demonstrating Superpave mix design to State highway agency personnel and to contractors, the mobile labs also play a critical role in the development of quality control/quality assurance (QC/QA) test procedures. For two NCHRP projects over the past 5 years, the mobile labs have performed onsite testing of tools needed to evaluate hot-mix asphalt performance. The benefits of these advanced QC/QA procedures—used by States and FHWA alike—will also be lost if funding for the labs is not found. NCHRP has six new projects just getting underway where the mobile labs will be needed. 

FHWA’s mobile asphalt laboratories are not just for training: 

• Data collected during field demonstrations are used in refining the Superpave system, such as adjusting the aging procedure. 
• The labs have served as testing grounds for new models of gyratory compactors, to ensure they meet Superpave specifications. 
• A procedure developed in the labs led to AASHTO test procedure T287, Asphalt Cement Content of Asphalt Concrete Mixtures by the Nuclear Method. 
• The labs gathered and verified data critical to creating the quality control/quality assurance (QC/QA) test procedures developed under NCHRP Project 9-7, Field QC Methods for Superpave. The resulting database is used by State highway agencies and contractors to track production data and by researchers in the development of software.