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April 2008
Conference speakers offer a green approach to pavement
The home page for the “Green Roads” rating system
Asphalt is black and concrete is gray, but “green” is becoming the new look for pavement as environmental concerns grow in importance. Speakers at the 12th Annual Minnesota Pavement Conference described emerging areas such as green roads and greenways, warm-mix asphalt, and sustainable innovations in concrete pavements.
The conference, held February 14 in St. Paul, was sponsored by Mn/DOT, the Minnesota Local Technical Assistance Program (housed at CTS), and a number of other organizations. The event began with opening comments by Lisa Freese, Mn/DOT deputy commissioner.
Current road-building and road-use practices are primary sources of environmental degradation, said Joe Mahoney, a civil engineering professor at the University of Washington. He provided an overview of “Green Roads,” a proposed rating system being developed by the University of Washington and CH2M Hill to improve the sustainability of roadway design and construction practices.
Ramsey County commissioner Victoria Reinhardt and staffer Bridget Beck described components of a short but vital segment of a bike and pedestrian trail in the Twin Cities’ trail system. The project used a number of recycled products, including tear-off roofing shingles in the bituminous mix, recycled plastics in the retaining wall and benches, and reused sand in rain gardens.
Dave Newcomb, vice president of research and technology with the National Asphalt Pavement Association (and former MnROAD research director and professor with the University of Minnesota’s Department of Civil Engineering), explained how construction using “warm-mix” asphalt—as opposed to the standard hot mix—decreases both fuel usage and emissions.
Mark Snyder, an engineering consultant with Geotech Innovations (and another former CE faculty member), gave an update on an FHWA-sponsored study of concrete pavements constructed using recycled concrete aggregate.
Several University of Minnesota researchers reported on their work. Gene Skok, retired from the CE department, described a project he and Shongtao Dai of Mn/DOT conducted with funding from the Minnesota Local Road Research Board (LRRB). The objective was to lay out best practices for the selection of asphalt concrete recycling techniques. The report, MnPavement Rehabilitation Best Practices (2008–06), will be available on the LRRB.
Professor John Nieber of the Department of Biosystems previewed another LRRB-funded project, this one a subsurface drainage manual for pavements. The project was based on an idea from Tim Anderson and Glenn Engstrom of Mn/DOT’s Maintenance Research Office submitted through the CTS problem statement process, Nieber said. The manual is scheduled for publication this fall.
Michael Darter, director of the Pavement Research Institute at the University of Minnesota, discussed a major project funded through the second Strategic Highway Research Program (SHRP 2) that will investigate the design and construction of new composite pavements (see January 2008 CTS Report for details).
The conference also included the presentation of the annual Jerry Rohrbach Pavement Conference Award to Doug Schwartz of Mn/DOT’s Concrete Engineering Unit.
The conference planning committee included several University representatives: Jim Grothaus, director of Minnesota LTAP; Darter and Skok; and Lori Graven and Teresa Washington from the College of Continuing Education.
Coverage will be published later this spring in the 2008 Minnesota Pavement Conference Session Summaries, available for download on the Minnesota LTAP Web site at www.mnltap.umn.edu/Publications.