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One more load: November-December 2014

Coming to a close – 5th Cycle of NCAT Test Track analyses Sustainable Technologies and Pavement Pres


November 27, 2014
By Christine Riggs and J. Richard Willis

Topics

The National Center for Asphalt Technology’s Pavement Test Track at
Auburn University is a 1.7-mile oval proving ground where research is
conducted on experimental asphalt pavements.

The National Center for Asphalt Technology’s Pavement Test Track at Auburn University is a 1.7-mile oval proving ground where research is conducted on experimental asphalt pavements. The Test Track comprises 46 test sections sponsored on three-year cycles. Having just completed its fifth cycle of accelerated performance testing, the track uses a five-truck fleet to apply over a decade of typical interstate traffic in only two years. This method of accelerating trafficking allows researchers to deliver cutting-edge test results to state highway departments at an extraordinary speed.

The 2012 Test Track was the most ambitious experiment to date. One of the most exciting studies at the Test Track is known as the Green Group experiment that has a focus on sustainability. The study involves optimizing the use of recycled materials such as reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS), and ground tire rubber (GTR) in conjunction with warm mix asphalt. Not only were these mixtures to be assessed for performance, but the environmental and fiscal advantages of these mixtures would be quantified using life-cycle assessment and life-cycle cost analysis, respectively. One test section was designed using as much recycled tire rubber as possible. Instead of ending up in a landfill, ground rubber from used tires is being incorporated into asphalt pavements. This provides a win-win situation in terms of waste disposal and long lasting roadways. The objective is to lower roadway construction costs by increasing the amount of recycled tire content while also extending pavement life.

The Test Track is a unique real-world laboratory which allows for pavement experimentation while avoiding dangerous and costly mistakes on actual roadways. “We can do high-risk tests here that the Alabama Department of Transportation would never try on the interstate, such as building a section using as many [recycled and reclaimed] tires as possible,” explains Test Track Manager Dr. Buzz Powell. “We did something in that section that no one has ever done, and we believe it will lead to a significant change in paving practices.”

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Sponsored by four state Departments of Transportation as well as the Alabama Department of Environmental Management, the Green Group experiment is the result of a unique partnership which aims to reduce waste and maximize taxpayer dollars. The results from this groundbreaking study could tremendously increase the amount of recycled material usage and improve pavement performance.

Another one of a kind experiment developed for the 2012 Test Track is the Preservation Group experiment. As budgets are tight for state agencies, they still have the need to keep aging pavements in good condition for the driving public. When applied at the right time, pavement preservation treatments such as chip seals, micro surfacing, and thin asphalt overlays can restore a smooth, safe driving surface while saving money on future rehabilitation costs. Seven state agencies and the Foundation for Pavement Preservation sponsored test sections on the Pavement Test Track and Lee Road County 159. Twenty-five different pavement preservation treatments were placed on test sections with varying levels of distress to determine the life-extending benefits of each pavement preservation treatment.

On March 3-5, 2015, the 5th NCAT Pavement Test Track Conference will be held at the Hotel at Auburn University and Dixon Conference Center in Auburn, Alabama. The scope of this conference will include an overview of the research findings from the 1.7-mile track’s 2012-2015 cycle, an overview of preventive maintenance treatments on Lee County Road 159, an update of work at other accelerated loading facilities, and performance presentations on new materials such as warm-mix asphalt, recycled asphalt shingles, and high reclaimed asphalt pavement content mixes. Participants will have an opportunity to tour the Pavement Test Track and Lee County Road 159 while learning how NCAT’s research translates into implementable findings.

Those interested in operations at the Test Track and its upcoming conference can visit the official website at pavetrack.com or ncat.us.

christine 
Christine Riggs
 
willisrichard 
 J. Richard Willis 

One More Load is an opportunity for people from throughout the Rock to Road industry to discuss an issue that is impacting their business.
 
If you wish to make a submission for the One More Load column, please email Rock to Road Editor Andrew Macklin at amacklin@annexweb.com.


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