Hot Mix Asphalt Technology - January/February 2008 - (Page 17)

NCAT Test Track: Real-time Testing for he NCAT Pavement Test Track, constructed in 2000, was designed to be a site where pavements could be tested under real-world conditions. Five heavily loaded tractor-trailers circle the track to provide the equivalent of 15 years of wear on the pavement in just two years. Most of the test sections are sponsored by state DOTs, giving them the opportunity to test mix designs and aggregates specified by their individual highway departments. The structural design sections are used to validate and calibrate mechanisticempirical pavement thickness design using local materials. Test sections can be rebuilt every three years. Approximately half of the sections were replaced in 2003 and 2006 to allow for new tests, while some state DOTs have chosen to leave their sections intact to test the durability of their mixes over an even longer period of time. Current tests at the track are providing useful information. “The warm-mix sections are performing well, showing virtually no deformation,” said Buzz Powell, Test Track Manager. “High-RAP content mixes are also being tested and so far showing good rutting and durability performance.” Real-world Results T Five heavily loaded tractor trailers run five days a week at NCAT’s Pavement Test Track at Auburn University. The loads simulate 15 years of traffic in just two years. Facts and figures about the NCAT Test Track Length of the track: 1.7 miles Trucks: The five tractor trailers are loaded at 20,000 pounds per axle (total weight of approximately 155,000 pounds). A day at the track: The trucks travel at 45 mph, 16 hours per day, five days per week. Loading: 10 million ESALs (equivalent single-axle loadings) every two years, equal to approximately 15 years of normal traffic. Number of test sections: 46 Test Track results: Available at www.pavetrack.com. Instrumentation: Temperature and moisture are monitored continually. Strain gauges and pressure plates measure the pavements’ response to passing loads. Each truck is equipped with a wireless data logger that captures key information from the onboard computer network. Current tests: High-RAP-content mixes, warm mix, quiet pavements, open-graded friction courses (OGFC), SMA, mechanistic-empirical pavement design models, lower design gyrations, low air void mixes, and others. HMAT Buzz Powell, Pavement Test Track Manager, gives John Bobo an overview of the test track. Bobo is the acting director of U.S. DOT’s Research and Innovating Technology Administration. Powell explained how researchers work at NCAT is helping road builders enhance the quality of new and reconstructed highways. Hot Mix Asphalt Technology – JANUARY/FEBRUARY 2008 • 17 http://www.pavetrack.com

Table of Contents Feed for the Digital Edition of Hot Mix Asphalt Technology - January/February 2008

Hot Mix Asphalt Technology - January/February 2008 Contents Chairman's Commentary President's Perspective A Conversation with the New NCAT Director NCAT Test Track: Real-Time Testing for Real-World Results Warm Mix: The Lights are Green Illinois Tollway Tests RAP in Fast Forwarded Research Big Creek Teams with TxDOT to Pave Using Innovative Asphalt Mix Diamond Achievement Commendation Issues a Call for Quality Calendar of Events CONEXPO-CON/AGG Product Review Index of Advertisers Advertisers.com

Hot Mix Asphalt Technology - January/February 2008

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