Test Track

Arial view of entire NCAT Test TrackLocated on a 309-acre site, NCAT’s Test Track is a 1.7-mile oval where research is conducted on experimental asphalt pavements. The track is comprised of 46 200-ft test sections funded as a cooperative project among highway agencies and industry sponsors. Research experiments based on single test sections or groups of test sections provide sponsors the confidence to move concepts into practice, saving state departments of transportation millions of dollars each year.

Test Sections

Sections can be classified as either structural experiments, surface mix experiments, or pavement preservation studies. Performance is monitored on a continuous basis to evaluate rutting, fatigue cracking, roughness, texture, friction and noise. Structural pavement sections have varying thicknesses that closely resemble real-world pavements. They have embedded strain and pressure sensors that analyze pavement response to loads for validation of mechanistic-empirical pavement design procedures. Surface mix performance sections are built on a robust cross-section that limits distresses to the experimental surface layers.

Multidepth temperature probes are installed in each test section. Paired with an onsite automated weather station, these data are used to precisely characterize the performance environment for each experimental section. Additionally, the sections that make up the structural experiment have high speed instrumentation arrays consisting of strain gauges and pressure plates installed at select depths. Measurement data generated by these devices are used to quantify pavement response to passing loads to validate pavement analysis and mechanistically based design methodologies. A wireless mesh network has been deployed along the entire length of the Track to facilitate high speed data transfer in a safe and efficient manner.

Research Cycles

The first phase of a research cycle consists of constructing test sections on and off the Test Track. Representatives from research sponsors make on-site visits during this phase in order to ensure that the sections satisfy their research needs. To facilitate lab to field performance correlations, a large amount of mixture samples from construction are tested and analyzed in the laboratory. Various parameters are also measured during the construction process to capture in-place properties of the sections. 

In the second phase, each section on the track is subjected to 10 million equivalent single axle loads (ESALs) of heavy truck traffic applied over a period of two years. This method of accelerating trafficking allows researchers to deliver cutting-edge test results to state highway departments at an extraordinary speed. The performance of each track section is closely monitored on a weekly basis. An automated pavement distress data collection vehicle is used to quantify roughness, macrotexture, rutting, and cracking in the same manner used by most state highway departments for their pavement management systems. Other tests such as surface friction, falling weight deflectometer, sound, and permeability are also conducted. Similar performance data is conducted on the off-track sections, but due to the open traffic on these roadways, data collection is conducted on a less frequent basis than the closed-loop track.

The final part of the three-year cycle involves forensic analyses of damaged sections on the test track in order to determine the contributing factors to pavement distresses. Many forensic investigations conducted during this stage include destructive testing such as trenching and coring. At the end of each cycle, test sections either remain in place for additional evaluation during the next cycle or are replaced.

The sixth cycle of accelerated performance testing began in 2015, providing unique opportunities to determine the field performance of breakthrough materials and concepts without the risk of failure that local and state agencies are unwilling to accept. NCAT is at the forefront of research to quantify the life-extending benefits of pavement preservation treatments. The scope of pavement preservation research has been expanded in this cycle to include continued evaluation of Lee County Road 159, a low volume route, and 40 new treatment sections on U.S. Route 280, a much higher traffic volume roadway. NCAT is also partnering with the Minnesota DOT to conduct full-scale pavement testing at its MnROAD facility to meet national pavement research needs in hot and cold climates.

Beyond Pavement Testing

The track is also used for a variety of transportation-related projects including the development of new heavy vehicle suspension systems, truck platooning, evaluation of alternative fuels, improved tires, a vehicle rollover prediction system, advanced propulsion systems, and improved vehicle electronics and safety.

Tracks Worldwide

Other accelerated pavement testing facilities in the United States and around the world can be found here.