WELCOME to the home page for the NCAT Pavement Test Track.  The primary objective of this site is to effectively communicate our experiences to the world as we administer research designed to reduce the life cycle cost of flexible pavements.  Experimental mixes on our 1.7 mile oval (located about 30 minutes from the campus of Auburn University) are installed in 200 ft test sections that facilitate meaningful field performance comparisons, and laboratory testing is conducted on samples made during construction to facilitate practical lab to field performance correlations.   Anyone interested in test section sponsorship (which is open to both public and private participation) is encouraged to contact either Randy West (westran@auburn.edu) or Buzz Powell (buzz@auburn.edu) for additional information.  The fourth research cycle, which is currently under construction,  is also advertised on pooledfund.org.   We appreciate your interest and value your feedback.

CONSTRUCTION - Reconstruction activities for the 2009 research cycle are expected to be complete in July of 2009 in order to facilitate the initiation of fleet operations while summer pavement temperatures are extremely hot.  MySpace messaging will be used to post pictures and update sponsors on the status of Track reconstruction.  The schedule can change daily as a function of the weather and progess to date, so interested parties are encouraged to check back on a regular basis.

INSTRUMENTATION - Multidepth temperature thermister probes are installed in all 46 sections on the Track.  Paired with data from 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 the pavements' response to passing loads, which is useful in validating pavement analysis and design methodologies that are mechanistically based.  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.

TRUCKING - This type of research is known as accelerated performance testing (APT) because a design lifetime of truck damage (typically 10 to 15 years) is induced in 2 years.  Trucking operations are planned to begin before the end of July for the 2009 research cycle in order to challenge new pavements with high summer temperatures.   While the fleet is operational, an AM driver shift runs from 5:00 AM until approximately 2:00 PM, and a PM driver shift runs from 2:00 PM until approximately 11:00 PM.  Each rig in the 5 truck fleet targets running 680 miles per day (340 miles per driver) in order to damage experimental pavements.  Since all sections are subjected to identical and precisely monitored levels of traffic, it is possible to complete meaningful intrasponsor and intersponsor field performance comparisons.  Running so many miles in a controlled manner creates a great opportunity to conduct heavy truck research, and we are working closely with the trucking industry to meet their research needs in a manner that complements the work we do for the paving industry.  Select reports from the Program for Advanced Vehicle Evaluation (PAVE) are available for download.

FIELD PERFORMANCE - Every Monday, trucking is suspended so that vehicle maintenance can be performed and pavement performance can be quantified.  An inertial profiler equipped with a full lane width dual scanning laser "rutbar" is run weekly around the entire Track in order to determine individual wheelpath roughness, right wheelpath macrotexture and individual wheelpath rutting for every experimental section.  Additionally, 3 random locations were selected within each section in a stratified manner to serve as the fixed test location for nondestructive wheelpath densities.  Transverse profiles are measured along these same locations so that rutting may be verified using a contact method.  Falling weight deflectomer testing is typically run weekly, which is also the case with high speed structural response data collection and surface crack mapping.  Every month, wet ribbed surface friction testing is run with a full scale friction trailer.  Sound and permeability testing are run quarterly in order to characterize how the pavement surfaces are changing over time.  Cores are cut each quarter from the wheelpath of every section so that densification of each layer can be considered.

LAB PERFORMANCE - To facilitate lab to field performance correlations, a very large amount of actual plant run material is sampled at the time test sections are constructed.  This material is placed into storage and used to fabricate specimens for many different types of laboratory performance characterization.  Mix that was placed in the bottom of pavement test sections is subjected to beam fatigue and push-pull testing in order to characterize resistance to fatigue.  Mix that was placed in surface layers is subjected to dynamic modulus, flow number, APA and Hamburg testing in order to quantify resistance to permanent deformation.   Surface mixes are also subjected to overlay testing, semi-circular bending, IDT creep/strength testing and energy ratio testing in order to characterize each mix's cracking susceptibility.  Numerous other tests are run on mix constituents in order to asses their contribution to pavement performance.

COMMUNICATION - Representatives from each research sponsor are onsite while test sections are being built in order to provide oversight and ensure that as-built properties best meet their research needs.  Meetings of the entire sponsor group are hosted at the Track every 6 months thereafter in order to share preliminary results and plan for the future.  At each meeting, the first day consists of classroom presentations and discussions, while the second day is spent on the Track inspecting test sections.  The last 6-month sponsor meeting was held on February 9, 2009 in conjunction with the end-of-cycle  Track Conference.  Many reports on Track research have been published and are available for download.