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 extend the life 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.  We appreciate your interest and value your feedback.   While you are here, we would appreciate you taking the time to participate in a brief  web survey that will help us to propose effective experiments for the 2009 Track.

CONSTRUCTION - Reconstruction of the 2006 experiment was completed on October 19, 2006 by East Alabama Paving, who was selected as the contractor via a competitive bidding process on 8/15/06.  The third research cycle again consists of extended traffic sections, new mix performance sections, and instrumented structural sections (on the Track as well as on remote, open roadways).  The instrumented structural sections are part of a larger, multi-state validation effort for mechanistic-empirical pavement design.  Fleet operations began on November 10, 2006 after finish work (shoulders, striping, etc.) had been completed and the trucks were ready to roll.  Another 10 million ESALs is planned to be completed by the fall of 2008.  The planning process is now underway for the fourth research cycle, which will be built in 2009.

INSTRUMENTATION - Multidepth temperature thermister probes have been 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 we apply a design lifetime of truck traffic (typically 10 to 15 years) in 2 years.  Over 3.3 million miles had been safely driven on the NCAT Track by the end of 2005 in order to apply 20 million ESALs over 2 traffic cycles.  Trucking operations were completed for the 2003 Track on 12/17/05, and began again in November of 2006 following the completion of reconstruction activities.  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 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 calculated using a contact method.  Every month, wet ribbed surface friction testing, falling weight deflectometer testing, and structural high speed response data are collected, along with videologging to provide a permanent visual record of surface performance.  Every quarter, cores are cut from the wheelpath of every section so that densification of each layer can be considered.

LAB PERFORMANCE - To facilitate lab to field performance correlations, numerous test specimens were compacted using actual plant run material at the time test sections were constructed.  Additionally, hundreds of pounds of loose mix were sampled and saved during production of each experimental section to facilitate other research projects that can be enhanced by being plugged into Track research.

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 November 6 and 7, 2007.  The next 6-month sponsor meeting is being planned for August of 2008, and a Track Symposium that will be open to non-sponsor participation is being planned for February of 2009.  Many reports on Track research have been published and are available for download.