HOTLINKS to download
PAVE reports, review
upcoming NCAT training courses, query historical w,
view current color radar or preview
on the Track as of 2300 hours on June 21, 2014 (82% of the 10,000,000
ESAL goal). Rut depths
averaged 5 mm, while roughness averaged 104 inches per mile.
this project via...
1600_Lee_Road_151 Opelika,_AL_36804_USA 334.844.7304
GOD BLESS AMERICA !
Aerial of 309 acre site (click here for
photo album, or click web camera to see all views)
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 plant-produced material 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 (firstname.lastname@example.org) or Buzz Powell (email@example.com) for additional information. The
fifth research cycle, for which the initial construction effort was completed in the
summer of 2012, is advertised on pooledfund.org.
The planning process is underway for the sixth (2015) research cycle, which
will again include research on pavement thickness design, mix
materials/methods, and pavement preservation. We appreciate your interest and value your feedback.
CONSTRUCTION - Reconstruction activities for the
2012 research cycle were completed in the summer of 2012. Draft quality control records
are available online on our construction
page. Test sections will be rebuilt for the sixth research cycle in the
spring and summer of 2015.
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
pavement testing (APT) because a design lifetime of truck damage (typically 10 to 15
years) is compressed into 2 years. Trucking operations began in the
fall of 2012 on October 23rd after the completion of construction, finish
work (e.g., shoulders, striping, marking, etc.), and baseline data
collection. 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 climate
controlled storage and used to fabricate specimens for many different types of laboratory
performance characterizations. 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, half of
the time is invested in classroom presentations and discussions, while the
other half is spent on the Track
inspecting test sections. The last 6-month sponsor meeting was held on
December 2nd and 3rd of 2013. The next 6-month sponsor meeting for the
2012 Track is being planned for May 14th and 15th of 2014. An
end-of-cycle Track Conference is being planned for March 3rd through 5th of
2015. Many reports on Track research have been published and are available for download.