The NCAT Pavement Test Track was originally constructed as a result of interest and support from state Departments of Transportation (DOTs) who shared a concern for reducing and predicting distresses in their flexible pavements. The cost for other states to sponsor the construction, testing, trucking and evaluation of experimental pavements was greatly reduced by a commitment from the Alabama Department of Transportation (ALDOT) to fund the original construction of the facility up to the top of the supporting pavement structure. The inaugural track was completed in the summer of 2000 and subjected to 10 million ESALs of heavy truck traffic through December of 2002. Built as a perpetual pavement, the first cycle of testing was a study of surface mix performance for forty-six 200 ft test sections. The facility was rebuilt in 2003, 2006, and 2009, with experimental pavements in each cycle subjected to 10 million ESALs of heavy truck traffic. Eight thinner structural pavements replaced the original perpetual pavements in 2003, increasing to nine in 2006, then sixteen in 2009, and finally nineteen in 2012, each instrumented for high-speed response to facilitate the study of mechanistic-empirical pavement design. The track will be rebuilt again in the summer of 2015, with many extended research options for potential sponsors, including MnROAD comparison sections.

The primary objectives of the pooled fund project described herein will be: 1. Constructing 200 ft test sections on the existing 1.7 mile NCAT test oval and MnRoad that are representative of in-service roadways on the open transportation infrastructure; 2. Applying accelerated performance truck traffic in the 2 years following construction; 3. Assessing/comparing the functional and structural field performance of trafficked sections on a regular basis via surface and subsurface measures; 4. Validating/calibrating new and existing M-E approaches to pavement analysis and design using pavement surface condition, pavement load response, precise traffic and environmental logging, and cumulative damage; 5. Determining the life cycle cost of various pavement preservation alternatives in a highly controlled experiment that will provide state DOTs with the financial foundation to begin to build a decision tree for their own maintenance program. These types of programs are then refined over time using actual pavement management performance data; 6. Correlating field results with laboratory data for both mechanistic and preservation applications. Laboratory performance data that can predict preservation outcomes would provide DOTs with an additional mechanism for making rational selection decisions; and 7. Answering practical questions posed by research sponsors through formal (i.e., reports and technical papers) and informal (e.g., one-on-one responses to sponsor inquiries) technology transfer. For example, can high RAP content mixes provide the same level of performance as virgin mixes? If so, can they be used in both deep and shallow layers? Although warm mix is better for the environment, will it provide the same level of rut and moisture damage resistance as conventional mixes?

The scope of work for the pooled fund project will include: 1. Hauling materials to the project from offsite locations. Material donations are typically secured by state sponsors, while reasonable hauling expenses are handled by the pooledfund; 2. Rebuilding sections in accordance with sponsors’ directives via competitively bid subcontracts administered by NCAT. It is anticipated that supply and grade control of subgrades and bases, aggregate hauling, liquid asphalt supply and delivery, plant production, and mix placement may all be procured via competitively bid subcontracts. Additional preservation treatment sections will be applied to a nearby low volume, high truck traffic roadway with distress conditions suitable for pavement preservation activities; 3. Installing both environmental (i.e., multi-depth pavement temperature probes) and response instrumentation (i.e., high speed stress and strain gages) in new experimental sections; 4. Operating a 5-truck heavy triple-trailer fleet in order to apply accelerated truck traffic following the completion of construction. Actual human drivers operate the vehicles in order to best induce representative vehicle wander; 5. Measuring field performance each week when the fleet is parked to fully document the changes in surface condition as a function of traffic and temperature. High-speed pavement response will also be measured on a weekly basis. Pavement deflection and surface friction will be measured on a monthly basis. Performance will be measured on off-Track pavement preservation sections on a monthly basis; 6. Conducting laboratory testing to quantify basic material and mix performance properties, which will serve as the basis of performance model development; and 7. Comparing predicted and measured pavement response as well as predicted and measured cumulative pavement damage in order to validate then calibrate prevailing M-E methodologies.

Each sponsor participating in the study is asked to contribute funding as a function of the scope of their selected research. The cost to participate varies as follows according to the amount of effort required: 1. Continue traffic on existing mill/inlay section = $80k/year ($240k/section) 2. Surface treatment on existing mill/inlay section (Note: Intended to provide access to project for private sector partners. It does not include the cost of materials, construction or mitigation. Commitment to rapid mitigation of failed experiments is required) = $80k/year ($240k/section) 3. Continue traffic on existing structural section = $100k/year ($300k/section) 4. Participate in the preservation group (PG15) study = $120k/year ($360k/sponsor) 5. Mill/inlay surface performance section = $150k/year ($450k/section) 6. Mill/inlay structural performance section = $180k/year ($540k/section) 7. Structural performance section (Note: This option also applies to participation in the Green Group (CG) study) = $210k/year ($630k/section) Funding requirements are based on reasonable assumptions; however, if project costs increase significantly (i.e., fuel) either a proportionate amount of additional funding or a modified scope of work may be required. Please visit the project web at www.pavetrack.com for additional information.