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 building and preserving safe, sustainable, resilient, and cost-effective pavement infrastructure. Track research operations began in the summer of 2000. Forty-six 200-ft test sections were subjected to 10 million equivalent single axle loadings (ESALs) of heavy truck traffic through December of 2002. Test sections were rebuilt in 2003, 2006, 2009, 2012, 2015, and 2018 with 10 million ESALs applied within each 3-year research cycle. NCAT began formally partnering with the Minnesota Road Research Project (MnROAD) in 2015 to execute nationally relevant research in both mix performance testing and pavement preservation. Positive experiences with implementable findings that reduce the life cycle cost of flexible pavements and facilitate rapid deployment of sustainable technologies have made this research an outstanding investment for numerous state DOTs, who pool their resources to share the cost of construction, operations, and research in a cooperative manner. The summer 2021 rebuild is the starting point for the eighth research cycle, with many high reward research options available for potential sponsors. NCAT is again partnering with MnROAD in the 2021 research cycle to execute a pavement performance experiment with nationwide implementation impact.

The primary objectives of the pooled fund project described herein will be: 1. Constructing experimental pavements on the existing 1.7-mile NCAT test oval and the MnROAD mainline bypass that are representative of in-service roadways on the open transportation infrastructure; 2. Applying accelerated performance truck traffic after construction for the duration of the 3-year research cycle; 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 methodologies for analysis and design using pavement surface condition, pavement load response, precise traffic and environmental logging, and cumulative damage; 5. Correlating field results with laboratory data for both mix and structural performance; and 6. 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 pavement thickness be reduced as a result of the addition of premium mix additives, and if so does the thickness reduction offset the additional cost of construction?

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 pooled fund; 2. Rebuilding sections in accordance with sponsors’ directives via competitively bid subcontracts administered by NCAT. It is anticipated that aggregate hauling, liquid asphalt supply and delivery, rental of select construction equipment, plant production, and mix placement may all be procured via competitively bid subcontracts; 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 on the NCAT test oval following the completion of construction. Human drivers operate NCAT vehicles in order to best induce representative vehicle wander, but it is expected that autonomous vehicles will be implemented in the future. Interstate traffic is used to load test sections at MnROAD; 5. Safely measuring field performance (e.g., rutting, roughness, texture, cracking, deflection, friction, etc.) on a regular basis when traffic is suspended/bypassed to fully document changes in surface condition as a function of traffic and temperature. Highspeed pavement response will also be measured on a routine 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 analysis and design methodologies.

This project is expected to be eligible for 100% SP&R funding. 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: - Sections Utilizing “Non-Structural Continuation” Option (also surface treatments on existing sections) @ $83,333 per existing perpetual section per year for 3 years (FY 2021 - FY 2023) for a total of $250,000; - Sections Utilizing “Structural Continuation” Option (including high-speed response data collection) @ $100,000 per existing structural section per year for 3 years (FY 2021 - FY 2023) for a total of $300,000; - Sections Utilizing “Mill and Inlay for Surface Performance” Option @ $166,667 per new mill/inlay section per year for 3 years (FY 2021 - FY 2023) for a total of $500,000; and - Sections Utilizing “Structural Performance” Option (also applies to Additive Group (AG) Study) @ $250,000 per new structural section per year for 3 years (FY 2021 - FY 2023) for a total of $750,000. - Research for Environmental Product Declaration (EPD) and Life Cycle Assessment (LCA) Development Option that is complementary to the various technologies selected for inclusion in the AG study @ $120,000 in FY21. Funding requirements are based on reasonable assumptions; however, if project costs increase unexpectedly (e.g., fuel) either a proportionate amount of additional funding or a reduced scope of work may be required.