MnROAD Partnership

NCAT has partnered with MnROAD, a pavement test track owned and operated by the Minnesota Department of Transportation, for a parallel study in both northern and southern climates. NCAT and MnROAD are the nation’s two largest full-scale pavement testing facilities where using real construction methods and live trafficking under actual climate conditions provides an authentic environment for researchers to study and evaluate the performance of materials used in roadway construction. The primary research efforts in the partnership began in 2015 and focus on two important national issues: pavement preservation and cracking test validation.

Pavement Preservation Experiment

Many of the same pavement preservation treatments installed in Alabama are being investigated in Minnesota using MnDOT materials and construction methods. The northern pavement preservation experiment sections are located on U.S. Route 169, a high-volume road, and County State Aid Highway (CSAH) 8 in Mille Lacs County, a low-volume road. This study includes treatment selection, test site selection and layout, scheduling, construction, performance monitoring, and data activities to quantify the life-extending benefits of pavement preservation treatments. Additionally, a variety of cold recycle sections with thin overlay surfaces were installed on 70th Street just outside the entrance to MnROAD in 2019. 

Additive Group Experiment

Agencies are routinely approached by vendors who promote the use of premium mix additives. In many cases, it's claimed that the cost increase resulting from specifying a premium mix additive is more than offset by the ability to achieve equivalent performance from a thinner pavement structure. Independent, peer reviewed research is needed to validate these claims and build an objective framework to evaluate future premium mix additives. The Additive Group (AG) experiment is designed to meet this need. Relatively thin pavement structures have been built using an array of popular premium mix additives that includes recycle tire rubber, recycled plastic, and high strength fibers.  The measured service life of each structure under accelerated traffic using legally loaded axles is being compared to a conventional control structure.  Any treatment section that statistically outlasts the control section is a demonstration of improved structural performance. Additional traffic supported as a result of the premium mix additive can be used to assess return on investment. High-speed response instrumentation is being used to establish an ideal but practical laboratory characterization methodology and develop an objective and reliable framework to evaluate future premium mix additives. Test sections on the NCAT Pavement Test Track are being evaluated for fatigue cracking, while sections at MnROAD are being evaluated for thermal and reflective cracking.