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The 2022 construction season at the MnROAD facility saw construction of 39 new and unique pavement test sections and the repairs of 6 existing test sections. These sections were planned and designed by the National Road Research Alliance (NRRA) teams to address high-priority research needs. This report details development, design, and construction of each test section supporting the associated research studies developed by the teams. Individual study details are left to future reports generated by the individual research contracts and their respective NRRA teams. As a multi-state, pooled-fund program, the National Road Research Alliance (NRRA) provides strategic implementation of pavement engineering solutions through cooperative research. For Phase II, NRRA focused on improving sustainability and resiliency of our national pavement system and studying and promoting intelligent construction technologies. Based on these goals, some test sections were rehabilitated to extend their life by recycling in-situ material and applying preventive maintenance techniques. Newly constructed tests sections used innovative materials such as plastic, rubber and fibers for asphalt pavements and alternative cementitious, alternative supplementary cementitious, and carbon injection for concrete pavements. Two test sections served perpetual pavement and wicking geotextile research projects. Both were designed and constructed as perpetual pavements one of them with a wicking geotextile on top of the subgrade for improving drainage and stiffness of road foundation and quantifying its long-term benefits. Six test sections were repaired using performance engineered mixes on the replacement panels and finished with diamond grinding to eliminate faulting.

The Minnesota Department of Transportation (MnDOT) investigated the use of dowels with various anchoring methods and their effects on pavement performance. In a previous study, the characteristics of various epoxy and grout anchorage systems at the interface between new construction and existing concrete were studied using cut-out slabs brought into the Minnesota Road Research Facility (MnROAD). This investigation seeks to validate the findings of that study. Twelve different anchoring materials and methods were studied and compared to a control using no grout. This study did not examine the effects of a reduced number of dowels across a lane but rather looked at only the anchorage materials and methods. This experiment was performed on westbound lanes of Interstate 94, adjacent to the MnROAD test track. The field experimentation and monitoring involved core samples and measured ride quality, International Roughness Index (IRI), and Falling Weight Deflectometer (FWD) load transfer and fault measurement. These results supplemented the findings from the previous in-house performance categorization experiment. The control experiment, conducted without any grout or epoxy, initially displayed a notably low Load Transfer Efficiency (LTE). However, over time, there was a gradual improvement, leading to a more consistent LTE, attributed to the deployment of non-mechanical load transfer. Based on the slab thickness, the 1.25-inch dowel did not indicate any statistically significant LTE or other performance improvements over the 1-inch dowel within the anchorage types examined. Overall, the Epoxy Experimental 1 performed best while the un-grouted and unrepaired cells had the lowest performance. Moreover, no material clearly indicated characteristically low performance.

The Minnesota Department of Transportation (MnDOT) recognizes the importance of subsurface drainage in pavements. Various studies have indicated that adequate drainage of pavement layers enhances performance of pavements in general. MnDOT thus uses various types of subsurface drainage in varying degrees of styles, frequency of use, and minor variation in construction practices in the various transportation districts of the state. The subsurface drainage technologies include Open Graded Aggregate Base (OGAB), Drainable Stable Base (DSB), Permeable Asphalt Stabilized Base (PASB), Geocomposite Joint Drain (GJD) and Class 5Q aggregate. This study examines the various drainable bases in the network and identifies their locations and limits. Using performance data from the pavement management system, the performance, measured via Ride Quality Index (RQI), of test sections with drainable base systems was compared to contiguous sections without the systems so that traffic and environmental factors as well as other variables were held constant. Reliability and logistic analysis were conducted to ascertain if there were performance advantages in the drainable systems. The difference between the systems was found to be advantageous in certain districts, and an operations research survey reflected advantages in the drainable systems where and when they were associated with proficiency in construction practice.

The Minnesota Department of Transportation (MnDOT) investigated the use of dowel bars with various anchoring methods. This report examines the characteristics of various epoxy and grout anchorage systems at the interface between new construction and existing concrete. Twelve different anchoring materials as well as various anchoring methods were studied and compared to a control using no grout. This study did not examine the effects of the number of dowels used but instead was limited to the methods and materials used to anchor the dowels. This experiment was performed on concrete panels in-house. The tube grout method exhibited the best visual and magnetic imaging results. The evaluation methods did not clearly categorize the materials in order of performance but showed advantages of cleaning the drill-hole prior to dowel placement as well as the merits and demerits of using a retaining collar. The results generally suggested the need for an actual deployment research project on actual pavement in real-world service conditions. The field experiment was reported in a separate document.