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This report provides an integrated selection procedure for evaluating whether an existing hot-mix asphalt (HMA) pavement is an appropriate candidate for a bonded concrete overlay of asphalt (BCOA). The selection procedure includes (1) a desk review; (2) coring; (3) visual examination (site visit); (4) additional coring and/or laboratory testing (optional); (5) preparation of preliminary estimates (optional); and (6) a final report with design recommendations. This project also included an analysis of material testing performed by the Minnesota Department of Transportation (MnDOT) on numerous HMA cores to determine if the performance of existing BCOAs could be correlated to HMA material properties. The results of the laboratory testing were inconclusive. None of the existing HMA material properties tested could be correlated to long-term BCOA performance due to the high variability among the measured parameters within a section; the small number of cores per section; and the fact that the sections investigated exhibited little or no distress that could be attributed to the asphalt layer's properties. Although no conclusions could be made from the limited laboratory testing; it is fair to say that the BCOAs from these projects were performing as designed.

The use of roundabouts in rural areas of the US is growing rapidly. For roundabouts constructed with concrete pavement, joint layout can be especially challenging. To reduce the need for sophisticated joint layouts, consideration is being given to constructing roundabouts without joints and instead using structural fiber-reinforced concrete (FRC) to bridge any cracks that might occur. In 2018, Minnesota’s first jointless FRC pavement roundabout was constructed at the intersection of Minnesota Trunk Highway 4 and County State Aid Highway 29. The National Road Research Alliance (NRRA) sponsored a study to document the construction and performance of Minnesota’s first jointless FRC roundabout. One of the key objectives was to carry out a three-year performance monitoring regimen of the roundabout to better understand its in-situ performance when exposed to traffic loading and environmental conditions. This report documents the third-year performance of the roundabout as per the requirements of Task 3 of the work plan.

This document reports the activities and observations of a research team that performed on-site and laboratory testing of concrete mixtures with reduced cementitious materials content placed in two cells at the MnROAD facility in Albertville, Minnesota. The overall objectives of this research project included investigating the early age characteristics of concrete paving mixes containing reduced cementitious contents as well as their long-term performance. It was observed that while workability was marginal in the mixture proportioned with 470 lb/yd3, all other properties of the test sections were similar to those of the control section.