Long-Term Performance of Cold In-Place Recycled (CIR) and Full-Depth Reclaimed (FDR) Base Layers in Minnesota State Roads, Phase ll

Status:  Active
Project Start Date:  No Date


The project will investigate, document, and demonstrate engineering lessons from MnDOT’s use of reclaimed (CIR, FDR, or SFDR) base layers in asphalt-paved state roads on a road-by-road basis (or cluster of roads). In September 2017, MnDOT rehabilitated approximately 20 miles of Minnesota Highway 19. The rehabilitation included a cold in-place recycled (CIR) layer over an existing concrete layer to produce a road structure that MnDOT refers to as a bituminous over concrete (BOC) pavement. Immediately after the Highway 19 rehabilitation, MnDOT initiated a 4-year research project to monitor the performance of the BOC road section. As the BOC-monitoring project approached its close in Summer 2021, MnDOT staff observed that the project provided a resource that MnDOT does not typically have: regular performance considerations of roads using novel engineering techniques and materials (such as BOC). This prompted the question, “What if we monitored other in-service roads this way and/or documented the performance of state roads using CIR or full-depth reclamation (FDR) techniques?” The contract work was paused to consider ways to answer the question and extend the project activities beyond Highway 19. This second research initiative then was proposed.

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