1373606 - Modulus Mapping of MnROAD Pavement Foundation Layers

MnROAD is a pavement research test track facility along Interstate 94 in Albertville, MN, owned and operated by the Minnesota Department of Transportation (MnDOT). MnROAD and its partners have performed strategic pavement research since the 1990s. In Summer 2022, several test sections (each about 500 ft long) along mainline I-94 were re-constructed to support research that focuses on sustainability and resilience, alternative materials, and intelligent construction technologies. The underlying foundation layers required assessment of support conditions across the different sections (unbound aggregate base layers and stabilized/bound materials). Roller modulus mapping was performed using advanced technology with independent calibration using in-situ cyclic plate load tests. Results are compared with the assumed design values per MnPAVE 2022 design software.

Further, results from the calibration analysis and a summary of the mapping results are presented. A new approach implemented on this project to develop field target values for assessing the modulus mapping results is also described. This approach links the design loading case with the in-situ cyclic plate load testing considering geomaterial stress-dependency, realistic stress-state conditions, and the measurement influence depth of the loading plate. Near real-time e-Compaction reports were generated for the modulus mapping runs to proactively address poor support conditions at the test track and to summarize key quality metrics. Spatial maps of resilient modulus values and “blob” analysis maps showing contiguous poor support areas larger than a defined size were generated to improve performance ranking of current experiments. The mapping results identified low modulus areas in the different sections and allowed for analysis of variability within each section, differences in support conditions between the different sections and between the passing and driving lanes.