Modulus Mapping of MnROAD Pavement Foundation Layers

Several test sections at the MnROAD pavement research facility in Minnesota were reconstructed in summer 2022. Roller modulus mapping was performed to assess foundation layer support conditions, with independent calibration using in situ cyclic plate load tests, and the results are compared with the assumed design values. A new approach was implemented to develop field target values that linked 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. e-Compaction reports were generated for the modulus mapping runs in near real-time to proactively address poor support conditions. Spatial maps of resilient modulus and "blob" analysis maps showing contiguous poor support were generated to improve performance ranking of current experiments. The mapping results identified low modulus areas and allowed for analysis of variability, differences in support conditions between the sections, and between passing and driving lanes.