Minnesota Department of Transportation

511 Travel Info

Road Research

NRRA Geotechnical Team

Orange barrels on a highway

Subgrade Design for New and Reconstructed

Project Start Date:
Project End Date:

Project Summary: Evaluate factors related to design, construction, and performance related to depth of subcuts, quality of backfill material, applications for subgrade preparation, and the use of geosynthetics for both concrete and HMA.   Consider existing MnDOT "frost-free" practices and alternate approaches including different type of granular subbase layers and geosynthetics under the top base materials. Design guidelines for a cost effective approach to design subgrades for both new and reconstructed roadways.

Project Tasks/Status:
Original Need Statement: Subgrade Design for New and Reconstructed - Draft March 2019 (WORD)

Task 1: Perform a literature search of existing information in regards to design of subgrades. This includes review of existing research projects and reports. This may also include current practices of state DOT’s and municipalities. Take into consideration “frost-free” practices, use of subgrade preparation, geosynthetics, granular subbase layers, and other alternative approaches.

Task 2: Develop guidelines for the design of subgrades at new roadway embankments and reconstructed pavement areas. Include field and laboratory testing required for proper design. Take into account aggregate availability, subsoil types, traffic conditions, and relative costs of using different approaches.

Task 3: Develop and conduct a webinar to present all findings

Task 4: Summarize all work/findings into a final report

Related Contracts/Tasks:
Note any other supporting contracts

Principal Investigator:  
Technical Liaison: 
Project Technical Advisory Committee (TAP)Email the TAP

Dan Wegman (Braun)
Terry Beaudry (MN)
Ed Johnson (MN)
Chris Dulian (MN)
Tim Andersen (MN)

Related Materials

Final Report: