Stabilization Procedures to Mitigate Edge Rutting for Granular Shoulders, Phase II (TR-591)

Project status


Start date: 04/01/08
End date: 05/31/11


Principal investigators:

Co-principal investigators:

Student researchers:

  • Peter Becker
  • Chase Westercamp
  • Thang Phan

About the research

Edge ruts can quickly develop in certain critical locations causing severe safety problems that require managers to quickly redirect resources away from routine maintenance tasks and compromising efficiency. Therefore, this issue can disrupt the entire workflow for a maintenance group with ripple effects that could result in situations where seemingly unrelated maintenance issues receive less attention than they should.

A multifaceted investigation was undertaken as part of this project to develop recommendations for methods to stabilize granular road shoulders with the goal of mitigating edge ruts. Included was reconnaissance of problematic shoulder locations, a laboratory study to develop a method to test for changes in granular material stability when stabilizing agents are used, and the construction of three sets of test sections under traffic at locations with problematic granular shoulders.


Report: Final Report: Stabilization Procedures to Mitigate Edge Rutting for Granular Shoulders - Phase II (26.93 mb pdf) May 2011

Tech transfer summary: Tech Transfer Summary: Stabilization Procedures to Mitigate Edge Rutting for Granular Shoulders: Phase II (3.29 mb pdf) May 2011



  • Iowa Department of Transportation
  • Reilly Construction Co.
Soft subgrade condition on shoulders
Soapstock stabilization 2000x
Compaction of fly ash stabilized shoulder
Shoulder edge rutting
Cement stabilization of shoulders