Minnesota Department of Transportation

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Research & Innovation

Need statements

NS747: Design Guidance and Best Practices for the Use of Light Fill

Problem and objectives

Solid waste products have been successfully used in road construction as light weight fill (LWF), diverting them from ending up in landfills and recycling the waste material for beneficial use. There have been several past and ongoing studies (see list below). One specific product, Tire Derived Aggregates (TDAs) has been the target of study Updating MnDOT Guidance for Using Shredded Tires in Roadway Construction. This research will update and expand upon the work conducted in this study.

The focus of this project will be to review and synthesize all past and existing research, identify success stories and best practices of using LWF. This research will answer the following questions:

  • What products have previously been tested and evaluated?
  • Does LWF require special construction techniques?
  • Does LWF pose an environmental concern? Specifically, can they be used under the water table with no adverse effects?
  • What are the long-term impacts of using LWF? (trench settlement, e.g.)
  • How is LWF being utilized in other states?
  • Why do other states allow recycled rubber tire chips below the water table, but Minnesota does not?

To answer these questions, the research team will conduct the following:

  • Review and synthesize LWF best practices, including examples from outside of Minnesota.
  • Develop a matrix of LWF products/options and their uses.
  • Identify existing practices and evaluation, environmental concerns, special construction techniques, etc.
  • Conduct a survey of local agencies to identify success stories of LWF.
  • Develop report to understand the long-term (10+ years) effects on roadway conditions.
  • Develop reference materials for specific projects with project locations considerations, e.g., proximity to water, wetlands, etc.
  • If needed, conduct testing of recycled rubber tire used below the water to determine concerns of leachate (type and concentration).
  • Matrix for lightweight fill materials production options and uses.
  • Identified existing practices and evaluation, environmental concerns, special construction techniques, success stories, etc.
  • Report on results to understand long-term effects and road conditions.
  • Survey/poll results identifying potential success stories.
  • Reference material for specific projects with project location considerations, e.g., proximity to water, wetlands, etc.

Expected benefits

The numbers 1 and 2 indicate whether the source of the benefit measurement is from: 

  1. A specific research task in your project that supports measuring this particular benefit, or
  2. Implementation of the research findings (anticipating positive results)
  • Construction Saving; Expected savings from reusing materials (2)
  • Environmental Aspect: Reusing waste materials (2)

Previous research

Possible members for technical advisory panel

  • Justin Kannas, Buffalo City
  • JinYeene Neumann, Carlton County
  • Ben Worel, MnDOT OMRR
  • MPCA representative
  • Josh Bowe, Three Rivers Park District
  • Consider adding product manufacturers/suppliers within an Advisory/Working group