Minnesota Department of Transportation

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Road Research

NRRA Rigid Team

Concrete Overlays on Asphalt Containing Fibers Sourced from Recycled Materials


Two primary mechanisms of sustainability include the use of less resources and/or the use of recycled materials. Thin concrete overlays on asphalt (COA) require less materials than thicker overlays, but have some inherent challenges that must be dealt with to ensure long service life. These challenges include: (1) the relatively lightweight panels can be moved around much easier by heavy axles, (2) there is far less aggregate interlock available to transfer loads across transverse joints, and (3) it is difficult to incorporate standard load transfer devices into thin slabs. Many thin COA test sections have been studied at MnROAD, including ones with synthetic structural fibers, with the same result: development of substantial joint faulting. To ensure the continued use of thin COAs by agencies, it is important to continue to pursue new materials that address this issue.

The objective of this NRRA research project is to replace existing COA cells with new COA test sections toward two primary goals. The first goal is to continue to explore viable fiber types that can significantly arrest the development of joint faulting in thin COAs. The second goal is to provide an area to install the latest in Weigh-in-Motion (WIM) equipment that benefits the entire MnROAD mainline segment. Two new fiber-reinforced concrete (FRC) cells are proposed, utilizing fibers that can provide robust post-cracking residual strength and are currently (or potentially) constructed with recycled materials. One normal (non-fiber reinforced) concrete section with doweled joints is also proposed for installation of WIM equipment.

Project team

Principal Investigator: Tom Burnham, MnDOT, tom.burnham@state.mn.us
Technical Liaison: Joseph Podolsky, MnDOT, Joseph.Podolsky@state.mn.us
Project Technical Advisory Panel (TAP) - email the TAP
Contact us to join this TAP

  • Ali Arabzadeh, Wisconsin DOT
  • Manik Barman, University of Minnesota Duluth
  • Fatih Bektas, Minnesota State University
  • Jacob Gave, MnDOT
  • Qingxu “Bill” Jin, Michigan State University
  • S. David Lim, Caltrans
  • Joseph Podolsky, MnDOT (TL)
  • Dulce Rufino Feldman, Caltrans
  • Xijun "Jeff" Shi, Texas State University
  • James Wilde, Texas State University
  • Hao Yin, Horizon Engineering Consulting