Minnesota Department of Transportation

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NRRA Rigid Team

Orange barrels on a highway

Design and Performance of Unbonded PCC Overlays

Status: Complete 

Project summary

Due to increased traffic congestion and reduced highway construction budgets, emphasis has been placed on seeking effective rehabilitation techniques for older pavements. Whitetopping and unbonded concrete overlays have great potential as pavement rehabilitation methods. Design thicknesses for these overlays tend to be greater than 7 inches. Due to the large initial cost of constructing these relatively thick layers (which includes costs associated with raising of the shoulders, bridges, and intersections), there is interest in understanding the performance of thinner unbonded concrete overlays.

NRRA is fortunate that MnROAD has constructed and instrumented thinner concrete unbonded overlays and whitetopping.

There is also interest in providing more information on types on interlayers for concrete overlays including new HMA, drainable coarse asphalt, milled/aged HMA, geotextile bond breaker. Guidance on what value these interlayers provide in the pavement design needs to also be explained.

Project tasks/status

Original Need Statement: Design and Performance of Concrete Unbonded Overlays (doc), August 8, 2016

Project Technical Advisory Panel (TAP) – email the TAP

  • Tim Andersen, MnDOT
  • Tom Burnham, MnDOT
  • Maria Masten, MnDOT
  • Charles Wienrank, Illinois DOT
  • Jim Wilde, MSU
  • Zhanping You, MTU

Final Report

Final published report (pdf), October 2020