Inverted Pavements – FHWA Task Order Request (TOR) # HIF200116PR (2020-2023)

Inverted Pavements – FHWA Task
Order Request (TOR) # HIF200116PR

The Client:
Federal Highway Administration (FHWA)

Our Work:

Inverted pavements is an innovative pavement design strategy that can result in economic savings and environmental benefits. As opposed to the traditional layering order of base layers, a stiffer treated base layer is placed on granular aggregate base layer.  The cement-treated subbase provides a stiff foundation for efficient compaction and constrains the deformation of the stress sensitive granular aggregate base. The thin AC surface layer deforms as a membrane resulting in low tensile stresses, hence better fatigue life. The construction of inverted pavements is a common practice in countries like Australia and South Africa, but the experience has been limited in the US. The objective of this project is to gather information about inverted pavements and develop a state-of-the-technology synthesis. Based on a worldwide review of the available information and existing projects in the US, the synthesis will document the current practice, usage, and performance of inverted pavements. At TEST, we are performing the following tasks:

  • Review of literature to include a worldwide review of current research/practice on strong pavement foundation applications and inverted pavements.
  • Compile data and information from five case studies documenting the use of inverted pavements in the US. Detailed information about each project, and any available performance records are collected to assess performance, sustainability, and cost-effectiveness of inverted pavements.
  • Develop a state-of-the-technology synthesis report for inverted pavements emphasizing the significance of strong foundations. The synthesis will present the available information on current practices in the design, construction techniques, maintenance (including preservation, repair, and rehabilitation), and other related technologies that would complement the implementation of inverted pavements in the US.
  • Present findings of the study through technical webinars and workshops in TRB and other venues.

The Outcome:
An interim report on the literature review and proposed case studies, a synthesis report presenting the findings of the study, series of webinars and workshop to present the synthesis report and case studies.