Evaluating the Feasibility and Benefit on Impervious Layer Inclusion Above Ground Water Table (GWT)

Project No: 124060-RC00165

Target Completion Date: June 30, 2028

About the project:

The continuing increase in Sea Level Rise (SLR) results in elevated Ground Water Table (GWT), and whenever an elevated GWT is in the close proximity to subgrade, it softens the soil through enhanced moisture driven by the capillarity (i.e., upward movement of water from GWT). The moist and softened subgrade adversely affects the pavement construction and performance.

To this end, there is a need to perform a research/study to explore: (a) any existing correlation between SLR and rate of GWT rise to predict whether a project location is subjected to capillarity due to elevated GWT in future; and (b) identification of mitigation technique that is not limited to impervious layer in subgrade (that acts as a moisture barrier to hinder the capillarity from an elevated GWT), but also includes any effective local practice.

Expected Deliverables

  • An understanding of the correlation between SLR and rise in GWT for pavements located along coastal areas in Virginia.
  • Feasible mitigation technique that is not limited to inclusion of impervious layer, but also any local practice.
  • A guideline on when, where, and how to include impervious layer in subgrade (and any additional mitigation as identified), if determined as effective and economic mitigation option.


  • Perform Literature Review
  • Evaluating SLR and GWT in Virginia
  • Evaluating Feasibility (considering Constructability and Economy)
  • Development of Guideline

Project Team

Other Investigators

  • Dr. Burak F. Tanyu, George Mason University

Last updated: April 4, 2024

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