CTR Models in Use in the Netherlands
The Highway Administration of the Netherlands is using CTR research to help manage its pavements. As almost all roadways in The Netherlands are surfaced with single-layer or double-layer porous asphalt, the interaction of surface and subsurface drainage is an essential factor to consider, particularly given the country’s history with flooding. As the Highway Administration was updating its Motorway Design Guide, a representative contacted Dr. Randall Charbeneau in late 2015 for information about two projects he was involved in. Both these projects used numerical models in assessing the topics at hand: water ponding in superelevation transitions and water flow in permeable friction course.
Superelevation transitions are used to help balance centrifugal forces on vehicles moving through curved highway sections. These transition areas create longer drainage paths for stormwater runoff and increase ponding on roadway surfaces. Results from TxDOT Project 0-4875, Minimum Longitudinal Grade at Zero Cross Slope in Superelevation Transition, are helpful in identifying locations where enhanced drainage treatments may be useful in offsetting the effects of superelevation transitions. Both a rainfall simulator and a roadway model were constructed to investigate the behavior of sheets of water on rough impervious surfaces during storm events.
Permeable friction course is an overlay of porous asphalt placed in a 2-inch layer on top of regular impermeable pavement. Rain water enters the porous layer and gravity helpfully directs it to the side of the road, improving visibility and reducing splash and spray. Results from TxDOT Project 0-5220, Investigation of Stormwater Quality Improvements Utilizing Permeable Pavement and/or the Porous Friction Course (PFC), had several direct and immediate implications for the state of Texas, and indeed any area in the world that uses this paving method.
The 0-5220 project team at CTR affiliate Center for Research in Water Resources (CRWR) was specifically using a model called Perfcode (short for Permeable Friction Course Drainage Code). The Highway Administration representative, Jacob Groenendijk, noted that “It would be of great help to us if we could use this model ourselves,” and asked for access. CRWR alum Brad Eck, who developed the model for his doctoral thesis and is now a scientist at IBM Research in Dublin, provided the link to Perfcode’s location on GitHub. Dr. Groenendijk installed the software and, after some successful trial runs, transferred the files to the Dutch Ministry of Infrastructure for use in their operations.
Read the reports:
- Highway Drainage at Superelevation Transitions (2008) by Randall J. Charbeneau, Jaehak Jeong, and Michael E. Barrett: Read the full technical report (0-4875-1) or the two-page project summary report (0-4875-S).
- Investigation of Stormwater Quality Improvements Utilizing Permeable Friction Course (PFC) (2010) by Bradley J. Eck, J. Brandon Klenzendorf, Randall J. Charbeneau, Michael E. Barrett: Read the full technical report (0-5220-2) or the two-page project summary report (0-5220-S). See also this project’s first report: State of the Practice: Permeable Friction Courses (0-5220-1).