Introduction to the Design of Pervious Concrete Pavement:

Properly designed and constructed pervious concrete pavements have been in service in the southeastern United States in excess of 30 years.  The keys to satisfactory performance include:

• Do not place the pavement directly abutting open, non-landscaped areas with loose soil.
  • Loose soil can plug the open voids, but the voids can be cleaned and the pavement restored to its original condition.
• A minimum soil percolation rate of 0.5 in/hr.
• The "drawdown" or time required for the pavement to regain its design storage capacity should be as quickly as possible but not exceed 5 days.
• The pavement's slope should ideally be in the range of 0% to 5%.  However, successful applications have been achieved, with special design considerations, in cases of 15% - 18% slope.

Pervious pavements are designed for the amount of water that can be captured and stored until drained into the subgrade (hydraulic) and for the traffic load (structural).  Examples of hydraulic design methods are the Los Angeles County Public Works BMP Handbook, Appendix and the North Carolina State University Hydraulic Design for Permeable Pavement.  The LA County procedure was developed for asphalt pavements, but has been adapted pervious concrete.  For a common set of initial criteria, both programs will yield similar pavement sections.

The structural section is designed using any standard portland cement concrete pavement design method.  Generally, the hydraulic section is thicker than the structural section.  In designing the structural section, the subgrade strength when fully saturated is utilized in the calculations.

See the documents below for more information.