Sponsor – Alliance for the Chesapeake Bay
DC Department of Energy and Environment
1200 First Street NE 5th Flr
Washington, DC 20002
Grids are intended for limited traffic, i.e. less than 7,500 lifetime 18,000 lb. equivalent single axle loads or ESALs. They are constructed on a compacted aggregate road base. An inch of bedding sand is used to seat the units during compacted with a plate compactor. The openings are filled with topsoil and grass. The paving units can be hand or machine installed. Once in placed they are compacted, the openings filled with topsoil and grass seed. The surface is swept clean and compacted again. Several weeks should be allowed for the grass to grow. Regular watering is required until the grass is established.
Better grass longevity can be achieved by covering the grids with a few inches of topsoil and planting grass or installing sod. In places where grass cannot grow easily or be watered in dry periods, the grid openings should be filled with ASTM No. 8 stone or similar size material. Aggregate also should be used if sediment from the site or adjacent areas is expected to wash onto the grids or be deposited on them by vehicles. Grid installations require edge restraints to hold them in place. ICPI Tech Spec 8 – Concrete Grid Pavements provides edge restraint information and installation tips for a range of applications. The guide construction specification for concrete grids for installation on a compacted aggregate road base also appears at the end of the Tech Spec.
This cutaway installation show the grids and bedding sand on a compacted aggregate base.