PERMEABLE SURFACE COVERING UNITS AND PERMEABLE SURFACE COVERING

摘要

A permeable surface covering unit comprises a top surface and at least two pairs of irregularly shaped mating sides, one or more passageways extending downwardly from the top surface, and at least one under channel connected to the passageways for retaining liquid, such as storm water. The sides of the unit preferably define an irregular rotational tessellation element. The passageways may comprise gaps or side cavities between units and/or core cavities or other passageways within the unit. Optional undercuts may be provided in the core cavities. Pervious material plugs are cast into the cavities extending into the channel or undercut. Thereby the plug is locked into the cavity like a rivet and resists being dislodged by mechanical or hydraulic forces. A permeable surface embodiment comprises a combination of pervious and impervious units, wherein the ratio of permeable to impermeable units and resulting surface absorption rate may be adjusted.