Pervious concrete is a special type of concrete with a high porosity that allows water from precipitation and other sources to pass directly through.
Porous asphalt is standard hot-mix asphalt that allows water to drain through it.
Permeable interlocking pavers consist of concrete or stone units with open, permeable spaces between the units.
The most commonly used permeable pavement surfaces are pervious concrete, porous asphalt and permeable interlocking pavers. Examples of these three variants of permeable pavement are illustrated in Photos 1, 2 and 3.
Other variants not discussed in the articles on permeable pavement include single-sized aggregate, porous turf, permeable clay brick pavements, resin bound paving, and bound recycled glass porous pavement.
To assist with selection of the type of surface, a general comparison of the properties of the three major permeable pavement types is provided in Table 1. Designers should check with product vendors and the local review authority to determine specific requirements and capabilities of each system. Schematic cross sections of each system are illustrated in the design section for permeable pavement.
Properties of permeable pavements