ChrWeiss @ stock.adobe.com
Composed of a layer of permeable asphalt placed over a granular drainage layer that is on the top of a stone bed layer, porous pavement provides a higher amount of airflow in the paving surface, allowing it to be much more absorbent than regular asphalt. By creating an open-graded friction course, it allows rainwater to flow vertically into the soil, thus avoiding floods and accumulated water in traditional water-resistant surfaces.
Porous pavements are made of open-pore pavers, asphalt, or concrete, with a supporting stone reservoir. It allows rainwater to drain into a thin stone bed below while this traditional stage works as a filter. Subsequently, a third layer made of bigger stones works as runoff detention, where toxins that get infiltrated along with the rainwater pass through the stone bed and travel into a sub-base, where they are subjected to the natural cleaning water processes.