How does pervious concrete work?

Pervious concrete has functionality and workability similar to that of regular concrete. However, the pervious concrete mix lacks the sand and other fine particles found in regular concrete. This creates a significant amount of void space which allows water to flow relatively unobstructed through the concrete. Once through the concrete, the water flows into the infiltration bed beneath, which is filled with rock. The rock has a 40% void space allowing for the storage of the runoff until it is infiltrated into the soil. ... more