I added this to my actions when I was researching types of concrete and found Pervious concrete - I had heard of it a while back but never looked into it.
It creates a pavement that allows infiltration of rainwater rather than creating runoff. Because of the infiltration, ground water supplies are recharged and pollutants are treated.
Pervious concrete pavement is a pavement type that allows rainwater and other sources of water to percolate into the base layer below the concrete. Thus allowing the base material to absorb and control the flow rate of the water as it moves off site.
Pervious concrete's mass consists of an interconnected void structure, which allows water to flow through at very high rates. Typically, when cast on a sandy subgrade soil, the pavement will infiltrate stormwater at a higher rate than that of the soil below.
Structurally, pervious concrete is weaker than plain concrete and because of this, the product is not acceptable for building things. It is acceptable for light duty applications such as car parking facilities, pedestrian areas, and low traffic pavements.
It can be produced with a variety of coarse aggregates that result in many variations of concrete density. The key elements to pervious concrete pavements are the percent voids, permeability and compressive strength.
Uses/Applications
Pervious pavements are most often used for sidewalks and parking lots around residential and commercial
buildings. They are most beneficial when they increase the usable space on a project site as normally required retention ponds can be minimized or eliminated.
Product Benefits
Because of its porous structure, pervious pavement allows stormwater to percolate into the underlying soil while filtering out harmful sediments. This results in better stormwater quality, complying with new EPA regulations.
Pervious concrete pavement is a "green" product which can be laid next to trees and foliage, protecting root systems that may be beneath the paved areas. This pavement does not create hazardous runoff, nor does it prevent water from reaching roots.
Pervious pavement can double as a parking lot and retention area, maximizing the land that can be developed and lowering construction costs.