Pervious Concrete has a greater void content in contrast to regular concrete which is achieved by manipulating the water and cementitious material ratio to essentially produce a void around aggregate particles. The product is a result of little or no sand that enhances the void content upto 25% consequently allowing water to drain through it at a rate of 5 gal/ft²/ min or 200 L/m²/min. Previous Concrete reduces chances of flash floods and is inline with rain water harvesting methodologies as it strives to capture storm water and allow it percolate into the ground thereby boosting groundwater recharge simultaneously easing the demand on storm water runoff control structures
Pervious Concrete areas have proven to be so successful that EPA has recommended use of Pervious Concrete as a Best Management Practice (BMP) for storm water runoffs. Use of Pervious Concrete also minimizes land use for otherwise storm water runoff control structures such as detention or retention basins.
Certain governing bodies mandate first flush (1-inch/25mm) pre-treatment before its subsequent release to the environment. Studies show a considerable pollution reduction (TSS, TP, TN and metals) achieved by natural degradation. To encourage this relatively new find, U.S. Green Building Council’s Leadership in Energy & Environmental Design (LEED) Green Building Rating System (Sustainable Sites Credit 6.1) considers allotting a credit point due to its potential of controlling stormwater runoff and pollution prevention. The lighter color of this concrete has an added advantage of absorbing less heat and storing even smaller portion of it owing to its porous structure.
Although initial costs of installing Pervious Concrete pavements is higher, it proves economical and is widely recognized as the lowest life-cycle cost option available for paving because:
- · Superior durability and strength
- · Fewer repairs
- · Minimizes need of runoff retainers leading to lower property costs
- · Little overproduction as its made on-site
- · Can be recycled at the end of its life-cycle.