Pervious Concrete Specifications

Environmental

• According to Concrete Parking Delivers, concrete pavement, including pervious concrete pavement, reduces the heat island effect up to 12 percent. Manmade structures cause the heat island effect because they attract and hold onto the heat. This increases ozone at ground level by nearly 30 percent and raises the temperature in the area -- perhaps by 10 degrees or more. Using pervious concrete improves air quality and helps reduce problems caused by extreme heat.

Water

• Pervious concrete allows water to pass through it because the concrete is not completely backed together. Small openings occur throughout the concrete, which catches the water and allows it to pass through these openings into the ground. According to the National Ready Mixed Concrete Association (NRMCA), pervious concrete has a void content between 15 and 25 percent, and the ratio of water to concrete is between 0.35 and 0.45. Pervious concrete is composed of cement, water and coarse aggregates. This composition allows between 3 and 8 gallons of water per minute per square foot to flow through the concrete, according to Concrete Parking Delivers.

Sidewalks/Pathways

• You can use pervious concrete to create sidewalks and pathways, especially since the color matches dirt paths more closely than asphalt and Tarmac. You can install pervious concrete near river and stream beds since the water runs through it. It also doesn't erode easily, and it withstands both extremely cold and warm temperatures.

Installation

• According to the NRMCA, you must properly compact your soil to ensure that the pervious concrete sets properly. The site recommends that you compact the sub-grade base to between 92 and 96 percent of the total, maximum material density. Wet down the sub-grade before installation, and rake out any construction traffic marks. Do not apply too much or too little water. Too much water causes the mixture to separate, and too little water causes it to cure improperly. In extremely cold climates, install the pervious concrete on an open graded stone base between 8 and 24 inches thick.