What is Pervious Concrete?
Pervious concrete is a porous concrete paving material which permits rain and storm water runoff to percolate through it rather than flood surrounding areas or storm drains. It acts as a filter to trap and remove pollutants from rain run-off. This allows the sun’s heat to evaporate volatiles leaving the remaining solids to be consumed by microbial action.
It is usually a mixture of 3/8″ to 1/2″ average diameter aggregate (although sometimes larger aggregate, especially granite may be used), hydraulic cement, other cementitious materials, admixtures and water. When properly placed, pervious slabs will contain voids that would be normally filled by sand. Like a honeycomb these voids are held together with cement paste. These irregular voids by compaction add great strength to the slab. Our propriety designed pervious mixtures are the result of over 30 years of experience. When cured it resembles popcorn slabs.
Pervious Concrete (PC) is not to be confused with Roller Compacted Concrete (RCC). Roller Compacted Concrete is an Impervious Concrete pavement using recycled concrete, local aggregates, Portland cement and water. RCC prevents storm water from reaching the aquifer.
Though it is available from many concrete plants, our engineered mixture is only one key ingredient to a porous paving system.
Pervious Concrete’s void structure not only provides pollutant capture, but with proper compaction adds significant structural strength as well. Moisture captured by capillary action in the top inches of the slab reduces ambient temperature through evaporation and reflection of sunlight. The solar reflective index (SRI) averages about 29. By comparison asphalt has a SRI of 0 to 6 depending on its age.