By now, many of you will have seen the animated .gif of a concrete truck pouring massive amounts of water on a concrete parking lot. The water appears to magically disappear into the parking surface, leaving many to wonder what the surface is made of and how it works.
The surface is pervious concrete and while it’s amazing stuff, it’s not quite magic. Pervious concrete is finding popularity from businesses and municipalities and approval from government entities like the EPA.
Pervious concrete, also known as porous, gap-graded, or enhanced porosity concrete, is concrete with reduced sand or fines and allows water to drain through it. Pervious concrete over an aggregate storage bed will reduce stormwater runoff volume, rate, and pollutants. The reduced fines leave stable air pockets in the concrete and a total void space of between 15 and 35 percent, with an average of 20 percent. The void space allows stormwater to flow through the concrete as shown in Figure 1, and enter a crushed stone aggregate bedding layer and base that supports the concrete while providing storage and runoff treatment. When properly constructed, pervious concrete is durable, low maintenance, and has a low life cycle cost. (water.epa.gov)
While pervious concrete is becoming popular, there are a few considerations to keep in mind. First, proper installation requires trained and experienced producers and construction contractors, like Pavement Constructors. The installation of pervious concrete differs from conventional concrete in several ways. The pervious concrete mix has low water content and will therefore harden rapidly. This requires quick set times, specific tools and equipment and different curing preparation and times.
Second, the load-bearing and infiltration capacity of the subgrade soil, the pervious concrete and the storage capacity of of the subbase must be engineered specifically for your ground composition and annual climate needs.
Third, there are some key siting and maintenance issues to keep in mind. Pervious concrete should not be installed where hazardous materials are loaded, unloaded or stored. Avoid areas with high sediment runoffs that may clog up the pervious nature of the concrete. Do not use sand for ice or snow treatment as it will cause similar issues to sediment runoff and lastly, periodic maintenance is recommended to keep pervious concrete flowing properly.
When considering new pavement options for your commercial or industrial paving needs, consider Pavement Constructors. We can help you discover the best solutions for your unique needs and provide you with a free estimate. Call us today at 281-445-9900 for your no-cost bid.