Porous Pave replaces tree grates
GRAND RAPIDS, Mich. — In its continuing effort to make its downtown more welcoming, and to support its sustainability initiatives, Grand Rapids is completing the replacement of 750 old iron tree grates with Porous Pave XL. Porous Pave is a highly porous, durable and flexible pour-in-place surfacing material that is a proven solution for green stormwater infrastructure. An eco-friendly green building product, it consists of recycled rubber, stone aggregate and a binder.
The first phase of the project was completed in September 2014 before the annual ArtPrize event. The city had Porous Pave tree surrounds installed to replace 250 cracked and broken grates that presented the most serious tripping hazard in the three square miles of downtown. An additional 500 grates will be replaced by July 2015.
“Porous Pave allows rainwater and air to get down to the tree roots,” said Mark DeClercq, P.E., city engineer. “With its high rubber content and textured surface, Porous Pave is slip resistant and safer when wet than traditional metal tree grates.”
“Porous Pave is ADA-compliant,” said Dave Ouwinga, president and chief executive officer, Porous Pave. “In addition to making Porous Pave surfaces slip-resistant, the recycled rubber gives it flexibility, so it withstands freeze-thaw cycles without heaving, cracking or breaking.”
Made in the U.S.A., Porous Pave XL is a hard, durable material made from 50 percent recycled rubber chips and 50 percent stone aggregate with a moisture-cured urethane binding agent. Porous Pave infiltrates stormwater on site, decreases the volume and slows the velocity of runoff flowing into storm drains and storm sewers, improves water quality by reducing erosion and filtering out pollutants, and recharges groundwater. Porous Pave is engineered with 29 percent void space. Independent testing confirms that Porous Pave allows up to 6,300 gallons of water per hour per square foot to drain directly through its surface, permeate down into a compacted aggregate base, and then slowly filter into the ground
Porous Pave is poured in place at thicknesses of one to two inches atop a compacted aggregate base of two, four or six inches, depending on the application and required compressive strength. Contractors use it in public, commercial and residential installations for loading docks, parking lots, driveways, building entryways and courtyards, walkways and sidewalks and patios and terraces. The material's porosity, permeability and slip resistance make it ideal for tree surrounds.