Porous Pave recently completed another sizable job, this one offering the company a chance to show that its flexible, pour-in-place permeable paving material can be applied just as effectively on steep inclines as it can on level surfaces.
The company installed 2,980 square feet of Porous Pave XL at the Boyce Thompson Arboretum about 50 miles east of Phoenix. The material is made from 50 percent recycled rubber chips and 50 percent stone aggregate, along with a moisture-cured, liquid binder.
The arboretum welcomes some 85,000 visitors annually who walk from the park’s visitor center downhill on the main trail to the interpretive center, picnic area and on to the various gardens, exhibits and natural areas. The sloping main trail was made of decomposed granite crushed stone and eroded in heavy rains, according to Porous Pave, with holes and washouts requiring frequent repairs.
The park chose Porous Pave to solve the problem.
“First impressions are critical,” said Mark Siegwarth, executive director of Boyce Thompson Arboretum. “They can define the visitor’s experience. From the visitor center, what you see first is a stunning vista. Visitors were taking in the view while standing on an unsightly crushed stone trail with patched holes and washouts. The condition of the trail detracted from the view.”
Julie Redfern, co-owner of AZ Porous Pave, regional distributor for the permeable paving product, noted that Arizona doesn’t get a lot of rain, “but when it does rain, it pours.” She said the crushed stone on the trail couldn’t stand up to the state’s short-duration, intense downpours.
“Critical parts of the main trail would quickly erode,” Redfern said. “Repeated repairs were disruptive, and all the patches made the surface uneven and unappealing.”
Moreover, the arboretum needed the trail to safely accommodate wheelchairs as well as foot traffic.
With up to 29 percent porosity, Porous Pave allows up to 6,300 gallons of stormwater per hour per square foot to drain through its surface. That means no puddles collect on the trail, Redfern says, and the material is also slip resistant and compliant with the Americans with Disabilities Act.
Porous Pave also boasts that its colors are fade resistant because the rubber chips are infused with dyes and UV inhibitors during the manufacturing process.
One part of the arboretum trail has a 20-degree slope. “Porous Pave is the only permeable paving option for steep slopes,” said Redfern. “The installation process is minimally disruptive, and the material cures in just 24 hours, so the surface is useable right away.”
On the 857-square-foot section with the 20-degree slope, 2 inches of Porous Pave were installed on a new base of 3-4-inch aggregate. On the other section of the trail, 2,126 square feet of Porous Pave were poured on the existing crushed stone after new aggregate was added in washout areas.
For more information about Porous Pave, visit the company’s website here.