Located 50 miles east of Phoenix, Boyce Thompson Arboretum welcomes 85,000 visitors annually. From the Visitor Center, they walk downhill on the main trail to the Interpretive Center, picnic area, and on to the various gardens, exhibits, and natural areas. The trail down from the Visitor Center is the most public and heavily used. Its decomposed granite crushed stone eroded in heavy rains. Holes and washouts required frequent repairs. The Arboretum solved the problem by installing 2,980 square feet of Porous Pave XL. An eco-friendly, green building product made in the U.S.A., Porous Pave XL is a highly porous, durable, and flexible pour-in-place permeable paving material made from 50 percent recycled rubber chips and 50 percent stone aggregate with a moisture-cured, liquid binder.
“First impressions are critical. They can define the visitor’s experience. From the Visitor Center, what you’ll see first is a stunning vista,” says Mark Siegwarth, executive director, Boyce Thompson Arboretum. “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.”
“We don’t get a lot of rain in Arizona, but when it does rain, it pours,” says Julie Redfern, co-owner, AZ Porous Pave, regional distributor for the permeable paving product. “The crushed stone on the trail could not handle our short-duration, intense downpours. Critical parts of the main trail would quickly erode. Repeated repairs were disruptive, and all the patches made the surface uneven and unappealing.”
On the 857-square-foot section with the 20-degree slope, 2 inches of Porous Pave were installed on a new 3- to 4-inch aggregate base.
The Arboretum needed a pavement material that is strong and durable, safe and suitable for foot traffic and wheelchairs, slip-resistant when wet, low maintenance, and attractive. The answer was Porous Pave. 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, leaving no puddles on the trail. ADA-compliant, it is slip resistant and resilient because of the 50 percent recycled rubber content. Porous Pave colors are fade resistant. The manufacturing process infuses the rubber chips with dyes and UV inhibitors. The Arboretum selected the tan color to complement its landscape.
“One part of the trail has a 20-degree slope. Porous Pave is the only permeable paving option for steep slopes,” says Redfern. “The installation process is minimally disruptive, and the material cures in just 24 hours, so the surface is useable right away.”
“Porous Pave performs as promised. We have seen visitors walking with umbrellas in pouring rain, and there were no puddles, no erosion on the trail,” says Siegwarth. “One unexpected benefit is that the rubber imparts some give, making it comfortable to walk on. The material also catches the light. Depending on the light, there are subtle changes in its appearance, much like our natural desert landscapes.”
On the 857-square-foot section with the 20-degree slope, 2 inches of Porous Pave were installed on a new 3- to 4-inch aggregate base. 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. The installation was completed in May 2016.
Founded in 1924, Boyce Thompson Arboretum is the largest and oldest botanical garden in Arizona and one of the oldest botanical institutions in the West. An hour’s drive east of Phoenix and 3 miles west of Superior, the Arboretum is located in the Sonoran Desert on 392 acres beneath Picketpost Mountain and along Queen Creek. Its nature trails are a primary attraction. Walking along the trails, visitors discover cactus and demonstration gardens, palm and eucalyptus groves, and areas recreating various deserts of the world. The Arboretum is cooperatively managed by the non-profit 501(c)(3) Boyce Thompson Southwestern Arboretum, Inc., University of Arizona, and Arizona State Parks.
Porous Pave colors are fade resistant due to the manufacturing process that infuses the rubber chips with dyes and UV inhibitors; the Arboretum selected the tan color to complement its landscape.
Porous Pave, Inc. (Grant, Michigan) manufactures Porous Pave, a highly porous, durable, and flexible surfacing material consisting of recycled rubber, aggregate, and a binding agent. With 6,300 gallons per hour per square foot permeability, Porous Pave is a superior solution for stormwater retention. Every 1,000 square feet of 2-inch Porous Pave uses rubber recycled from 300 tires. A pour-in-place material, Porous Pave conforms to any landscape design and installs on grades up to 30 degrees. Porous Pave is easy to install. Using a standard mortar mixer, mixing time is under a minute. Curing time is only 24 hours.■
Got It On Video: Check out this article in the MCS July 2016 Digital Edition on www.mcsmag.com to see the installation in action.
For More Information:  For Porous Pave technical specifications, independent lab test results, and distributor locations, visit www.porouspaveinc.com.
Modern Contractor Solutions – July 2016
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