Innovation is the lifeblood of construction and as the industry’s needs have changed so have the means, methods, and materials used to solve challenges. Designers, engineers, and builders search for sustainable solutions to age-old considerations. Yet sometimes there is no substi- tute for tried and true, proven performance. When it comes to perme- able paving systems, there is one proven product that is hard to beat. Used on projects around the country, Grasscrete offers a solid, drivable surface that can be planted with grasses or other vegetation to become completely and naturally concealed. Spanning 1,300 acres, Orange County Great Park is a former Marine Corps Air Station in Irvine, California readapted to be one of the larg- est parks in the world. Meeting California’s landscaping water conser- vation requirements on that size property while creating the necessary vehicular accessibility was no small order. The requirements include establishing a maximum amount of supplemental site irrigation and encouraging 100 percent of groundwater capture and retention onsite. Florasource, Ltd. a California horticultural supply firm supported the buildout with a combination of materials ideally suited for the low- water climate and stormwater retention expectations. “We provided UC Verde Buffalograss and Grasscrete,” shares Flora- source founder, Tom Hawkins. “The grass is a great low-water lawn option that was bred specifically to grow well in drought-prone areas.” Requiring as little as 25 percent of the water of traditional turf grasses, UC Verde Buffalograss peaks at a growth height of just six inches. On the hardscape side, Grasscrete is a sustainable paving solution that was essential in meeting stormwater retention requirements. “Grasscrete is an incredibly durable, permeable paving product that al- lows grasses or other vegetation to be planted within it,” says Hawkins. Manufactured by Sustainable Paving Systems, Grasscrete is a concrete lattice of solid and void that combines the strength and rigidity of a single, structural framework while providing access to soil, water, and sunlight to sustain vegetation. The result is a planted permeable surface that remains drivable when needed. In Irvine, Grasscrete was used to create hard, drivable surfaces for utility access roads, emergency ve- hicle fire lanes, and shoulders for roundabouts in bordering neighborhoods. The key to Grasscrete’s durability is the molded pulp former. This third-generation product allows cast-in-place concrete to be continu- ously reinforced with #4 rebar. Grasscrete's compressive strength is identical to other concrete flatwork, ranging from 45 psi to 6,000 psi depending on the specific mix. An important part of concrete’s strength Here, There, and Anywhere wherever a drivable, vegetated surface is needed, Grasscrete is the answer By Sean O’Keefe
Lafitte Auditorium Grasscrete
is in the thickness of the slab; a minimum of 5.5 inches is recommended for Grasscrete. Like the Orange County Great Park, at the Dr. Martin Luther King Jr. National Memorial in Washington D.C. Grasscrete created a solid, vehicle-accessible walkway as part of a design-build delivery. Build- ers installed paved and plantable access over a 2,000-SF route to the back of an auxiliary building housing the Memorial’s Ranger Station, bookstore, and restrooms. A ramp between the sidewalk and street lets Park Rangers, maintenance vehicles, and deliveries come and go freely while limiting visitor disruptions. At the National Renewable Energy Laboratory (NREL) outside of Denver, Colorado, Grasscrete was incorporated in detention ponds to
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csengineermag.com
july 2020
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