Pervious materials experts have sought out ways to improve the materials durability in order to add to its long list of benefits for the owners and architects to specify it. Laboratory research and real-world projects have shown that synthetic fibers can answer these sought after durability goals, by reducing surface raveling and abrasion, increasing the freeze/thaw resistance, and improving the overall toughness of pervious concrete pavements. As an integral, non-corrosive, three-dimensional reinforcement method, synthetic fibers represent the best opportunity to enhance the performance of pervious concrete and allow its use with confidence in future applications.
How It Works
In pervious concrete, carefully controlled amounts of water and cementitious materials are used to create a paste that forms a thick coating around aggregate particles (perviouspavemnet.org). A pervious concrete mixture contains little or no sand, creating a substantial void content. Using sufficient paste to coat and bind the aggregate particles together creates a system of highly permeable, interconnected voids that drains quickly (perviouspavemnet.org). Both the low mortar content and high porosity also reduce strength compared to conventional concrete mixtures, which can be addressed with synthetic fiber reinforcement. Synthetic fibers can be easily added into the pervious mix, resulting in an easy to use mix that is both durable and long lasting.
FORTA Products for FRP Applications
GREEN-NET® is made from 100% recycled polypropylene and is used to reduce plastic and hardened concrete shrinkage, settlement cracking, improved impact strength, increase fatigue resistance and concrete toughness. This heavy-duty fiber offers long-term durability and true secondary/temperature control by incorporating a fibrillated pattern and long length option.
FERRO-GREEN® blend consists of 100% recycled polypropylene fibrillated (network) fibers and a high-performance twisted-bundle macro-monofilament fiber, designed to mix, distribute, and finish well in pervious concrete mixes. This fiber combination offers a variety of desirable benefits to pervious concrete pavement applications, including increased strength, toughness, freeze-thaw resistance, and durability.
FORTA Fiber Reinforced Pervious Project
For the new Commuter Park & Ride facility in Newnan, GA, the Georgia Regional Transit Authority (GRTA) chose pervious concrete as an eco-friendly material to help manage storm water issues on their large parking lot site. To provide early stability and additional toughness to the pervious matrix, consultant Dale Fisher specified a synthetic fiber reinforcement that would not rust or break down over time
In all, the fiber-reinforced pervious concrete was used in over 30,000 sq. ft. of car-park lot and has performed well in this high traffic GRTA facility that services the Newnan-to-downtown Atlanta commuter route. This popular Route # 450 cycles 13 times daily, and is part of this State of Georgia authority’s effort to improve regional mobility, air quality, and land use practices. The GRTA mission is to reduce ozone and particulate matter levels in the air and help metro counties meet local air quality standards and sustainability requirements. As evidenced in the project photographs, the pervious pavement successfully drains surface-available storm water, while the surrounding asphalt pavement retains rainwater.
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