This new material is made of recycled tires, stone and a polyurethane binder
KBI, a UK-based company, has developed Flexi-Pave, a â€˜thirstyâ€™ concrete that can quickly absorb rainwater (just a square foot of the material can absorb 3,000 gallons per hour). The innovative product is 23% porous, as it is made of a fine-tuned combination of recycled tires, stone and a polyurethane binder invented by KBI, which gives the final product a flexibility that helps prevent cracking and tearing â€“ unlike epoxy resin bound systems. "Our most valuable resource is water," says Kevin Bagnall, founder and CEO of KBI. "If [Flexi-Pave] can be used in better urban planning, that valuable water is going to go back into the earth where it would naturally go, and therefore we'd be keeping the levels of our aquifer for potable water supplies." The disposal of used-tires in an eco-friendly way is also a great advantage of the method.
Apart from Flexi-Pave, there is also Topmix Permeable on the market, a similar product made by British building materials company Tarmac, which uses fines pieces of granite instead of recycled rubber and can absorb 880 gallons of water per minute according to the company. However, Bagnall believes that rubber is a superior choice to granite because it won't crack or settle, resulting to a more flexible final product.
Flexi-Pave in Yellowstone National Park
In 2016, a 4,000-square-foot walkway was built with Flexi-Pave inside Yellowstone National Park, in collaboration with the French tire manufacturer Michelin. According to Bagnall, the technology is especially useful for Yellowstone, whose geothermal system supports two-thirds of the world's geysers. Flexi-Pave's porous surface allows rainwater to shoot straight into the earth and its natural aquifers, instead of accumulating upon the parkâ€™s roadways and running off into rivers and streams. This way, the rainwater eventually replenishes the aquifers from which much of the water originally came. "We were the material of choice because of the zero environmental impact that we have," Bagnall says.
Flexi-Pave is already being used in 200 to 300 cities across the US, Bagnall says. But he hopes that his company will eventually expand to every major city around the world, as urbanization and population density both increase, and conserving clean water will become a much larger concern.
Â· Needs medium maintenance, only as required
Â· Removes significant amounts (up to 90%+) of soluble phosphates and nitrates.
Â· Resistant to freeze-thaw.
Â· Resistant to almost all chemicals.
Â· Installs 1", 1.5", or 2" thick.
Â· Starts at $10 per sq. ft
An image of the Flexi-Pave pathway laid out in Yellowstone.
Courtesy of Michelin