Monday, October 7, 2013

Nycon-G uses recycled carpet for better, crack-free concrete

Everyone is familiar with the sight of steel “rebar” embedded in reinforced concrete, but you’d probably think twice about adding used carpet to concrete.

The use of fibers to improve building materials is a centuries-old technique. Animal hair was commonly used in plaster and mud bricks during the Middle Ages. Asbestos fiber was added to concrete during the early twentieth century. Fiber-reinforced concrete has better impact resistance and toughness than normal concrete, making it less likely to break into pieces.

Nycon pioneered the use of synthetic fibers, especially nylon, for reinforcing concrete during the 1980s. Both polypropylene and nylon fiber are especially good for preventing cracking in concrete. The fibers can stretch or shrink as the concrete around it contracts or expands, such as during temperature changes. Additionally, the fibers prevent any microscopic cracks that do form from growing into larger cracks.

Nycon found that the advantage of using nylon is that it’s stable in most conditions and stronger than polypropylene fibers. Nylon can be treated so the fibers’ surface bonds with concrete, allowing them to be mixed together with ease. Unlike polypropylene, nylon doesn’t float to the surface and is unnoticeable in the finished product.

The main disadvantage of using nylon is that it’s expensive– it costs almost twice as much per pound as polypropylene. Fortunately, there’s another source for nylon fiber: recycled carpet! The short fibers found in carpet are ideal for processing into fiber for improving concrete once removed from the backing and unbundled from the yarns. The multi-step process was developed and patented by Paul Bracegirdle and licensed to Nycon.

Nycon sells the processed, reclaimed carpet fibers as part of their Nycon-G product line, which typically sells for 20% less than its virgin-material counterpart. Testing has shown that there’s no difference in crack-prevention performance between Nycon-G and using virgin nylon (see a video of Nycon-G in action).

“Nycon-G has been fairly well accepted by the customers and used primarily due to lower cost than virgin,” says Paul Bracegirdle.

In addition to being less expensive, sourcing nylon from the carpet waste stream saves water, energy, and emissions while keeping valuable materials out of landfills!

The Heldrich Hotel and Conference Center in New Brunswick, New Jersey
relied on approximately 500 precast concrete panels that were
improved with Nycon-G.

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