Carbon fiber waste used to improve water-draining concrete

Carbon fiber waste used to imp...
A sample of the carbon fiber-augmented material produced by the researchers
A sample of the carbon fiber-augmented material produced by the researchers
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A sample of the carbon fiber-augmented material produced by the researchers
A sample of the carbon fiber-augmented material produced by the researchers

Although the production of carbon fiber goods may be steadily increasing, recycling the material still remains challenging. Thanks to research being conducted at Washington State University, however, it may soon be possible to grind up carbon fiber waste and use it in new-and-improved pervious concrete.

First of all, what is pervious concrete? It's highly-porous concrete that stormwater run-off can drain straight through, passing into the soil underneath. Not only does it help prevent flooding, but it also reduces aquatic pollution – with traditional non-pervious concrete, the water runs the length of the road, accumulating more and more pollutants along the way, before going down a storm sewer and into the local waterways.

Unfortunately, though, because it's so porous, pervious concrete isn't as durable as its regular counterpart. That's where the carbon fiber comes in.

Led by Karl Englund and Somayeh Nassiri, a Washington State research team used an inexpensive mechanical milling technique to grind up scrap carbon fiber provided by Boeing. When that ground carbon fiber was added to the team's existing pervious concrete mix, the durability and strength of the resulting material was greatly increased.

"In terms of bending strength, we got really good results — as high as traditional concrete, and it still drains really quickly," says Nassiri.

Additionally, because the carbon fiber is left in its cured composite form, no heat or toxic chemicals are required in order to process it.

The scientists have demonstrated the effectiveness of the technology on laboratory samples, and now hope to conduct large-scale tests. A paper on the research was recently published in the Journal of Materials in Civil Engineering.

Source: Washington State University

Great! This is exactly what I want for my driveway. How fast can they roll it out?
What keeps the voids in the porous concrete from silting up over time? There is no information on the rest of the system. You would need an industrial vacuum cleaner, a porous substrate, geotextile filter and perforated conduit to carry away the water to be properly handled elsewhere.
Eugenio Caballo
I wouldn't choose this material nether for my driveway, nor for any road. Roads are not made perforated or porous for a good reason - the water filtering through would damage the supporting layers and it would result in a major collapse of the road. In colder climates the water inside the concrete structure would get frozen and break it after just a few freezing cycles. Still, although I suppose that the focus on the filtering roads made in the article is wrong, it could be used in many applications where uniform water filtering is called for, like e.g. in water treatment, drainage structures etc