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Could garbage hold the key to carbon-friendly concrete?

Ian Harvey
Could garbage hold the key to carbon-friendly concrete?

Combining two disparate technologies could create greener concrete and resolve the pressing environmental issue of waste management.

It’s early days for both, but the concept of adding graphene — a rare earth material 200 times stronger than steel and 100 times stronger than diamond — to concrete mixes has proven to create stronger, lighter structures, which require less or no rebar, while consuming less cement and aggregate.

The big issue is cost.

Graphene is expensive compared to other additives even though proponents say that the initial expense is offset through the use of less material and labour, ease of use and resistance to water permeation.

That’s why the work by researchers at Rice University in Houston to develop and patent a process to zap waste and extract graphene is promising and could unlock the potential of graphene concrete.

They have leased space at Xerox’s Research Centre of Canada in Mississauga, Ont., says Dru Kefalos, chief marketing officer at Universal Matter, the company spun off from the work at Rice University. They’re looking to get an industrial process going within 18 months.

Graphene was only isolated in 2002. Since then interest has exploded because it has a myriad of uses, from electronics, to batteries, to solving the chfmiallenge of wind and solar energy production. Now concrete is part of that growing list of hundreds of applications.

Ontario is also in the race to produce graphene with the reactivation of the Kearney mine and mill near Algonquin Park which sits on the largest graphite resource outside of China and North Korea.

It closed in 1994 when world graphite prices dropped but the lure of graphene — extracted from that mineral — has spurred new interest and investment in the 445-acre Crown land site.

 

You increase strength by say 100 per cent but reduce mass by 50 per cent,

— Roger Foster

CenoStar

 

Zen Graphene Solutions is also getting funding to develop graphene concrete in collaboration with the University of Toronto and the University of British Columbia to extract and process graphite from its Thunder Bay property.

Graphite is a precursor to graphene and with more supply in a variety of forms each suitable for specific applications prices are dropping.

The breakthrough needed, both those on the graphene production side and the concrete additive side say, is for a client to commission the graphene concrete for a major project to showcase its value and benefits.

“CenoStar has been in the additives and concrete business for 25 years but this is by far the most exciting opportunity I have seen,” says CenoStar CEO Roger Foster, but it’s not an easy sell despite his faith.

Oil companies are looking at it for wells, he says, because they demand high performance and a clean environmental slate.

“Really it astounds me that the benefits are you increase strength by say 100 per cent but reduce mass by 50 per cent,” he says. “But it comes down to ‘show me’ ”

Still, he says, the benefits for application in deep sea rigs is palpable.

“No one wants another Deepwater Horizon (the BP rig which exploded in April 2010) and that was caused by faulty concrete.”

Dimitar Dimov, whose 2014 work at Exeter University in Britain led to a patented formula for graphene concrete, has since founded and is CEO of U.K.-based Concrene which is seeking to market it.

“I was doing pure research with no pressures to develop a product for business,” he says, recalling the discovery that graphene, in the right sized particles would bond inside concrete and had cementous properties of its own. Not only that, the final product had better performance characteristics in terms of flexibility and compressive strength.

“And it was non-porous,” he says, an important factor in concrete lifecycle since it’s ultimately another benefit to offset the higher initial cost and especially relevant in Canada where the climate of freeze and thaw is highly destructive.

“Graphene comes in all shapes and forms and is being commoditized but not all graphene is suitable for concrete,” he notes.

The first challenge is end of lifecycle, he says, with nanoparticle in graphene powder — between one and 10 layers of the atomic structure — used in concrete turning to a toxic dust when the structure is demolished or starts to crumble which creates a health and safety issue, much like asbestos.

But fine particles are more expensive while the coarser graphene, some 25 layers instead of 10 atomic layers, is perfect for concrete and its price is dropping.

After trying to interest the Ready-Mix market, he’s now switched focus to the precast market where he thinks graphene concrete’s lighter qualities, yet strength, will win over interest.

“You can transport more panels per day, install more precast and the higher productivity will also offset costs, though, of course, you’re using less concrete and no rebar which also saves labour costs,” he says.

While graphene has been selling for up to US$3,000 a pound, he says the reality is the price as been dropping as more sources come on line.

Also, he says, the larger particles cost less, around US$150 a kilogram, but again it’s been a tough sell.

Still, he says, the advantages are found in many bespoke applications such as marine concrete, or bridge foundations because of its impermeability while roads are another promising destination.

“We’re trying to meet now with developers because they will opt for something which gives them an edge in the market,” he says.

He hopes that promising a lower carbon footprint on a project may create a marketing edge for those solicited LEED points.

“Right now, it’s a bit of a stand off between us and the industry.”

Meanwhile, anticipating that Dimov and Foster and others are successful in getting construction sector buy in, Universal Matter is busy ramping up to move from the laboratory bench to commercial production and their horizon is surprisingly ambitious.

“We hired four scientists to get started in Texas,” Kefalos says. “And now we have nine and hiring three in Mississauga.”

Further, says Kefalos, the source material for the process can be any kind of waste, plastic or organic such as food, tires or plastic.

“It works really well with coffee grounds so maybe we should give Tim Horton’s a call,” he joked.

Recent Comments (1 comments)

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Nicholas Wolynsky Image Nicholas Wolynsky

Fascinating article. I hope this is 2-3-5 years away. Sounds promising.

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