The trials in the US and Australia will test the potential of the Perth-based company’s carbon nanotube (CNT) technology to enrich the capabilities of building concrete.
It has for three years been developing applications for the super-strength micro-sized particles, including as an additive into plastics, but concrete looks like being the first product Eden will try to commercialise into an off-the-shelf product. Executive chairman Greg Solomon announced the strategy yesterday.
“Our forward strategy announced today is now to test our CNT-enriched concrete over the next 12-24 months in both the US and Australia, and prove up the markets before possibly licencing suitable admixture manufacturers to produce Eden’s admixture made with Eden’s CNT,” he said.
“Eden’s CNT enriched admixtures will be sold to concrete manufacturers or selected joint venture partners as the case may be and added into the concrete during production in the same manner that other admixtures are presently introduced to produce stronger concrete.”
Concrete is the most widely used man-made product in the world, the US alone consuming more than 700 million tonnes annually. Cement production is also a major source of greenhouse gases, accounting for 5% of annual global anthropogenic GHG.
“CNT-enriched concrete should significantly reduce the quantity of concrete required for structures and reduce or even perhaps eliminate the need for reinforcing steel, resulting in cheaper, lighter, stronger structures, far more flexible designs and far lower greenhouse gas footprints,” Solomon said.
The initial target market is high abrasion resistant applications such as road and bridge surfaces, followed by high rise applications, which for obvious reasons have more risk attached.
“In the United States alone, there are some 89,000km of concrete paved roads and bridges, with an annual US$40 billion maintenance bill, so nano-enriched concrete has a real value-add market opportunity to reduce these impacts while delivering a lighter, stronger material,” Solomon said.
Hythane Company, Eden’s wholly-owned US subsidiary, has commercialised a process developed with the University of Queensland to produce low cost CNT from natural gas, with the only products being hydrogen and CNT – and no CO2.
It has developed low cost reactors to produce about 40 tonnes per year of experimental nanotube batches, but Solomon says larger reactors will eventually be needed if the technology becomes established as a building “norm”. The modular system can be installed at gas-fired power stations or fertiliser plants and used to produce the CNT from the natural gas feedstock, while using the hydrogen by-product to produce cheaper electricity or the fertiliser.
The primary unresolved technical issue for the CNT-concrete application is to complete long-term tests to satisfy required standards and also to extend the shelf life of the admixture from 3 months to 6-12 months.
“Whilst the current shelf life is not considered to be a project stopping issue, it will require far tighter management of the distribution chain but we are confident that a suitable solution will be found,” Solomon said.
It has developed a process to mix its CNTs into cement paste, achieving an increased compressive strength of up to 30% using only 0.5% (by weight) of CNT and 99.5% by weight of cement, equivalent to only 600–900g of CNT per tonne of concrete mixtures. Solomon said 10,000 tonnes a year of CNT would be sufficient nanotubes for 17 million tonnes of concrete, or nearly 70% of the annual Australian concrete supply.
The carbon nanotubes are also highly conductive (thermal and electrical) and have a flexural strength 200-300 times stronger than steel. Solomon said current competitive concrete additives, such as high performance fibre reinforced concrete, fly-ash and blast furnace slag, increase the flexural strength of concrete but required significantly greater quantities of additives and finer crushed aggregates, and generally did not increase compressive strength – a factor necessary for abrasion resistance.
