Concrete gets cheaper, tougher and greener

The inventors of a cheap, low-carbon cement substitute battled for 20 years to reach commercial production. Aaron Morby finds out how RockTron won over the sceptics and kept its technology British.

Fly ash lagoon – RockTron raw feed

The biggest driver for construction in the next decade is likely to be the use of low-carbon technologies and delivering a sustainable built environment.

With this is mind, the Government is calling on the industry to take a lead in pioneering practical ways to cut carbon emissions. The stakes are high because UK construction is jostling for pole position with the US, China and the rest of Europe in the race to develop renewable energy sources and deliver the next generation of low-carbon buildings and infrastructure.

 

Support hard to come by

Yet the story of how two men faced an uphill struggle to win support for a new technique producing a low-carbon cement substitute offers a salutary lesson in the pitfalls of promoting sustainable products for the low-carbon era.

Their innovative process offers an elegant means of both cutting global carbon dioxide emissions and dispatching millions of tonnes of fly ash waste, yet it took two decades of grit and determination to find commercial backers to bring the process alive.

RockTron, the company founded by these men, has finally gone into production, purifying pulverised fuel ash into a superior cement additive that offers far greater performance than simple PFA.

 

Cheaper and tougher

From a strictly commercial standpoint, the tiny glass beads rescued from crushed fly ash are a perfect cement additive, promising to cut the cost of concrete by more than a third and reduce pre-cast strike times to just 14 hours. The minute beads also boast the property of strengthening concrete over time, and are particularly suited to marine environments.

On top of these benefits, tests show RockTron's product will substitute cement used for concrete by at least 50%. This is where the concrete industry has the opportunity to transform its green credentials by avoiding much of the carbon dioxide that would be generated through cement production. Estimates vary, but widespread use of RockTron's cement substitute promises to cut man-made CO2 emissions by up to 2%.

The process, which is fed by fresh and stockpiled fly ash, has the potential to level the unsightly fly ash heaps dotted around the country that are a legacy of our reliance on coal-fired electricity production.

 

A dream realised

For all these benefits, the engineers who dreamt up the patented way of refining fly ash into precisely sized beads of silica were initially dismissed as dreamers by some cement makers, and even labelled alchemists by the investment community. More worryingly, the government, which boasts of its desire to promote more sustainable technologies, ignored pleas for development funding.

RockTron founder and technical director Philip Michael, says: "They said it couldn't be done, but now it is a reality. Our new eco-mineral is exactly what British industry has been looking for. It is a 100% recycled eco-substitute that performs better than the original and costs less.

His co-founder, geophysicist Dr John Watt, says: "Nobody wanted to know when we were trying to develop our process. It is amazing that this is still a British-owned technology. We went to 53 meetings and got 53 rejections. We even tried to raise money by floating on the AIM and got frustrated by the dotcom bubble burst."

Despite the string of set-backs, the directors plugged away, until in 2007 they won a hearing from the board at electricity generator Scottish and Southern Energy.

"Scottish and Southern Energy is a commercially savvy company and quickly saw the potential for dispatching millions of tonnes of fly ash waste while producing a valuable product," explains Watt.

Attracting lots of interest

With help from the generator, the first commercial plant with a capacity to process 800,000 tonnes of fly ash each year is up and running at Fiddlers Ferry, near Widnes in Cheshire.

"Attitudes have changed now, explains Watt. "We are now getting a lot of interest from some of the cement and ready-mixed suppliers. They can finally see the benefit our product offers to the entire industry."

Paradoxically, RockTron may now even be experiencing some uninvited interest.

"We have discovered some unwanted people trying to get into our plant. It looked very much like attempted industrial espionage. Fortunately, our plant and processes are guarded by the Ghurkas and security does not come better than that," says Watt.

 

Preparing for future demand

Looking forward, RockTron is now working on plans to build a second, larger plant in the UK in anticipation of rising demand.

The CML team working on the Olympics development is interested in trialling the product, which comes out a shade or two lighter than concrete.

Elsewhere, independent ready-mixed suppliers are taking orders as they battle to deliver more competitive prices.

Initially, cost savings may prove a bigger draw than the product's carbon saving benefits.