RMIT University scientists have developed a new zero-cement concrete to deal with fatbergs and sewage system corrosion.
Fatbergs are globs of congealed mass that clog up sewers with fat, grease, oil and non-biodegradable junk like wet wipes and nappies, some growing to be 200 meters long and weighing several tons.
These build-ups in sewers and pipelines – as well as corrosion over time – often lead to costly and disruptive maintenance, these running in the billions.
Now RMIT professor Dr Rajeev Roychand and his team have found a way to combat this by creating a concrete that does away with free lime – a chemical compound known to promote corrosion and fatbergs.
According to Roychand, the new solution is more durable than ordinary Portland cement, making it a perfect choice for use in major infrastructure, such as sewage drainage pipes.
The key ingredient of this cement-less concrete is a zero cement composite made up of nano-silica, fly-ash, slag and hydrated lime.
Not only does the new RMIT concrete use large volumes of industrial by-products supporting a circular economy, it also managed to surpass sewage pipe strength standards set by ASTM International.
“Though ordinary Portland cement is widely used in the fast-paced construction industry, it poses long term durability issues in some of its applications,” notes Roychand.
“We found making concrete out of this composite blend – rather than cement – significantly improved longevity.”
“Our zero-cement concrete achieves multiple benefits: it’s environmentally friendly, reduces concrete corrosion by 96% and totally eliminates residual lime that is instrumental in the formation of fatbergs.”
“With further development, our zero-cement concrete could be made totally resistant to acid corrosion.”
Image and content: Rob Zugaro/RMIT
