Environmental News, News, Recycling

Corrosion-resistant concrete to combat common sewage problem


RMIT University researchers have developed a cement-free concrete that can withstand corrosion and prevent ‘fatbergs’ in sewage pipes.

The research team created a form of zero-cement concrete that can prevent sewage pipe maintenance by reducing the amount of residual lime that creates fatbergs – congealed piles of mass made up of fat, grease, oil and non-biodegradable waste such as wet wipes and nappies.

Fatbergs are notorious for clogging sewers across the globe, with RMIT stating that some can grow to 200 metres in length and weigh tonnes.

By creating a concrete that prevents free lime, which is a compound that leads to corrosion and fatbergs, the research team has created an alternative to Portland cement concrete which is frequently used in the construction industry.

The research team was led by doctor Rajeev Roychand, who said the zero cement concrete provides an eco-friendly alternative for sewage pipes.

“The world’s concrete sewage pipes have suffered durability issues for too long,” Roychand told RMIT.

“Until now, there was a large research gap in developing eco-friendly material to protect sewers from corrosion and fatbergs. But we’ve created concrete that’s protective, strong and environmental – the perfect trio.”

Zero-cement concrete is created using a blend of by-products of the manufacturing industry, including nano-silica, fly-ash, slag and hydrated lime.

Roychand said this blend could improve longevity compared with Portland cement, with the research team seeking to collaborate with manufacturers and government to use its zero cement concrete.

“Though ordinary Portland cement is widely used in the fast-paced construction industry, it poses long term durability issues in some of its applications,” Roychand said.

“We found making concrete out of this composite blend – rather than cement – significantly improved longevity.”

The zero cement concrete created in the RMIT study reduces concrete corrosion by 96 per cent.

“Our zero-cement concrete achieves multiple benefits: it’s environmentally friendly, reduces concrete corrosion by 96 per cent and totally eliminates residual lime that is instrumental in the formation of fatbergs,” Roychand said.

“With further development, our zero-cement concrete could be made totally resistant to acid corrosion.”

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