Aussie researchers develop cement-free concrete resistant to acid corrosion

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Researchers from RMIT University have developed an eco-friendly zero-cement concrete that protects sewers from corrosion and fatbergs and could significantly reduce the cost of maintaining sewage networks.

Concrete corrosion and fatbergs plague sewage systems around the world, costing billions in repairs and replacement pipes.

The cement-free concrete can withstand the corrosive acidic environment found in sewage pipes, while eliminating free lime – a chemical compound that promotes corrosion and fatbergs.

Project leader Dr Rajeev Roychand said the new concrete reduces corrosion by 96% and totally eliminates residual lime that is instrumental in the formation of fatbergs, making it perfect for use in major infrastructure, such as sewage drainage pipes.

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

“Until now, there was a large research gap in developing eco-friendly material to protect sewers from corrosion and fatbergs.

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“But we’ve created concrete that’s protective, strong and environmental – the perfect trio.”

RMIT’s cement-less concrete is composed of by-products of the manufacturing industry, including a zero cement composite of nano-silica, fly-ash, slag and hydrated lime.

Roychand said that not only does their cement support a circular economy through the use of large volumes of industrial by-products, it surpasses 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,” Roychand said.

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

Roychand and his team are looking to collaborate with manufacturers and government to develop more applications for their zero-cement concrete.

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