Researchers from RMIT University (Melbourne, Australia) have developed an eco-friendly zero-cement concrete able to withstand the corrosive environments found in sewer pipes. This concrete significantly reduces the residual free lime that promotes corrosion and contributes to fatbergs, the congealed masses of fat, grease, oil, and non-biodegradable solid matter found in sewer systems.
The RMIT research team is led by Dr. Rajeev Roychand, who says the zero-cement concrete solution is more durable than Portland cement, making it ideally suited for major infrastructure such as sewage drainage pipes.
“The world’s concrete sewage pipes have suffered durability issues for too long,” says Roychand. “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.”
The RMIT-produced concrete is composed of industrial byproducts such as nanosilica, fly ash, slag, and hydrated lime. Along with using large volumes of these byproducts, the concrete surpasses sewer pope 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 says. “We found making concrete out of this composite blend—rather than cement—significantly improved longevity.”
The RMIT team is looking to collaborate with manufacturers and government entities to develop additional applications for its zero-cement concrete. According to Roychand, this concrete could be made totally resistant to acid corrosion with further development.
More information about the zero-cement project can be found in the January 2021 edition of Resources, Conservation and Recycling.