Circular sludge solution for concrete pipes to be trialled

A team of researchers led by University of South Australia’s Professor Yan Zhuge will trial a world-leading solution to heal cracked concrete in pipelines, a maintenance problem worth hundreds of millions of dollars annually in Australia.  

The university said in a statement on Monday that the team – which also includes researchers from the University of Queensland – will develop capsules with a pH-sensitive shell. These contain a core with alum sludge – a by-product of wastewater treatment plants – and calcium hydroxide powder. 

Acid from bacteria in wastewater is part of a series of problems that affect the lifespan of pipes.

The solution would be “highly resistant to microbially induced corrosion” and be embedded in concrete at the final step of mixing to protect it from breakage. “When the pH value changes as acid levels build up, microcapsules will release the healing agents,” according to Uni SA.

“Sludge waste shows promise to mitigate microbial corrosion in concrete sewer pipes because it works as a healing agent to resist acid corrosion and heal the cracks,” said Zhuge.

“This technology will not only extend the lifetime of concrete structures, saving the Australian economy more than $1 billion, but it will promote a circular economy as well by reusing sludge that would normally end up in landfill.”

The project is being supported by a $501,504 Australian Research Council grant.

Picture: ABC Radio Brisbane/Craig Zonca