Self-Healing Concrete with Waste Materials Developed by Australian Researchers to Mitigate Corrosion
A team of researchers from the University of South Australia and the University of Queensland has created a type of concrete that can self-heal and may be effective in reducing corrosion in Australia's sewer pipes. The trial of a novel approach to address the issue of concrete pipes' corrosion is being led by Professor Yan Zhuge, a Structural Engineering professor from the University of South Australia.
The study, conducted in partnership with the University of Queensland, will involve the use of concrete pipes that incorporate microcapsules containing a combination of alum sludge and calcium hydroxide, which are included during the concrete mixing process's final stage. The microcapsules in the concrete have a shell that can sense changes in pH levels. When the acidic levels increase, the shell breaks down and releases the contents which act as a healing agent, making the concrete strongly resistant to corrosion caused by micro-organisms.
The shells of the capsules are sensitive to the pH of the pipes, and they can react when the pH reaches a specific level. This change in pH is caused by the acidic properties of sulphur-oxidizing bacteria found in wastewater, which can be corrosive. Zhuge stated that the self-healing concrete technology not only has the potential to save over $1 billion in the Australian economy by extending the lifespan of concrete structures, but it can also contribute to a circular economy by repurposing sludge that would otherwise be disposed of in landfills.
Using waste product from wastewater treatment plants in the sludge can help achieve the carbon-neutral goals of many industry operators. Professor Zhuge stated that there are around 400 drinking water treatment plants in mainland Australia, and a single site can produce up to 2000 tonnes of treated water sludge annually.Currently, most of the sludge is discarded in landfills, which costs over $6 million every year and causes severe environmental issues.
By recycling this waste product in the concrete, the research has the potential to establish a circular economy, which is critical as all industries aim to minimize their carbon footprint.
Without human intervention, 117,000 kilometres of sewer pipes in Australia might be protected from future cracking using water treatment sludge, helping to reduce yearly maintenance costs by $1.4 billion.