Deakin University scientists have developed a cost-effective method to turn contaminated soil from waste into an alternative material for fine aggregate in concrete.
With an increased reliance on landfill, more contaminated soils from settings such as construction sites are being dumped at landfill.
Per- and poly-fluoroalkyl (PFAS) contaminated soil are treated by thermal destruction to decontaminate the soil. Through appropriate heat treating, Deakin University Associate Professor Will Gates found that the soil could be used for fine aggregate in concrete.
“Our study has shown that the millions of tonnes of PFAS contaminated soil currently being disposed in increasingly limited landfill at a relatively high cost, and potentially posing long-term environmental and health concerns, could instead be re-used in concrete, after heat treatment, to destroy PFAS,” Gates said.
Through heating in excess of 600 degrees Celsius, Deakin researchers found that the aggregate had equivalent hardened and structural integrity properties to reference concrete – following VicRoads, Australian and international standards.
As the most widely manufactured material globally, the concrete industry emits circa 5-8 per cent of the worlds CO2 output.
Gates believes that this alternative form of concrete aggregate production could reduce the environmental impacts of conventional methods.
“Though the concrete industry globally has made steps to reduce its carbon footprint where it can, the re-use of treated PFAS decontaminated soil would contribute to further reducing that footprint, rather than it going untreated to landfill,” he said.
Deakin is now looking to conduct large scale testing of the material.