Turning hospital waste into longer-lasting concrete through a new recycling project is the goal of researchers with Deakin University (Geelong, Victoria, Australia). Specifically, they plan to use shredded plastic waste from dialysis treatment to help better protect structural concrete from corrosion.
“Concrete can crack and damage the internal bond, which can then lead to water penetration and corrosion of the steel bars, critical for providing the strength and integrity of concrete structures,” says Riyadh Al-Ameri, senior lecturer in structural engineering.
Tubes carrying blood and dialyzer are made of plastic designed for single use only, which leads to significant waste from each treatment. Because the waste is potentially infectious, it also must be either burned or sterilized—creating major financial or environmental costs, researchers say.
During initial testing, Al-Ameri’s team added the shredded plastic waste to a concrete mix at concentrations of 0.5% and 1.0% by weight. Results showed a concrete product that was more durable and significantly more waterproof. “The 30% decrease in water absorption we found is significant and would be expected to improve resistance of concrete to corrosion,” Al-Ameri says.
Funded by Fresenius Medical Care (Bad Homburg, Germany), Al-Ameri’s team plans to conduct more rigorous testing to see if the mix stands up to harsher conditions.
“We will use our accelerated weather corrosion tanks in the concrete lab to simulate a marine environment,” Al-Ameri says. “Wet and dry cycles can have a big impact on durability, and seawater has chloride, which is very harmful to both concrete and steel reinforcement.”
Potential applications include offshore rigs for oil and gas, observation towers, coastal concrete buildings exposed to humidity, and marine structures such as retaining walls.
Source: Deakin University, deakin.edu.au.