In 2016, the Victorian Government recognised it had a problem with waste, estimating that in that state alone, around 170,00 tonnes of flexible plastics is recycled and another 153,000 tonnes end up in landfills each year. Of the 250,000 tonnes of glass waste created, about 52% is recovered for recycling.
Sustainability Victoria in collaboration with Australian Packaging Covenant Organisation put out a call for submissions to resolve the issue. It was a call that attracted Polytrade Recycling to approach Swinburne University’s Dr Yat Choy Wong, Prof. Arul Arulrajah and Dr Alireza Mohammadinia (research team) to respond with a solution that successfully won a grant to solve the problem of Victoria’s glass and plastic waste.
Use it in cement footpaths, to save sending it to landfill.
Of the 250,000 tonnes of glass waste created, about 52% is recovered for recycling.
After more than a year’s research Dr Wong and his team have found a viable solution where end-of-life plastics and glass fines can be incorporated into concrete footpaths without compromising the mechanical properties of the concrete in any way.
“The problem is big,” says Dr Wong. “In Christmas week alone, Victorians create enough glass and plastic waste to have stock for four months. Our recycling industry has more stock than it can export to China.”
“This is a huge issue for landfill,” he says in an interview with Jobsite. “If we don’t resolve it, we need to look at opening up new landfill sites, which no-one wants in their backyard.”
Dr Wong’s research, over the course of 2017, found that recovered plastics and glass fines could be incorporated into concrete footpaths and still meet standard requirements.
“The process involved shredding the plastic and crushing the glass and investigating the effects of different percentages of glass and plastics in cement to find the optimal proportion,” he explains.
“We found that any mix of glass and plastic at 10 percent of the total footpath was fine. That could be 10 percent of glass fines, or 10 percent plastic, or even a mix of both – but 10 percent is the key ratio.”
“We found that any mix of glass and plastic at 10 percent of the total footpath was fine. That could be 10 percent of glass fines, or 10 percent plastic, or even a mix of both."
Dr Wong has submitted an article to the International Scientific Journal for review, and the Victorian Government is currently in the process of meeting with several councils to identify suitable candidates for field trials.
The research focussed almost exclusively on the environmental benefits of the aggregate cement, which include using less virgin materials in the manufacturing of the concrete, and finding an alternative use for plastic and glass waste, so Dr Wong was unable to confirm whether there are any significant economic benefits to using the new material.
“While we did not look specifically at the cost benefits, one ton of crushed glass is competitive to quarry products, which is economical,” he says.
Sustainability Victoria will be responsible for rolling out the material across the state and for promoting it at a national level.
“There is no IP on the footpath material,” says Wong. “The ratio of 10 percent waste to cement is very public, and we are happy for it to be shared. It is in everyone’s interest to find a solution to the waste, and as far as I know, the Victorian Government will happily encourage anyone to use the material,” he concludes.