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We want to develop the material to a commercial and industry standard .
Concrete idea
When catching up over a coffee gives you a research idea .
By Emilie Lauer
It ’ s around a cup of coffee at Victoria University that Dr Yanni Bouras and his team decided to develop a way to transform takeaway coffee cups into concrete , with the aim of reducing landfill waste .
Bouras , a lecturer in built environment from VU has always been a coffee lover , drinking up to three cups a day . Turning coffee cups into concrete was a way for him to combine his love for the beverage and dealing with the guilt of using takeaway cups that are often hard to recycle .
“ We were aware of the issue with coffee cups , the volume that we ’ re disposing of in landfill and the fact that they are difficult to recycle . This motivated us ,” Bouras told Campus Review .
As a nation , Australia has a soft spot for coffee , with three in four inhabitants consuming at least one cup of coffee per day , while 28 per cent have three cups or more daily .
According to Sustainability Victoria , the majority of disposable coffee cups can ’ t be recycled through the paper recycling channel as they have a plastic liner .
In addition , Australia does not have the capacity to recycle “ compostable ” cups as the country can ’ t process the cups effectively .
It ’ s a constantly growing issue when the number of discarded single-use disposable cups of coffee reaches 2.7 million every single day .
In order to reduce the number of disposable cups in landfill , Bouras and his team decided to look at substituting a proportion of the sand present in concrete with the recycled coffee cup material .
Concrete consists primarily of four ingredients : water , cement , gravel or a coarse aggregate , and sand , Bouras said .
The team is currently looking at what proportion of the sand they can take out and replace with materials from recycled coffee cups .
“ We have done some conceptual testing , and looked at some key material properties including compressive strength , thermal conductivity , and also the workability of the concrete .
“ We ’ re still very much in the research and development phase but we have seen promising results ,” Bouras said .
So far , the VU team has conducted some preliminary testing and found that between 550 and 700 cups could be used per cubic metre of concrete to replace 10 % of the sand in the concrete batch .
In addition , by replacing 10 % of sand with takeaway coffee cups , the team has seen an actual reduction in carbon emissions associated with the production and development of the concrete mix .
“ There ’ s a lot of benefits for the environment with this type of research . If it were to go into practice , what we will be seeing is a reduction in coffee cups sent to landfill .
“ And with that , as we ’ re constructing with less sand in the concrete , we ’ re extracting less resources from the earth , which is an additional benefit .”
In terms of practical use , the “ coffeeconcrete ” shows a reduction in strength but better thermal resistance of the material . Bouras said this could potentially be used in non-structural or low-stress applications and also as an insulating product .
“ It could be used on things such as footpaths or curbs where they don ’ t experience a high loading or as a render on the facade of a building , or pavers in small retaining walls as a concrete type Besser block .”
Meticulous about the environment , the team aims to conduct further tests to evaluate the key material properties of the mix and optimise it for future real-life applications .
“ We need to verify a range of different strength parameters , the workability of the mix , the durability properties , things like how does it react to water and exposure to chemicals ?
“ We want to ensure that the product itself doesn ’ t give off any micro plastics or leachate , as we call it , and harm the environment that way ,” Bouras said .
“ Our ultimate goal is to see this applied in practice . We want to develop the material to a commercial and industry standard where we can see it applied in real life projects .”
In order for Bouras and his team to see a real-life application of their research , a partner industry or a local government willing to support the project will be needed , which the team is already looking for .
“ We ’ re always trying to reach out and partner up either with builders or councils or anyone in the construction industry .
“ It is always difficult , but there is a lot of interest with this particular project as a lot of people love coffee ,” Bouras said . ■
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