Congratulations to CIES PhD researcher Soheil Heydari

The 3MT format requires higher degree researchers to speak to the core of their years’ long and incredibly detailed research to communicate their work – its reasons, findings and uses  – to the public, yes in just three minutes.

Soheil’s thesis topic is The Application Of Recycled Plastic In Asphalt. His supervisors are Scientia Professor Nasser Khalili and Dr Ailar Hajimohammadi.

During his presentation Soheil explained the following stark realities.

Only nine percent of waste plastics in Australia are currently being recycled. Since plastics are usually mixed in with and contaminated by other materials, such as colours and chemicals, the recycling process is very challenging, and very expensive.

So what happens to them if not recycled? Simply, they are buried underground. 9 million tons of waste plastics are landfilled in Australia every single year. And, says Soheil, ‘given the fact that the degradation of the waste plastics takes up to 400 years, we all know that we are facing a big problem.’

So what could possibly be the solution?

This is what his PhD research is about: to find an application for waste plastics in road construction.

Roads are usually made from a combination of stones with a binding element which holds the stones together. The common binder for road constructions is bitumen. In the last 200 years it has been used all around the world. But bitumen is very expensive and is ultimately not good for the environment.

Soheil’s mission is to use waste plastics instead of bitumen. ‘It’s going to be two birds with one stone!’, he explains. ‘We are going to make the roads green, and use the waste plastics at the same time.’

 The good news is, last year Soheil’s team made a breakthrough.

‘We figured out a very smart process. By mixing different types of waste plastics, and doing some special treatments, we created a very sticky black material, that looks very similar to bitumen. With three main differences though.

First, it is way cheaper than bitumen. Secondly, it outperforms bitumen. And thirdly, it is environmentally friendly.’

This is the first binder material that has been created 100% from waste materials. The novel technique works with any type of plastic and is not sensitive to contaminations at all.

If all new roads in Australia were made using this novel binder, says Soheil, there will be no waste plastic left to bury under the ground.  

‘It’s 100 percent from waste plastics,’ says Soheil, ‘so even though its black, it is very green.’

Soheil’s 3MT was chosen to represent CIES at the School’s final round by a panel of judges, our thanks to CIES academics Ailar Hajimohammadi, Taehwan Kim. Johnson Shen, and Mohammad Vahab.

Soheil and the School’s 3MT runner up Esta Qui, a transport researcher from rCITI will go forward to the UNSW Faculty of Engineering’s round.