• Scientists at Aston University convert mixed household waste into road surfacing material for the first time
  • New industrial process can use food waste, plastic, paper and textiles to produce a tarmac-like substance
  • Is this the beginning of the end for carbon-coughing bitumen? Study authors say ‘bio-bitumen’ is cheaper and greener to manufacture.
  • Image available. See notes to the editor.

Scientists at Aston University have developed a new way to convert organic bin waste such as decomposed food, paper and plastic into a substance suitable for laying roads and pavements.

The process, developed by academics at the university’s European Bioenergy Research Institute (EBRI) and the Aston Institute of Materials Research (AIMR), breaks down the mixed household bin waste to produce a black, highly viscous fluid similar to bitumen – a material commonly used in road surfacing.

The study, which has already received interest from Birmingham City Council and Highways England, could pave the way to a cheaper and greener alternative to the current method of extracting bitumen from crude oil, a practice that has been used to create pavements and roads in Britain since the early 19th century.

The researchers believe their material will use at least four times more “waste fraction” than the ‘plastic road’ pilots currently being tested by several UK councils.

Asphalt, produced by mixing bitumen with minerals, is one of the biggest sources of carbon emissions in road construction. In 2016 the UK produced 26 million tonnes of hot and warm mix asphalt – the equivalent of 26 million cars driving non-stop for an hour.1

If widely adopted, the method could also reduce the 7.7 million tonnes of biodegradable municipal waste that is sent to landfill each year.

The material, called bio-bitumen, is produced by placing the organic waste in a reactor and heating it to around 500°C in the absence of oxygen.

The process is called pyrolysis. It causes the chemical decomposition of organic, carbon-based materials and is often used in the production of biofuels. The researchers found that by changing the processing parameters, such as temperature, processing time and product collection strategy, they were able to alter the characteristics of the products to create a substance with very similar qualities to bitumen.

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Source: Aston University 

The research paper ‘Intermediate pyrolysis of organic fraction of municipal solid waste and rheological study of the pyrolysis oil for potential use as bio-bitumen’ published in the Journal of Cleaner Production. It can be accessed via ScienceDirect.