Willmott Dixon has replaced carbon-intensive bitumen with an innovative method that uses non-recyclable plastic on roads at the Ashton Rise housing development in Bristol.
The new method uses waste that would otherwise have gone to incineration or landfill, saving the equivalent of 150,000 single-use plastic bags.
Willmott Dixon claimed it would also save 1.6 tonnes of carbon entering the atmosphere and because it contains plastic, the asphalt will be more flexible, meaning it can cope better with movement caused by changes in the weather, reducing cracks and potholes.
To deliver this scheme, waste management company ETM collects any non-recyclable plastic from the Ashton Rise site before plastic road company MacRebur processes it so that the resulting asphalt can be laid back at the development by Gworks Surfacing. Because the plastic melts into the mix, there are no microplastics present, Willmott Dixon claimed.
Neal Stephens, managing director for Willmott Dixon in the South West, said: “This innovation is also complemented by low-carbon heating which is also being installed at the site, making Ashton Rise a highly sustainable development with individual homes making lifetime carbon savings of 23.5kg.
“By showcasing these innovative solutions to support carbon waste reduction, we hope to inspire other developers.”
Toby McCartney from MacRebur said: ‘‘Sustainability is a key part of the Ashton Rise development so it’s fantastic to see our technology being used here to repurpose plastic which would otherwise have gone to incineration or landfill for the roads and footpaths across the site.’’
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Could this method potentially be applied to A / M roads or runways / Taxiways?
There is no such thing as a free lunch.
There is a lot of talk about micro-plastics in the environment at the moment. As this abrades with use, what will stop the resulting micro-plastics being washed into watercourses?
This is a brilliant question Jonathan and it deserves a good answer. Plastic has been used in road construction since the ‘60s. These plastics are added into asphalt to create what is known as PMB (Polymer Modified Bitumen) and we are doing exactly the same thing. We take plastic waste, out of green bins (less than 30% of UK plastic waste is recycled) and instead of burning or burying this valuable material, we mix it with our activator. This activator bonds at one end with plastic and the other with bitumen, this creates a WPMB (Waste Polymer Modified Bitumen).
So in one move we reduce the amount of oil-derived bitumen being used, we reduce the amount of CO2 being released and we give value to plastic waste. Asphalt roads can continuously be recycled, meaning we have created a closed loop whereby this material is locked in our roads indefinitely. We have had to make sure that this assumption rings true and have had to do a lot of testing in the background, with universities to make sure that as cars, buses and HGVs roll over the surface we have not got plastic leeching out into the soil and watercourses, we have categorical evidence that this is not the case. Far worse to have these plastic burned into the atmosphere, or dumped indefinitely underground where they leech out into the soil and water courses, or even worse than those two options, plastic waste being dumped directly into rivers and seas.
In answer to Nic: This waste plastic material has been used on 800+ roads in the UK mainly in the north east of England. Starting in 2016 in Cumbria on small schemes repairing damage of storm Desmond, and now in 2019 being used on the A689 dual carriageway. This will be rolled out as we gain more credibility and have our materials used on Highways England Strategic Road scheme. In 2017 Carlisle airport had their taxiway and runway paved with this material, we are a long way off being used on Heathrow’s 3rd runway however, we are trying.