Roads made from plastic could curb our waste problem
06 March 2019
MacRebur have developed and patented an innovative way to use waste plastic in roads and carparks to help solve the issue we have with waste.
MacRebur CEO Toby McCartney was working in Southern India with a charity helping people who work on landfill sites to gather potentially reusable items and sell them. He noticed that some of the waste plastics retrieved by the pickers was put into potholes and set alight until it melted to form a makeshift plastic pothole filler. It sparked an idea to use waste plastic in roads here…
Toby got together with his friends, Gordon Reid and Nick Burnett, to launch MacRebur in April 2016 – the name being based on part of each of their surnames. Toby previously owned his own training business, Gordon had his own construction business and Nick worked in council waste management. Initially based in a garage at Gordon’s house, they spent 18-months testing and trialling to find a way to safely use waste plastics in our roads. They sent off 500 samples to a UK accredited services laboratory to see if they could meet the standards required and on their 501st attempt, they nailed it.
They take plastic waste collected from commercial and household use – the split is about 60 percent commercial and 40 percent household. They can use most types of plastic but it must be classed as waste – they don’t use recycled or new plastic. They then use a granulator to turn this into small pieces of no more than 5mm. Next, the plastic granules are mixed with their activator – it’s this that makes the plastic bind properly into our roads. The activator is patented and what’s in it is a secret! This blend of plastic granules and the activator – let’s call it the MacRebur mix – then goes to an asphalt producer.
In simple terms, asphalt is made of bitumen and stone. But with this technology, part of the bitumen can be extended with the MacRebur mix – reducing the amount of fossil fuel used. They can do this because they are turning the plastic into its original oil-based state and binding it to the stone with the help of the activator. It’s not a case of burying rubbish in our roads – in fact, at the end of their life, our roads can be recycled so the plastic waste is used over and over again. Sounds good, but what about microplastics? There are no microplastics present in MacRebur roads – and they’ve carried out independent testing to make sure. That’s because they use plastic as a binder, so it melts to create a sticky substance without leaving behind any troublesome particles.
Making asphalt requires heat – usually around 180°C. MacRebur make sure that all the plastic they use melts at a temperature lower than this – around 120°C – so it homogenises properly without creating microplastics. It’s for this reason that they can’t use all plastic waste but they can use most things, including black plastic which is difficult recycle.
MacRebur plastic roads are everywhere from Aberdeenshire to Yorkshire in the UK and around the world from Australia to Dubai. And their mix has been used in asphalt on motorways, roundabouts, car parks, or plastiparks as they like to call them, airport runways and racetracks. These roads have been extensively tested in situ, with up to 50 tests on each road laid.
The plastic roads look exactly the same as regular asphalt but because they contain plastic, they are more flexible. That means they can cope better with contraction and expansion caused by changes in the weather, reducing cracks and potholes.
Actually, the roads are cheaper to manufacture because MacRebur are extending the bitumen, or oil, with waste that has no value. They also use local waste for local roads so if, for example, a MacRebur road is being laid in Cumbria, they can use waste collected by the local authority. They take this waste for free but if it went to landfill, it would cost the council money to dispose of.
With each km of road laid using the MR products, MacRebur use up the equivalent weight of 684,000 bottles or 1.8 million onetime use plastic bags. 150,000 tonnes of asphalt is used in Cumbria annually. If just ten percent of the asphalt used in Cumbria alone was made using MacRebur, 800 tonnes of plastic waste would be required. That’s more than 500 tonnes of plastic household waste the council collects in Cumbria each year.