THE GREAT COMPOSERS
Plastic technology goes on the road with Russell Edson and Ben Palmer
Plans to trial the use of reclaimed plastics to fill in potholes and repair road surfaces have generated considerable interest for a variety of reasons. Using new generation polymer road surfaces could bring significant performance and cost benefits, at the same time as helping to protect the environment.
But the potential for using waste plastics in road design and development doesn't end there and innovation is currently underway that could help to leverage 5G connectivity and pave the way to the self-driving future.
Earlier this year, the UK Government announced plans to spend £4.5 million to trial new plastic composite materials designed to prevent potholes and repair road surfaces. The funding is part of a wider commitment to invest £22.9 million in plastic road technology in a bid to future proof UK highways. The real-world trials are initially focused in eight local authorities across the UK - Buckinghamshire, Bedfordshire, Cumbria, Staffordshire, Kent, Reading, Suffolk, Solihull and Birmingham – and if successful, the technology could be rolled out nationally. Some of the funding will be used to extend an existing road in Cumbria, which has been built from an asphalt mix including a combination of bitumen and non-recyclable plastic, and the trial in Buckinghamshire will explore the use of recycled plastic to manufacture columns for lighting sensors and 5G antennas.
Using waste plastics in road surfaces can help to reduce the cost of road surfacing and repairs by reducing the use of raw materials such as bitumen. Finding an alternative use for non-recyclable plastics could also help to reduce environmental pollution by limiting the amount that ends up in landfill and in the ocean.
“Finding an alternative use for non-recyclable plastics could also help to reduce environmental pollution by limiting the amount that ends up in landfill and in the ocean”
Among the benefits of polymer road surfaces is their ability to withstand extreme temperatures. Conventional mixes have a tendency to buckle or melt at high temperatures or to crack during cold conditions. Oxidation can also cause asphalt road surfaces to crack or rut. Incorporating waste plastics into such mixes has been shown to improve temperature stability, strength, and durability. However, examples of their use in road construction are more limited and while some international test cases exist, long-term outcomes are not yet known.
Plastic material has been used in road surfacing applications in North America and Europe for several decades. However, this has involved the use of virgin plastics. In a bid to improve the sustainability of such applications, Scottish company MacRebur (see article in Thinking Highways’ June issue, pp 62-64 of the print edition) is seeking patent protection for a road-surfacing material comprising a specific mix of aggregate, bitumen and plastics. In the UK, the MacRebur plastic product has been used by Durham County Council in the UK for resurfacing a section of A689 near Sedgefield and for resurfacing runways and taxiways at Carlisle Airport. MacRebur is also currently involved in the construction of South Africa's first plastic road.
Despite this progress, some challenges remain, which should be carefully managed to facilitate wider use of polymer road surfaces. One frequently cited concern surrounds the potential release of microplastics from photodegradation of plastic-enhanced roads; potentially contaminating the surroundings.
“One frequently cited concern surrounds the potential release of microplastics from photodegradation of plastic-enhanced roads; potentially contaminating the surroundings”
In a bid to solve this problem, operators must carefully sort and select certain plastics then process them to ensure full homogenisation into the bitumen mix and thereby avoid the presence of microplastics in the resulting asphalt. This restricts the types of plastic that can be incorporated and increases processing costs. However, with developments in chemical activators and waste separation technologies, these costs should decrease.
Waste plastics could also perform a vital role in helping to future-proof UK highways – helping to upgrade them to facilitate driverless motoring and create opportunities for greater vehicle/infrastructure connectivity. As part of the roll-out of 5G technology across the UK, which the Government has recently committed to supporting further, the increased bandwidth and low latency it offers will enable near real-time communications applications with high reliability. To take advantage of this functionality, prefabricated hollow box road structures, made from plastic, in which key services such as power lines can be housed, are currently being trialled in the Netherlands by the Plastic Roads partnership. Waste plastics could also be used to manufacture other key elements of 5G infrastructure such as antennas and masts, which will need to be more numerous and placed much closer together than existing 4G masts. Some of these technologies are likely to form part of various Government-backed testbeds and trials, currently getting underway across the UK, to identify opportunities for 5G, including the UK's first multi-city 5G test bed in the West Midlands.
To encourage wider take-up of all-electric motoring in the future, the Government recently announced funding for more electric-charging infrastructure on residential roads. A number of alternative electric-charging technologies are currently under development, including some induction-based systems, which could be built into the road surface itself to support charging while driving. The use of waste plastics to support the delivery of 5G connectivity across Britain's road network could help to make such technological advancements possible and commercially viable.
“The use of waste plastics to support the delivery of 5G connectivity across Britain's road network could help to make such technological advancements possible and commercially viable”
In a rapidly evolving technological landscape it is vital that innovators seek suitable IP protection, including patents on technical innovations, design protection on product appearance, and trademark protection on key brands, in all relevant global territories. Taking this approach will enable them to make the most of any early-mover advantage, whilst protecting their commercial position using their IP rights as the market develops. Securing patent protection at an early stage could open the door to licensing opportunities further down the line, especially if their technologies become standard-essential. A historical parallel can be drawn from the introduction of tarmac at the turn of the last century, the process for which was patented by Edgar Purnell Hooley in 1902, facilitating the early and continued success of the Tarmac Group.
“For the UK’s road network there is an opportunity to harness this innovation to improve the durability and resilience of road surfaces, while helping to make smart cities and driverless motoring a reality”
Finding new uses for waste plastics is a dynamic area of cross-industry research and development and many innovative companies are now involved in developing technologies for existing and future applications. For the UK’s road network there is an opportunity to harness this innovation to improve the durability and resilience of road surfaces, while helping to make smart cities and driverless motoring a reality. Given the current demand for safe and sustainable ways of re-using plastic waste in the road networks, there is a ripe opportunity for innovators in the sector to clean-up, in all senses of the phrase.