Air QualityEnvironment & ClimateFossil FuelsNews

What alternatives are being developed to replace asphalt/bitumen roads?

By September 8, 2020 No Comments

As the world begins to transition towards a Covid contingent lifestyle, many issues which were prevalent before the pandemic, have now begun to be discussed once again, most notably, Climate Change.

Across the UK Green Groups are calling on the UK government for a ‘Green Recovery’ desperate to learn lessons from the pre-Covid climate & eager to implement an environmental focussed economic recovery.

However, one of the UK Governments most recent announcements regarding a £27.4bn road plan has not been welcomed by Green Groups.

‘On Friday Highways England set out the latest stage in its roads strategy, confirming plans to deliver £14bn of projects to repair, replace, and increase the capacity of motorways and major A roads across the country. The agency said the move would support 64,000 construction industry jobs, providing a major boost to the government’s economic recovery plans.’ (1)

With an upsurge in homeworking during lockdown leading to a dramatic decrease in private cares being on the road & with many businesses seeing ‘home working’ as a future business model for their industries; there surely is more of a need to upgrade the Broadband services across the UK, rather than expand the road networks.

Dolphin N2 has already looked at the extensive Government funding & investment for public transport pre-lockdown, which has of course now been undermined by the Government dissuading travellers from using public transport to slow the spread of Covid19.

However, in a contradictory move, the ‘Department for Transport’s hotly anticipated Transport Decarbonisation Plan due for release later this year, has signalled that the Government will set out a strategy to reduce private car use in favour of making public transport, walking & cycling “the natural first choice for our daily activities”. (1)

Despite the push by the UK government for a more effective & efficient roads systems to be in place, a recent article in the New Scientist has highlighted an environmental issue surrounding the emissions from asphalt/bitumen.

Asphalt/bitumen has been discovered to be an increasingly dangerous form of air pollution.

‘Peeyush Khare at Yale University and his colleagues placed samples of asphalt into an enclosed furnace so they could study their emissions in detail. They subjected them to temperatures ranging from 40°C to 200°C. Total emissions doubled when the temperature rose from 40°C to 60°C, which are typical temperatures for asphalt on a Californian summer day.’ (2)

The pollutants released during the Yale University experiment were all carbon based often with 12 to 25 carbon atoms per molecule. (2)

“Many of these compounds are conducive to condensing to form secondary organic aerosol after reacting in the atmosphere,” says co-author Drew Gentner, also of Yale University. This can, in turn, go on to form tiny particles called PM2.5, which are one of the most dangerous types of air pollution for human health. (2)

Despite some innovative companies such as MacRebur patenting new & innovative ways of recycling our plastics into new road coverings; it still does not answer the issue of the emissions still prevalent in the bitumen, which is still used in the MacRebur process (3)

‘After years of tests and trials all over the world, MacRebur now promote 3 waste plastic additives into asphalt. All of the products meet various worldwide roads standards and have been rigorously tested against standard asphalt, bitumen and Polymer Modified Bitumen.’(3)

‘The numbers & data in relation to the MacRebur product, speaks for itself. For each km of road laid using the MacRebur product, they use the equivalent weight of 684,000 bottles or 1.8MT of single use plastic bags. 1 tonne of the MacRebur road mix contains the equivalent of 80,000 plastic bottles.’ (3)

However, there are companies who are seeking out to eradicate the use of bitumen all together & therefore, reduce the harmful emissions it can cause in an ever increasingly hotter climate.

PlasticRoad based in the Netherlands, laid it’s first cycle path using its patented & innovative modular road covering in September 2018. The PlasticRoad innovation is fully sustainable & is a circular product that is based on recycled plastics. It has a significantly smaller carbon footprint than traditional road structures thanks to the longer lifespan and the reduction of transport movements involved in its construction. (4)

Another alternative to bitumen for road infrastructure, is the use of a naturally occurring polymer known as Lingin – a complex natural polymer, which normally provides firmness to plant tissues. (5)

The Netherlands already have test roads & cycle paths which are paved with a bitumen-like product made from the natural binder lignin.

These include a section of road on an industrial site—used daily by cars and heavy trucks, some minor roads, & a cycle path at Wageningen University & Research, which is in three sections, each produced using a different lignin-based bio-bitumen. (6)

Despite the human need for freedom of movement becoming more & more important in a post lockdown society, there area also considerations which need to be made about the construction materials being used to sustain road infrastructures. It is reassuring to read about the innovators who are forging ahead with new & alternative technologies to achieve these goals.

Written by Katy-Jane Mason for & on behalf of Dolphin N2.