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Will roads soon be made out of recycled plastic… or algae ?


Plastic has become omnipresent in our societies, to the point where its production has increased by a factor of 150 in 50 years at the European level. Accordingly, producing recycled plastic and finding economic outlets for it represent priority research avenues, in order to deal with the increasing scarcity of natural resources. This is what a Dutch company is betting on, which has just unveiled its project (still at the concept stage) for roads made out of recycled plastic. Meanwhile, researchers in Nantes have developed a bioasphalt made from algae…

Only 25% of plastic is recycled at the European level, while over 55% of plastic waste are currently incinerated. This is the argument that Dutch construction firm VolkerWessels is putting forward in order to promote its PlasticRoad project. The project consists of replacing asphalt, which is responsible for 1.6 million tonnes of CO2 emissions worldwide annually, with a coating that is entirely made from used water bottles, primarily recovered from the sea they are polluting. According to the company, this process offers many advantages. The life span of the roads will be three times longer than for asphalt roads. The coating will be capable of withstanding very steep temperature changes (from -40 to +80°C), and requires less maintenance than asphalt. Its roll-out (using blocks prefabricated in factories) will also be quicker, and enables cables and other networks to be integrated more easily.

Credits: VolkerWessels

This promising project has not yet been rolled out on real infrastructure; however, the City of Rotterdam has already shown an interest in testing it in the near future.
Other avenues for renewing road surfacing materials are being explored, with a project involving bioasphalt made from microalgae particularly standing out. This is the aim of the Algoroute programme developed by French researchers from the University of Nantes and the French National Centre for Scientific Research (CNRS), which is financed by the Pays de la Loire Region. After compacting spirulina residue and applying a liquefaction process, the researchers mixed the algae with water under pressure, thereby obtaining a viscous and water-repellent black liquid that is close to oil-based bitumen and offering excellent technical characteristics. The AlgoSource Technologies company is responsible for the industrial development of this innovation.