Bio-bitumes: virtuous roads based on microalgae
In France, the share of road transport still accounts for nearly 80% of travel.
The situation does not seem to have to change radically in the coming years, so in this context, reducing the environmental cost of road infrastructures, strengthening their safety and efficiency are essential research areas.
Today’s road is beginning its transformation through the Roman road, towards the paved road, then the paved road and currently the 4th generation of roads “highways”.
Scientists are asking is what could the future 5th generation road look like?
With this in mind, Ifsttar1 has built a major project called “Route de 5e Génération ” is imagine the post-oil era with among other bio-bitumen.
Algae serving the roads of tomorrow.
Source : Libération
Such an alternative was developed between 2011 and 2014 by the Algoroute program, supported by research institutions (University of Nantes, CNRS, Ifsttar), companies linked to the culture of microalgae and supported by the Pays de la Loire region. .
Micro-algae have been known for a long time for their applications as dyes in cosmetics or as food supplements. Their refining to produce, for example, biofuels, is an idea that has emerged in recent years.
Just like conventional bitumen comes from oil residues, this bio-bitumen comes from the remains of the culture of micro-algae, used to make cosmetics, food supplements or biofuels.
Thanks to a technical process, this transforms this micro-algae waste into a hydrophobic black viscous phase (bio-bitumen) with an appearance similar to that of a petroleum bitumen.
Its black color and its physicochemical properties give it characteristics that allow it to cohere the granular structure, to withstand the loads and to relax in case of strong mechanical stresses.
Time-bound analyzes have begun, as well as studies to evaluate the profitability of the process in the perspective of large-scale production.
This innovation brings a potential new option for the road industry, which is currently entirely dependent on oil.
Until now, bio-bitumen developed incorporated oils of agricultural origin (with the disadvantage of competing with human nutrition) or from the paper industry, mixed with resins to improve their viscoelastic properties.
Tomorrow, the use of micro-algae, whose cultivation does not require the mobilization of arable land, therefore presents an attractive solution.
Nevertheless, large-scale integration with measured costs remains a challenge.
Ifstar 1 : Institut français des sciences et technologies des transports, de l’aménagement et des réseaux.