Groundbreaking research has seen microalgae waste used to create asphalt, in findings that could have a dramatic impact on road construction.
Researchers in France have been able to demonstrate a close similarity between asphalt made with materials traditionally deployed in food supplements and cosmetic dyes with petroleum-based counterparts used to build highways.
Scientists based in Nantes and Orléans produced bio-asphalt from microalgae residues, using a hydrothermal liquefaction process – pressurised water – to transform the waste into a black, viscous hydrophobic substance.
Tests are now underway to examine how the material behaves over time and its cost-effectiveness for large-scale production.
Bio-asphalt is can be used to coat mineral aggregates while ensuring cohesion of the granular structure and supporting mechanised loads and lessening stress.
The innovation could result in seismic changes for the road building industry, which is currently heavily reliant upon petroleum.
Findings are published in journal ACS Sustainable Chemistry & Engineering.