Researchers in the Netherlands have tested roads and cycle paths that 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, and a cycle path at Wageningen University & Research, which is in three sections, each produced using a different lignin-based bio-bitumen.
Lignin shares many characteristics with bitumen. Like bitumen, lignin is a large molecule with a number of carbon rings. The researchers first thought that this similarity meant that they could just add lignin to the bitumen, like other polymer additives that are already used to improve sealants.