Iowa State University’s Christopher Williams was just trying to see if adding bio-oil to asphalt would improve the hot and cold-weather performance of pavements.
What this American scientist found was a possible green replacement for asphalt derived from petroleum.
Now his idea is being put to the test with a demonstration project. A section of a bicycle trail in Iowa is being paved with an asphalt mixture containing what is now known as Bioasphalt.
If the demonstration and other tests go well, “this would be great stuff for the state of Iowa,” says Mr Williams, an associate professor of civil, construction and environmental engineering.
His belief is that asphalt mixtures derived from plants and trees could replace petroleum-based mixes.
That could create a new market for crop residues. It could be a business opportunity. And it apparently saves energy and money because Bioasphalt can be mixed and paved at lower temperatures than conventional asphalt.
Bio-oil is created by a thermochemical process called fast pyrolysis where a mix of biomass materials are quickly heated without oxygen.
The process produces a liquid bio-oil that can be used to manufacture fuels, chemicals and asphalt plus a solid product called biochar that can be used to enrich soils and remove greenhouses gases from the atmosphere.
A team of Iowa alumni have set up a company, Avello Bioenergy, to push the idea forward.
It begs the question … might this approach work here in Britain, especially if it delivers tougher pavements that, as a bonus, also possess green credentials.