Construction Materials
Asphalt

Trial section of bio-asphalt hits the road in Holland

Burgess COMMENTARY

Peter Burgess

Trial section of bio-asphalt hits the road in Holland

The first ever trial section of bio-asphalt made from lignin, which covers a 100-metre section of road in the Dutch province of Zeeland, has been opened.

Asphalt.

Bitumen in asphalt is usually made purely from petroleum. But in the new material, half of the bitumen has been replaced with lignin, a renewable raw material. It is thought that if it proves successful as a road surface, it will open up the market for bio-asphalt.

It took researchers from Wageningen UR Food & Biobased Research working together with the Dutch Asphalt Knowledge Centre (AKC) just 18 months to put the idea of using lignin as a replacement for bitumen into practice.

'Lignin adheres well, is easy to process and is just as effective as bitumen in terms of UV stability and dimension stability.'

Then, it was about finding the right partners in Zeeland – including the contracting firm H4A, Zeeland Seaports and Economic Impulse Zeeland – a trial section of a road in Sas van Gent in Zeeland was resurfaced.

Just last year, researchers from Food & Biobased Research working in the laboratory discovered that lignin could be used as a high-grade bio-based replacement for fossil bitumen. “We discovered that lignin had very similar properties to bitumen,” said Richard Gosselink, co-ordinator of the Lignin Platform at Wageningen UR.

Lignin adheres well, is easy to process and is just as effective as bitumen in terms of UV stability and dimension stability, according to the scientists. “Dimension stability refers to the fact that the asphalt does not shrink or expand after exposure to rain or sun,” added Gosselink. “Lignin has a wide range of potential uses, varying from high-grade applications in products such as vanilla and bio-aromatics, for the chemical industry, to an additive in fuels.”

Wageningen UR is also about to launch a project to explore the possibilities of replacing bitumen in other products, such as roofing.

Every year, an estimated 10 million tonnes of asphalt is produced and used in the road construction industry in the Netherlands. And about 4-5% of this asphalt is bitumen.