Wageningen Food & Biobased Research is taking the lead to replace bitumen in Dutch asphalt on a large scale with the natural binder lignin. This is done in the TKI project CHAPLIN, in which it collaborates with partners from the asphalt production chain. One of the advantages of lignin instead of bitumen in asphalt is that it significantly reduces CO2 emissions and capture it for long time.
“There is major interest in lignin as a raw material for bio-asphalt, says lignin expert Richard Gosselink of Wageningen Food & Biobased Research. “The supply of bitumen, which is made from petroleum, is under pressure worldwide and the quality fluctuates strongly. The natural adhesive lignin is an excellent alternative because, like bitumen, it gives structure and support to asphalt and it can be produced in large quantities. By replacing half of bitumen with lignin, CO2 emissions are already reduced by 20% because the greenhouse gas is stored in the road for a long period of time. A huge advantage is also that lignin can be produced at much lower temperatures than bitumen; so much less energy is needed.”
Gradually replacing bitumen by lignin
Gosselink has been working on lignin as a raw material for asphalt for more than eight years. Since 2015, lignin asphalt has been used in various locations in the province of Zeeland, and in 2017 the world's first 'lignin cycling path' was laid out on Wageningen University & Research campus. In all these places, lignin seems to easily measure up to bitumen. "That looks promising", says Gosselink: "Lignin is released in enormous quantities during the production of paper and cardboard, but is mainly used as low-grade fuel for energy generation. In the Netherlands alone, 300,000 tons of bitumen are processed in asphalt every year. If you look at Europe, this number is as much as about 15 million tons per year. So there is a significant potential for lignin. And the market is ready to gradually replace bitumen with lignin, provided that the production of suitable lignins, including lignin produced in the Netherlands, is strongly increased in the coming years.”
Other types of lignin
The partners in the TKI project CHAPLIN (Collaboration in aspHalt APplications with LIgniN) want to give a boost to the use of lignin as a raw material for asphalt in the coming years. “In recent years, we have already developed an essential part of knowledge for this technology in Wageningen”, says Gosselink. “In this project we will further test this technology with other types of lignin from Dutch biomass residual flows, such as wood, straw and grass. We will test new applications extensively, in the lab and by paving demonstration roads at various locations. We are also looking at how we can optimize the production process, monitor the lignin asphalt in the user phase and how we can integrate lignin asphalt after use into the recycling process to which the asphalt sector is accustomed.”
Wageningen Food & Biobased Research coordinates the TKI project CHAPLIN in cooperation with Biobased Delta, Utrecht University, Asfalt Kennis Centrum (AKC), TNO, H4A, NTP, Dura Vermeer, Latexfalt, Vertoro and Avantium Chemicals. The project started with a kick-off on 24 February 2020 and will continue until the end of 2021. It is the first granted project of the broader CHAPLIN research program, in which a consortium of about twenty companies, governments and knowledge institutions is working together.