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On Monday 1 November, a special stretch of road was laid at the Midgraaf in Almkerk. During maintenance, a layer of bio-asphalt was applied. This test section forms part of the CHAPLIN TKI project. This is part of the national CHAPLIN programme that develops asphalt in which part of the fossil raw material (bitumen) is replaced by a bio-based raw material (lignin).

With the development of lignin asphalt, the programme wants to contribute to the greening of road construction and reduce CO2 emissions. The municipality of Altena is one of the frontrunners that makes it possible to gain knowledge and experience with this bio-based asphalt. The aim is to be able to use it on a larger scale in the future and thus contribute to making road construction greener.

Asphalt that stores CO2

Lignin is a substance that is a natural binder and provides strength, as it does in plants and trees. It is released as a residual flow during the production of pulp and cellulose, among other things. When lignin is created, during the growth of plants and trees, carbon dioxide is absorbed from the atmosphere and, once processed into asphalt, is fixed in the road for a long time. An additional advantage is that lignin offers road builders an alternative raw material for (fossil) bitumen. Improvements in petroleum refining processes are putting the quality and availability of the residual product bitumen under increasing pressure.

Alderman Roland van Vugt: “This innovation fits in nicely with the sustainability ambitions of the municipality of Altena. In terms of surface area, Altena is the largest municipality in Brabant. We therefore manage many kilometres of asphalt. It is great if we can make asphalt more sustainable through innovation and cooperation. Altena is happy to contribute to this.

Large-scale pilot project

In the meantime, 25 test strips of different lignin-based asphalt compositions and for different road uses have been monitored. Trial strips like the one in Almkerk make it possible to expand experience and knowledge in the production and processing of this asphalt. In addition, tests are being carried out on working conditions and environmental aspects. Life cycle analyses must map the environmental performance and climate gains over the entire chain in order to contribute to its upscaling. These are components of the CHAPLIN TKI (TBBE119007) project, which has been made possible by a grant from RVO (Netherlands Government Office for Entrepreneurship). Richard Gosselink, coordinator CHAPLIN TKI and biorefinery and lignin expert, of Wageningen Food & Biobased Research (WFBR): “The first results are encouraging. It looks like there will be a climate-friendly alternative to traditional asphalt that performs at least as well in terms of lifespan and load and weather resistance.”