Peab Asfalt completes experiment with lignin applied in semi-warm asphalt
In Sweden, Peab Asfalt, a business area within the Nordic construction major Peab Group has announced that it has completed successful test sections using lignin in semi-warm asphalt on road 205 at Loka Brunn, Bergslagen. By replacing some of the fossil-derived bitumen with lignin that comes from the forest industry and is renewable, Peab Asfalt can further reduce its asphalt climate footprint.
At Loka Brunn on road 205 in Bergslagen, central Sweden, major reinforcement work has been carried out by Peab Asfalt. The road is served by heavy transport and is also a popular stretch of road for tourists. Some 7.5 kilometers of road has been reinforced with gravel and rock material and a new layer of semi-warm asphalt has been applied.
The asphalt that has been produced in a so-called steam turbo plant is expected to have a long service life and so do the test sections that have been carried out. On a number of test sections, lignin has been blended in which replaces some of the bitumen normally used in asphalt production.
It is important to produce test sections that give us interesting information and results that we can follow up. We have made test blends in the lab and tried to prepare for the production. It’s nice when everything works and everyone involved has done a fantastic job, said Lars Jansson, Deputy Head of the Technology Organization at Peab Asfalt.
Long trials necessary
Continued trials and more test runs are needed as evaluation takes time. Weather conditions and the impact of different seasons are difficult to test in labs, as are the real conditions once production takes place. In this experiment, a new approach to adding lignin in the manufacture of the asphalt can be evaluated.
Now a lot of subsequent analyzes remain in the laboratory and of course to follow up the test sections on the way to see the performance over time.
Semi-warm production traditionally has lower climate emissions than hot-produced asphalt and provides a longer technical life on low-traffic roads thanks to its flexible properties.
To test the properties of lignin in asphalt even with this type of coating is important for the future, both for lower emissions and to see if the lignin adds positive product properties, said Mats Wendel, Innovation Strategist at Peab Asfalt.
These test sections are part of the EU Horizon 2020 (H2020) co-funded project “REsidual soft WOod conversion to high characteristics drop-in bioFUELs” (REWOFUEL), where project partner SEKAB in Örnsköldsvik produced the lignin, a by-product of its cellulosic ethanol plant, and Peab Asfalt performs tests with lignin in asphalt production.
The project includes eleven companies from eight countries that collaborate to develop new bio-based products from waste products from forestry, including biofuels for aviation.