The new asphalt mixture was used to pave part of the wood field at Stora Enso's Sunila Mill and the road leading to the mill's harbour area. The kraft lignin used in the asphalt has been extracted in the pulp production process at the Sunila Mill. Stora Enso is the world's largest producer of kraft lignin; Sunila Mill has a capacity of 50,000 tonnes of kraft lignin per year.
Lignin is a natural binder in wood that can be used as a substitute for oil-based bitumen in asphalt. The purpose of the test paving is to determine the overall impact of lignin on the properties of asphalt and its carbon footprint. Lignin can also be used as a substitute for fossil-based raw materials, for example, in batteries and adhesives.
The test will monitor the load and wear resistance of the test pavement, including its ability to withstand weather and seasonal variations, high loads and torsional forces.
"We see this as an excellent development for our mill. We are proud to bring a more environmentally friendly asphalt made from our own Lineo® lignin to the Sunila Mill. This innovation is a great way to celebrate the 150-year history of Stora Enso in Finland and the forest industry in Kymenlaakso area", says Timo Tidenberg, Sunila Mill Director.
"We are doing our part to develop our operations and products to reduce our carbon footprint. The practical coating applications provide us with important information for further development. This project is linked to our efforts to replace fossil fuels and raw materials with bio-based products. Last year, Peab launched ECO Asphalt, which replaces fossil fuel with biofuel," says Nina Orttenvuori, Research and Development Manager at Peab Asfalt.
This is Stora Enso's first lignin paving project in Finland. Stora Enso and Peab Asfalt have already tested lignin-based asphalt on several roads in Sweden.
Recently, Stora Enso and Svevia tested lignin-based asphalt in Sweden. (Article in Swedish)