Introduction of a Sustainable Alternative for Bitumen : Case study of lignin-based asphalt for the Swedish market

Abstract: For some time, sustainability has been the major principle of development across the globe, and all aspects of society are somehow affected by the concept. Companies are faced with stricter regulations and are forced to look for solutions to reduce their environmental impact. A key challenge in society is reducing dependence on fossil fuels in favour of renewable materials. The asphalt industry is a sector that has a substantial environmental impact where one of the main components of asphalt is the binder, bitumen, which is produced from petroleum. One prominent alternative with notable binding capabilities, which resembles the chemical structure of bitumen, is lignin. The work on substituting bitumen with lignin has come the furthest in the Netherlands, where they have been able to substitute 50 % of bitumen with lignin. Several demonstration roads have also been laid, and extensive research on the concept is ongoing. This study was conducted with the Research Institutes of Sweden (RISE) and the LignoCity initiative. The study aims to examine the current technical- and business market situation of lignin-based asphalt, and through this, present a roadmap for the introduction of lignin-based asphalt to the Swedish market. The research method is qualitative in the form of a case study with semi-structured interviews. The gathered data was analysed and presented through the processes of thematic analysis, and a systematic combining approach was utilized throughout the study. The study highlights both obstacles and potentials for the introduction of lignin-based asphalt to the Swedish market. The main obstacles were found to be the need for long-term testing and evaluation in Swedish climate and conditions. Passive manufacturers hesitant to invest in the concept, and buyers restrained by regulations also act as significant barriers. The findings suggest that projects and collaborations between actors on the market are necessary to encourage new developments. Procurement procedures and tax-policies should also be amended to favour sustainable solutions. Benefits such as carbon sequestration, noise reduction, and lower rolling resistance should be emphasized.