Research Project KARIN

The transport sector causes considerable greenhouse gas (GHG) emissions. A relevant proportion is generated during the production of asphalt as a road construction material - in particular through the energy-intensive production of bitumen.

In the D-A-CH countries, various technologies for the reuse and temperature reduction of asphalt are used today with the aim of reducing GHGs. Nevertheless, potentials remain unused: Higher recycling rates in asphalt surface and binder courses, further lowered mixing temperatures in asphalt production, the use of renewable energies in asphalt mixing plants and an extended service life have not been conclusively investigated for their combined effect.

The aim of the transnational research project KARIN (climate-optimised asphalt layers with reduced impact on nature and the environment) is to develop a consistent, CO₂-optimised solution for high performance asphalt pavements, to test it on a real scale and to validate it in the best possible way. The aim is to create new climate-optimised asphalt layers that result in a road pavement with a significantly lower carbon footprint than that of conventional asphalt roads. The focus is on

- The development and testing of asphalt mixtures with an reclaimed asphalt content of over 50% and up to 80%,

- lowering the mixing temperature by up to 30 °C,

- the selection of suitable regeneration agents to maintain the performance properties of the climate-optimised asphalt layers,

- maximising the use of biological additives to replace virgin bitumen,

- the constructive optimisation of the road pavement to ensure a long service life,

- the integration of renewable heat sources (e.g. solar thermal energy, biogas) into asphalt mix production,

- and the use of low-emission transport vehicles and construction machinery (e.g. HVO) for transporting and laying the climate-optimised asphalt layers.

The holistic life cycle approach (LCA according to EN 15804) chosen in the KARIN project, combined with life cycle cost analyses, ensures that all phases - from A (‘production’) to D (‘reuse’) - are taken into account. Laboratory tests based on the latest research, industrial pilot products and large-scale installation on the duraBAST test site of the Federal Highway Research Institute (BASt) are used for this purpose.

The expected results and findings include a demonstrable CO2 reduction of at least 20% compared to conventional asphalt with the same or even longer service life.

In addition, a systematic procedure for the validation of asphalt mix formulations based on a life cycle analysis as well as production and construction methods for climate-optimised asphalt layers will be established. A practical handbook for planners, authorities and construction companies will be produced in the form of a ‘Climate-optimised asphalt layers’ guide.

The KARIN project is thus making a significant contribution to achieving climate protection targets in the D-A-CH region, promoting resource efficiency in road construction and strengthening the expertise and innovative strength of clients and all other stakeholders involved. The technologies and tools gained can provide planning and construction companies as well as authorities with reliable instruments for CO₂-conscious expansion and maintenance of efficient roads.