In a recent report by FOEN, Switzerland faces a challenge regarding the recycling of asphalt in its road network. Despite efforts, a significant surplus of reclaimed asphalt remains, with around 750,000 tons ending up in landfills annually. The country’s well-developed infrastructure means few new roads are constructed, making it crucial to maximize the use of recycled asphalt during repairs.

Empa researcher Martins Zaumanis has spearheaded the HighRAP research project, collaborating with FEDRO, FOEN, Zurich and Graubünden cantons, and industry partners. The project seeks to improve the recycling process and promote the use of reclaimed asphalt. Challenges include the aging of asphalt binder, poor mixing of old and new materials, and the inconsistency of reclaimed asphalt.

Zaumanis proposes practical solutions, including standardizing reclaimed asphalt processing, calculating allowable variability based on future applications, and using “rejuvenators” to soften old binder. He also advocates performance-based testing methods.

Real-world testing on the Aathalstrasse in Uster and the Lukmanierpassstrasse has shown promise. In Uster, 30% reclaimed asphalt in the wearing course and 40-50% in the binder course proved feasible without performance loss. On the Lukmanier Pass, even harsh climatic conditions didn’t hinder asphalt with high reclaimed content.

Ongoing monitoring of these test sections will provide valuable insights into the long-term behavior of reclaimed asphalt. Calls for a landfill ban on reclaimed asphalt at the political level may further encourage complete recycling. Switzerland is taking steps towards sustainable road infrastructure through innovative approaches and practical solutions.

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