Workers are paving a runway at Germany’s Frankfurt Airport using an innovative material sourced from cashew shells. This eco-friendly asphalt concrete, tested as part of Frankfurt Airport’s sustainability efforts, aligns with its aim to reach zero carbon emissions within the next two decades.

Traditional asphalt concrete combines bitumen—a residue from refining crude oil—with aggregate materials. However, German start-up B2SQUARE has developed a more environmentally-friendly version, named “BioBitumen.” According to the airport, this organic bitumen is created by blending a natural hydrocarbon resin with a cashew shell extract.

Axel Konrad, project manager at Frankfurt Airport Services, highlights two major advantages: quality and carbon impact. “First, we expect a much higher quality from this organic bitumen, as it avoids the quality inconsistencies often found with oil-based bitumen. Secondly, we anticipate that this material will lead to at least a carbon-neutral road surface,” Konrad explained.

B2SQUARE claims that BioBitumen can sequester approximately 3,400 pounds of CO2 for every 2,200 pounds of bitumen produced due to the carbon captured in the cashew shells. Additionally, they report that this bio-based bitumen lasts up to ten times longer than its conventional counterpart.

To assess the performance of both materials, Frankfurt Airport has paved one side of a 650-foot road with bioasphalt and the other with regular asphalt. A successful trial could see bioasphalt playing a significant role in the airport’s environmental transformation.