The state of Hesse is testing alternatives to conventional asphalt in an attempt to find a heatproof substitute that doesn’t break or become deformed in the hot weather.

Heatwaves can make for dangerous driving conditions

Hot weather can cause serious problems for drivers in Germany. Since heatwaves in Germany are becoming more common, the state of Hesse is focusing on creating a new road surface that could potentially replace existing asphalt roads. 

According to Dirk Kronewald, from the Hessen Mobil road and traffic management team, concrete roads are the ones most at risk from heat waves. "[Hot weather] creates stresses in the concrete roadways. Old and / or previously damaged concrete can then break, the so-called blow-up. Asphalt softens with heat and deforms when heavy loads are repeatedly applied to it by trucks," he told Stern.

Road surface tests have been taking place in Hesse since 2020

In Offenbach, there is a test track where the patent-pending "Klimaphalt" road surface has been being trialled since 2020. "It consists of a road structure with a depth of 60 centimetres and a light surface that reflects the sunlight better than dark asphalt," explained press spokesperson Fabian El Cheikh to Stern. 

Research is also taking place at the University of Kassel, focusing on how a geothermal system could be used to cool asphalt in summer and also prevent the buildup of snow and ice during the winter season. "The thermal energy gained is stored in a heat exchange system and released again in winter," Konrad Mollenhauer, professor in the Department of Civil and Environmental Engineering and supervisor of the research, told Stern.