Sustainability: Basel uses CO2-negative asphalt
The new asphalt with biochar has proven itself in initial tests and will soon be used on a large scale.
The Department of Construction and Transport of the Canton of Basel-Stadt and the Basel Institute for Building Materials Technology have developed an asphalt that binds more CO2 than its production causes. To this end, biochar is first made from green waste, with the heat released being used for the district heating network.
The Basel-Stadt Civil Engineering Office and the Institute for Building Materials Technology Viatec Basel AG have developed and tested various asphalt mixtures with different proportions of biochar. They are satisfied with the results: The biochar asphalt is of high quality and durable, demonstrates good technical properties and meets the requirements of Swiss asphalt standards. According to the Department of Construction and Transport, the costs are slightly higher than for a standard surface.
The surface has been undergoing trials since 2022 on a 450 square meter area in a recycled construction material transfer site; in future, the biochar asphalt is to be used as extensively as possible for road renovations. According to the canton's calculations, Basel-Stadt could permanently store around 1,250 tons of CO2 equivalent in Basel's roads every year - that is 450 tons more than the asphalt production caused by road construction. (ah)
