Opportunities for environmentally improved asphalt recycling: the example of Sweden

Asphalt waste from State roads in Sweden is usually recycled in order to preserve natural resources and reduce the burden on landfill. However, there appears to be a knowledge gap regarding the methods of asphalt recycling used by municipalities and private owners in Sweden. There is also a lack of knowledge regarding best practice from a life cycle environmental point of view. This study identified and evaluated potential ways of improving the life cycle environmental performance of asphalt recycling in Sweden. Data and information about the current situation of asphalt recycling in Sweden were collected through reviewing the literature and through interviews. It was observed that asphalt recycling practices were different for all three groups of road owners: the State, represented by the Swedish Transport Administration (STA), municipalities and industry. Life Cycle Assessment (LCA) methodology was used to identify processes within asphalt recycling and reuse that contribute a significant share of the total environmental impact (hotspots), and to compare the life cycle environmental performance of the main techniques used for asphalt recycling and reuse in Sweden: hot in-plant, hot in-place and reuse as an unbound material. The results showed that hot in-place recycling gave slightly more global warming potential (GWP) and cumulative energy demand (CED) savings than hot in-plant recycling. There were no savings of GWP and small savings of CED during asphalt reuse. It was concluded that asphalt recycling is environmentally preferable to asphalt reuse. However each method of asphalt recycling can provide different benefits, so possibilities exist for improving the environmental performance of the processes involved. These possibilities were subdivided into logistic, technical and organisational.