Assessing the Ecological Impact of Different Asphalt Mix Designs Following a Cradle-to-Gate Approach

The consequences of climate change are becoming increasingly noticeable and require a more economical use of resources and energy in all areas, including road engineering. To optimize such construction processes, a comprehensive assessment of the respective impacts is essential. By conducting a Life Cycle Assessment (LCA) according to ISO 14040/44, following a cradle to gate-approach (Module A1–A3 according EN 15804), the focus of this study is set on manufacturing (Module A3). Production data from an asphalt mixing plant with possible addition of cold recycled asphalt pavements (RAP) has been collected and analyzed to identify and evaluate various indicators which may have an influence on the energy consumption of the drying drum. In addition, a suggestion to sensibly cluster asphalt mix designs into groups according to their respective energy consumption for production and their components will be presented, in order to be able to compare the ecological impacts of different mix designs based on their Global Warming Potential (GWP). The results have shown that the addition of RAP and/or polymer-modified bitumen (PmB) are increasing the fuel consumption and consequently the GWP in Module A3. However, when considering the whole product phase (Module A1–A3), this additional emission can be offset with the benefits in Module A1 by the addition of RAP.