LCA Sensitivity Analysis of Asphalt Modified Nano Silica

Improving long-term resilience of asphalt, various types of modifiers have been investigated to facilitate the development of an advanced asphalt mixture. Nanoparticles with silica layers have gained the interest of pavement researchers because of their contribution to improving the physical, rheological, and mechanical properties of asphalt binders. However, the environmental impact information on using this material is limited. Therefore, further investigation needs to be conducted to assess the environmental burden of incorporating the material into the asphalt mixture. Life Cycle Assessment (LCA) is a key method for evaluating the environmental impacts of new materials such as Nano Silica in asphalt mixtures. Nonetheless, many LCA input parameters are based on estimations or generalisations, such as transport distances and production data. These introduce uncertainty and may significantly affect results. Therefore, a sensitivity analysis was conducted to test how changes in key variables influence total impact category across life cycle stages. The results show that raw material production contributes the highest impact to mineral resource scarcity and global warming, while the asphalt mixing stage dominates freshwater ecotoxicity and energy consumption. Mineral resource scarcity is most sensitive to nano-silica and binder production, freshwater ecotoxicity to electricity use, and both global warming potential and energy demand to thermal energy in the mixing process.