## 3 Results and Discussion
### Life Cycle Assessment (LCA) of Both Asphalt Mixtures
#### 3.2.2 LCA Global Results for Asphalt Mixtures
ADP for minerals and metals underscores the resource-intensive nature of this extraction, emphasizing the depletion of non-renewable resources. The water depletion potential (WDP) also indicates its impact on water resources, highlighting the importance of sustainable water management practices. Figure 10 shows the contribution of each input flow to the main environmental impacts of AC14-RCA in Module A. While RCA's environmental impacts are linked to its recycling process, primarily the diesel consumption involved, it helps to reduce the environmental footprint of asphalt mixtures by replacing conventional aggregates with recycled materials. Thus, developing more efficient and sustainable RCA recycling methods is imperative for maximizing these benefits. The analysis of the heating process indicates a significant contribution to the overall carbon footprint, with substantial GWP primarily driven by emissions of greenhouse gases, particularly carbon dioxide (CO\({}_{2}\)). Thus, measures to reduce the impact of this process on global warming and climate change shall be studied. Additionally, the heating process contributes to the ODP, highlighting the potential release of ozone-depleting substances, although in relatively small amounts. It highlights the importance of addressing ODP concerns and reducing GWP emissions to ensure a more sustainable and environmentally responsible approach to asphalt mixture production. Examining the results presented for each impact category at this stage, the environmental benefits of replacing NA with RCA in the asphalt mixture production process become evident. Nevertheless, making direct result comparisons can be challenging due to the inherent unit variations within each impact category. Therefore, a normalization process was employed to standardize the data and facilitate result interpretation. Normalization quantifies the degree to which an impact category indicator deviates from a chosen reference point, whether relatively high or low. This approach furnishes valuable insights into the specific impact category outcomes concerning a selected benchmark. Each impact per emission unit was divided by the total impact of all substances within the same category per person and year (for Europe) to normalize the results. This standardization process mitigates unit incompatibility and enhances the clarity of conclusions, enabling a more coherent evaluation of the results, as shown in Figure 11.  
Figure 11: Normalization of the LCA results of the AC14-RCA. It can be noticed that the most significant impact category is ADP--fossil fuels (ADPf), with bitumen emerging as the primary contributor. The data reveals that ADPf has an exceptionally pronounced impact compared to all other factors. This prominence in the normalized value directly results from assessing the average annual consumption per inhabitant across various products. Consequently, the graph illustrates that ADPf stands out as the most significant impact category related to using bitumen in producing asphalt mixtures. The global warming potential (GWPt), acidification potential (AP), eutrophication potential (EP), and photochemical ozone formation potential (POCP) are other indicators with normalized values worth mentioning, which are not so dependent on the bitumen contribution, but also on the RCA and heat influence. Finally, the results demonstrate that AC14-RCA mixtures have a negligent influence on the ozone depletion potential (ODP), abiotic depletion potential for non-fossil resources (ADPmm), and water deprivation potential (WDP) because the consumption of these resources in asphalt mixtures is significantly lower than the average European consumption per person.