## 3 Results and Discussion
### Life Cycle Assessment (LCA) of Both Asphalt Mixtures
#### 3.2.3 Comparison between LCA Impacts of AC14-RCA and AC14-NA Mixtures  
A comparative analysis was conducted to understand better the environmental advantages achieved by replacing NAs with RCAs in the asphalt mixture. This comparison assessed impact values for each category between a control mixture made exclusively with natural aggregates and the alternative mixture incorporating RCAs. The analysis was limited to the mixture production phase since the direct influence of RCA incorporation is confined to this phase. As previously mentioned, the normalization process simplifies the results and enhances their analytical clarity. Thus, the same normalization process was applied to the control mixtures to facilitate a meaningful comparison between mixtures. This approach ensures that the results from both control and RCA mixtures are presented consistently and standardized. Table 15 and Figure 12 comprehensively compare the environmental impacts of the two asphalt mixtures. The impacts are assessed across various categories, highlighting the percentage reduction in environmental consequences when incorporating RCAs. The RCA mixture exhibits lower environmental impacts in most categories, highlighting its potential for enhanced sustainability. Compared to the NA mixture, the total GWP and its fossil fuel component are reduced by 7% and 6%, respectively. This reduction emphasizes the capacity of RCAs to lower greenhouse gas emissions in asphalt production. Furthermore, the RCA mixture demonstrates a remarkable 61% decrease in biogenic GWP and a substantial 62% decrease in land use and land-use change (GWP--luluc). \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Impact Category** & **Unit** & **AC14-NA** & **AC14-RCA** & **\% Decrease** \\ \hline GWP—total & kg CO\({}_{2}\) eq. & 4.04 \(\times\) 10 & 3.77 \(\times\) 10 & 7\% \\ GWP—fossil & kg CO\({}_{2}\) eq. & 4.02 \(\times\) 10 & 3.77 \(\times\) 10 & 6\% \\ GWP—biogenic & kg CO\({}_{2}\) eq. & 1.41 \(\times\) 10\({}^{-1}\) & 5.49 \(\times\) 10\({}^{-2}\) & 61\% \\ GWP—luluc & kg CO\({}_{2}\) eq. & 2.71 \(\times\) 10\({}^{-2}\) & 1.02 \(\times\) 10\({}^{-2}\) & 62\% \\ ODP & kg CFC 11 eq. & 4.90 \(\times\) 10\({}^{-6}\) & 5.34 \(\times\) 10\({}^{-6}\) & \(-\)9\% \\ AP & mol H\({}^{+}\) eq. & 1.81 \(\times\) 10\({}^{-1}\) & 1.61 \(\times\) 10\({}^{-1}\) & 11\% \\ EP—freshwater & kg P eq. & 6.15 \(\times\) 10\({}^{-3}\) & 1.98 \(\times\) 10\({}^{-3}\) & 68\% \\ EP—marine & kg N eq. & 4.55 \(\times\) 10\({}^{-2}\) & 4.91 \(\times\) 10\({}^{-2}\) & \(-\)8\% \\ EP—terrestrial & mol N eq. & 5.15 \(\times\) 10\({}^{-1}\) & 5.41 \(\times\) 10\({}^{-1}\) & \(-\)5\% \\ POC & kg NMVOC eq. & 1.38 \(\times\) 10\({}^{-1}\) & 1.50 \(\times\) 10\({}^{-1}\) & \(-\)9\% \\ ADP—mineral \& metals & kg Sb eq. & 1.12 \(\times\) 10\({}^{-4}\) & 2.92 \(\times\) 10\({}^{-5}\) & 74\% \\ ADP—fossil fuels & MJ, net calorific value & 2.81 \(\times\) 10\({}^{3}\) & 2.78 \(\times\) 10\({}^{3}\) & 1\% \\ WDP & m\({}^{3}\) world eq. & 6.85 \(\times\) 10 & 4.81 & 93\% \\  & deprived & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 15: Comparison between the core environmental impacts of the AC 14 mixture produced with NAs and RCAs. The results also reveal a 93% decrease in the RCA mixture's water depletion potential (WDP). This significant reduction in WDP highlights a crucial environmental advantage of using RCAs in asphalt production. The high water demand associated with the extraction of natural aggregates significantly contributes to WDP, and, by using RCAs as an alternative, this resource-intensive phase becomes notably more sustainable. However, it is crucial to recognize that, for specific impact categories, i.e., ozone depletion potential (ODP), eutrophication potential (EP) in marine and terrestrial environments, and photochemical ozone creation potential (POCP), the mixture with RCAs exhibits higher environmental impact values.