# A Practice for the Application of Waste in Road Asphalt Pavements in an Eco-Friendly Way
## 3 Results and Discussion
### Performance Evaluation Based on MCDA and Sensitivity Analysis  
In this section, ELECTRE I methodology was applied to the normalized matrixes of the analysed alternatives (see Table S2). The obtained results revealed that HMA\({}_{\text{binderJGW}}\) was the optimal solution for the binder layer, while CMRRARAP\({}_{\text{GW}}\) was the optimal solution for the base layer in terms of the four defined groups (HP, LP, EHP and MP) with constant weights of 25%. As indicated by the concordance and discordance values determined for the binder layer (Figure 3(a1,a2)) and base layer (Figure 3(b1,b2)), HMAs exhibited the lowest concordance and highest discordance indices as compared to thresholds c* and d*, respectively. Consequently, the HMA solutions were outperformed by the other solutions in all pairwise comparisons. In terms of the engineering performance evaluated both at high and low temperatures, HMA\({}_{\text{binderJGW}}\) was often preferred to the other hot asphalt mixtures designed for the binder layer because its concordance and discordance indices were higher than the c* threshold (see Figure 3(a1)) and lower than the d* threshold (see Figure 3(a2)). However, the HMA\({}_{\text{binderFA}}\) performance was better than that of HMA\({}_{\text{binder}}\) and worse than the performances of the other mixtures fabricated from the marginal materials. On the contrary, HMA\({}_{\text{binderCDW}}\) was never preferred to the other hot asphalt mixtures (see Figure 3(a1)), except for HMA\({}_{\text{binder}}\) due to its higher S value at 40 \({}^{\circ}\)C.  
Considering the base layer alternatives, the hot asphalt mixtures were less favourable than CMRAs because they reached the highest average values of the discordance indicesfor the environmental indicators (see Figure 3(b2)). CMRA\({}_{\text{RAPIGW}}\) was always preferred to HMA\({}_{\text{base}}\), HMA\({}_{\text{baseJGW}}\) and HMA\({}_{\text{baseFA}}\) (\(-34\%\) for all impact indicators on average) as well as to CMRA\({}_{\text{RAP}}\) in terms of HP, MP and EHP, as indicated by the concordance indices presented in Figure 3(b1). Meanwhile, the discordance indices of the CMRAs were slightly below or little above the discordance threshold d* as compared to the hot asphalt mixtures in terms of LP (see Figure 3(b2)) and especially ITSM at 20 \({}^{\circ}\)C and N\({}_{\text{f}}\). Although the hot asphalt mixtures are outranked by the CMRAs, HMA\({}_{\text{baseJGW}}\) exhibits the lowest discordance index among the base layer alternatives compared with that of the  
Figure 3: Comparing alternatives: concordance indices and their relative thresholds determined for the (**a1**) binder layer and (**b1**) base layer; discordance indices and their relative thresholds obtained for the (**a2**) binder layer and (**b2**) base layer. HMA\({}_{\text{baseFA}}\) solution, indicating that even its worst indicator (FR) was not very different from the best value obtained for the hot asphalt mixtures. In general, as opposed to JGW and FA, CDW addition resulted in small environmental benefits and worsened the LP characteristics as compared with that of HMA\({}_{\text{binder}}\). A sensitivity analysis was conducted to corroborate the MCDA results by varying the weights of the four groups of indicators (see Figure 2) to obtain 24 different scenarios, as described in Section 2.3. Figure 4a,b shows the solutions selected for the binder and base layers, respectively, at least one time as the best alternatives (their concordance indices were above the concordance threshold, while the discordance indices were below the discordance threshold) with weight configurations that made them preferable to the other solutions. The selection frequency of the best solutions for the \(p\)-th alternative (\(f_{p}\)) was calculated via Equation (10).