## 3 Results and Discussion
### Mechanism Performance
#### 3.1.4 Adsorption Efficiency of Mineral Powder  
The peak areas were calculated (OMNIC software) for sample C and asphalt binder in the wavenumber range 2750-3000 cm\({}^{-1}\) (Figure 4), the results are shown in detail in Table 5. The intensity of the peak in 2919 cm\({}^{-1}\) was connected to the biggest adsorption efficiency of 4.1%, while the peaks in correspondence of 2845 cm\({}^{-1}\) and the range 2750-3000 cm\({}^{-1}\) were 3.8%. Based on the peak areas for selected wavenumbers, the adoption ratio for mineral powder can be estimated as equal to 4%.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Wavenumber** & **Assignment** & **Origin of the Chemical Structure** \\
**(cm\({}^{-1}\))** & **Assignment** & **Origin of the Chemical Structure** \\ \hline
2919 & Methylene C–H anti-symmetry stretching & Methylene units \\
2845 & Methyl C–H symmetry stretching & Methylene units \\ \hline \hline \end{tabular}
\end{table}
Table 4: Peaks and assignments for the FTIR wavenumber range 2750–3000 cm\({}^{-1}\).  
Figure 3: FTIR spectra for pure asphalt binder and the three samples.  
Considering the outcomes from FTIR and XRF analyses, no formation of new functional groups was detected, proving that the adsorption exerted by the mineral powder only involves physical processes and no chemical reactions. Previous research revealed that the surface of the mineral powder was quite rough, thus improving the adhesive effect to asphalt binder [43; 44]. As shown in Figure 5, the adsorption mechanism for the mineral powder can be explained considering three phases. The addition of mineral powder in the solution promotes contact between asphalt compounds and the rough surface (a); then, part of the dissolved compounds sticks to the mineral powder's surface (b) and forms the sediment by constant accumulation (c). Therefore, the achievement of adsorption should be attributed to the contact between the mineral powder and asphalt binder phase, promoted by the rough interface of the former. These series of reactions are physical activities, which would not affect any compositions or ingredients of the original gasoline.  
The dissolved asphalt binder did not reach the maximum solubility of gasoline in this experiment [45]. Increasing the amount of dissolved asphalt in the gasoline solution also increased the probability of mineral and asphalt components creating contacts. The practical situation occurring in asphalt laboratories usually corresponds to supersaturated solutions of massive waste asphalt binder handled by limited gasoline solvent. Therefore, it can be stated that a higher content of dissolved asphalt could entail an adsorption ratio that is better than the one investigated (4%).  
Figure 4: Selected sections for calculating peak areas.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Peak Wavenumber (cm\({}^{-1}\)) and Areas**} \\ \cline{2-4}  & **Section 1 (2919 cm\({}^{-1}\))** & **Section 2 (2845 cm\({}^{-1}\))** & **2750–3000 cm\({}^{-1}\)** \\ \hline
70\# asphalt & 17.385 & 7.845 & 62.362 \\ Sample C & 0.710 & 0.295 & 2.369 \\ Percentage (\%) & 4.084 & 3.760 & 3.799 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Peak areas for selected wavenumbers.