## 4 Results Analysis
### Effect of Reactive Additive on the Test Accuracy of SBS Content
#### 4.4.2 Mechanism Analysis  
The infrared spectrum of the first group of SBS-modified asphalt at 966 cm\({}^{-1}\) whether it contains added stabilizer are shown in Figure 7, and the peak area test results are shown in Table 7.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Stabilizer** & **Test Sample** & **SBS Modifier** & **A966/(A966 + A1377)** & **Stabilizer** & **Test Results** & **Actual SBS** & **Error** \\ \hline \multirow{4}{*}{2} & First group & 4\% & 0.1075 & 0.2\% & 3.43\% & 3.99\% & \(-0.56\%\) \\ \cline{2-8}  & Second group & 4\% & 0.0675 & 0.2\% & 3.46\% & 3.99\% & \(-0.53\%\) \\ \cline{2-8}  & Third group & 4\% & 0.1046 & 0.2\% & 3.52\% & 3.99\% & \(-0.47\%\) \\ \cline{2-8}  & Fourth group & 4\% & 0.0717 & 0.2\% & 3.50\% & 3.99\% & \(-0.49\%\) \\ \hline \multirow{4}{*}{4} & First group & 4\% & 0.0964 & 0.25\% & 3.1\% & 3.99\% & \(-0.89\%\) \\ \cline{2-8}  & Second group & 4\% & 0.0634 & 0.25\% & 3.25\% & 3.99\% & \(-0.74\%\) \\ \cline{2-8}  & Third group & 4\% & 0.0850 & 0.25\% & 2.75\% & 3.99\% & \(-1.24\%\) \\ \cline{2-8}  & Fourth group & 4\% & 0.0450 & 0.25\% & 2.02\% & 3.99\% & \(-1.97\%\) \\ \hline \end{tabular}
\end{table}
Table 6: Test results of SBS-modified asphalt with stabilizer.  
Figure 7: Infrared spectrum of SBS-modified asphalt with and without stabilizer at 966 cm\({}^{-1}\).  
As can be seen from Figure 7, the characteristic peak area at 966 cm\({}^{-1}\) is significantly reduced after adding the stabilizer. The data in Table 7 prove that the added stabilizer produces a large experimental error and far exceeds \(\pm\)0.1%. It proves that the adding of the stabilizer caused a change in the characteristic peak area at 966 cm\({}^{-1}\); that is to say, the number of trans =CH bonds in polybutadiene represented by 966 cm\({}^{-1}\) in the SBS modifier has changed greatly, so it can be concluded that the C-H bond here has broken and other chemical bonds have been formed, which cause the obvious change of characteristic peak area at 966 cm\({}^{-1}\).  
The commonly used stabilizers in the market are mainly elemental sulfur, polysulfide, or sulfur-containing cross-linking agent. The structure of butylene is shown in Figure 8. There are three chemical bonds in the existing polybutadiene that may react with the stabilizer, which are the C=C double bond in position 1 at butadiene, the =C-H bond represented by the characteristic peak at 966 cm\({}^{-1}\) in position 2, and the C-H bond in the methylene group of position 3. Under the action of the stabilizer, SBS will produce self-crosslinking. Because the C=C double bond of the polybutadiene segment is active, the double bond will break, and the breaking double bonds produce self-crosslinking, resulting in the spatial network structure. In addition to the self-crosslinking, the C=C double bond in butadiene will break into a single bond and branch with other functional groups in asphalt to achieve the stability of the chemical bond. The C-H bond in methylene and the =C-H bond represented by the 966 cm\({}^{-1}\) characteristic peak in the infrared spectrum will also break and lose the H atom under the action of additives, and the H atom combines with the heteroatom functional group in asphalt to form a new chemical bond, namely an SBS-asphalt graft. Because the chemical reaction between SBS and asphalt results in the reduction in the =C-H bond represented by 966 cm\({}^{-1}\) in the infrared spectrum, so the characteristic peak area at 966 cm\({}^{-1}\) of the SBS will decrease with the adding of stabilizers, while the characteristic peak area at 1377 cm\({}^{-1}\) in the base asphalt will not change, so the peak area ratio A966/(A966 + A1377) in the SBS content test will be reduced; therefore, it will cause an error in the test results. Therefore, it can be concluded from the above that the adding of stabilizer will affect the test accuracy of SBS modifier content.