## 4 Conclusions  
This study on high-performance asphalt binders modified with Trinidad Lake Asphal (TLA) and styrene-butadiene-styrene (SBS) polymers demonstrates the potential to achieve a robust balance between workability, flexibility, and durability. Comprehensive evaluations of physical, rheological, and mechanical properties underline the effectiveness of these modifications in enhancing the performance of TLA-modified binders for modern pavement engineering. 1. The incorporation of TLA and SBS has a notable impact on binder viscosity. Moderate amounts of TLA (10-20%) combined with SBS (up to 5%) maintain satisfactory workability. However, a higher SBS content raises viscosity, reducing workability and necessitating increased mixing and compaction temperatures to address this issue. 2. The DSR test results reveal substantial enhancements in rutting resistance with the addition of SBS, particularly at higher dosages. The optimal combination of 20% TLA and 15% SBS provides exceptional resistance to permanent deformation, making it a prime candidate for pavements subjected to high temperatures and heavy traffic loads. 3. TLA increases stiffness and rutting resistance, but excessive rigidity is mitigated effectively by incorporating SBS. Moderate SBS levels restore flexibility while maintaining compliance with Superpave performance criteria, emphasizing the role of SBS in balancing stiffness and flexibility. 4. The % recovery and non-recoverable compliance (Jnr) data indicate that binders with 15% SBS exhibit superior elastic recovery and minimal deformation under loading, \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & & & & & RTFO + PAV & & & \\ \hline \multirow{4}{*}{**Combination**} & \multirow{2}{*}{**PG64-22**} & PG64-22 + & PG64-22 + & PG64-22 + & PG64-22 + & PG64-22 + & PG64-22 + & \\  & & 10\%\(\uparrow\)TLA & 20\%\(\uparrow\)TLA & 10\%\(\uparrow\)TLA + 5\% & 20\%\(\uparrow\)TLA + 5\% & 10\%\(\uparrow\)TLA + & 20\%\(\uparrow\)TLA + \\  & & & & & SBS & SBS & 10\%\(\uparrow\) SBS & 10\%\(\uparrow\) SBS \\ \hline \multirow{4}{*}{**Combination**} & PG64-22 & - & S & S & S & S & S \\ \cline{2-7}  & PG64-22 + 10\%\(\uparrow\)TLA & - & - & S & N & S & S \\ \cline{1-1} \cline{2-7}  & PG64-22 + 20\%\(\uparrow\)TLA & - & - & - & S & S & S \\ \cline{1-1} \cline{2-7}  & PG64-22 + 10\%\(\uparrow\)TLA + 5\% SBS & - & - & - & - & N & S & N \\ \cline{1-1} \cline{2-7}  & PG64-22 + 20\%\(\uparrow\)TLA + 5\% SBS & - & - & - & - & - & S & N \\ \cline{1-1} \cline{2-7}  & PG64-22 + 10\%\(\uparrow\)TLA + 10\% SBS & - & - & - & - & - & - & S \\ \cline{1-1} \cline{2-7}  & PG64-22 + 20\%\(\uparrow\)TLA + 10\% SBS & - & - & - & - & - & - & - \\ \hline \hline \end{tabular} S–significant; N–non-significant.  
\end{table} 
Table 9: Results of statistical analysis of the m-value (RTFO + PAV) of modified bituminous binders at \(-12\)\({}^{\circ}\)C as a function of various combination (\(\alpha\) = 0.05). even after RTFO aging. This confirms the suitability of these formulations for high-performance applications in heavy traffic and extreme climatic conditions. * While an SBS above 7.5% is typically considered highly modified, this study investigated higher dosages (10-15%) due to the 20% TLA substitution limit. The results confirm that increasing SBS enhances elasticity and rutting resistance, with 15% SBS achieving >88% recovery and Jnr < 0.01 kPa\({}^{-1}\). However, increased viscosity at higher SBS contents necessitates careful consideration of workability. * The combination of 20% TLA with 10% SBS emerges as the optimal formulation, providing a balance between performance and practical usability for high-traffic, extreme climate pavements. Overall, the findings validate the use of TLA and SBS-modified binders as a sustainable solution for constructing durable and long-lasting flexible pavements. The combination of 20% TLA with 10% SBS emerges as the optimal formulation, balancing workability, durability, and high-temperature performance without compromising low-temperature flexibility.