## 4 Discussion  
The study demonstrates a novel approach to recycling bitumen-based roofing materials (BBRM) by integrating them with plastic waste to create composite materials with superior  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Sample** & **Onset**, \({}^{\circ}\)**C** & **End**, \({}^{\circ}\)**C** & **Peak**, \({}^{\circ}\)**C** & **TML 600 1** \\ \hline
1 & 342.8 & 459.0 & 428.9 & 47.4 \\
2 & 352.3 & 473.2 & 451.3 & 53.5 \\
3 & 372.5 & 466.1 & 449.4 & 60.7 \\
4 & 347.2 & 347.2 & 347.2 & 61.7 \\ \hline \end{tabular} \({}^{\dagger}\) Total mass loss at 600 \({}^{\circ}\)C, %.  
\end{table}
Table 3: Key thermogravimetric data of the samples.  
Figure 7: Thermogravimetric analyses.  
mechanical properties. Unlike conventional recycling methods that primarily involve crushing BBRM for road paving or energy recovery, this process yields a material with improved tensile strength, flexibility, and resistance to environmental degradation. These advancements highlight significant progress toward sustainable construction practices.  
The results reveal that composites prepared with specific ratios of polyethylene (PE) and BBRM exhibit distinct improvements in mechanical properties, particularly compressive and flexural strength. These improvements can be attributed to the chemical bonding between bitumen and PE, as evidenced by thermogravimetric analysis. The presence of a matrix structure within the composite contributes to its enhanced performance, with bitumen particles occupying voids within the matrix and bonding weakly to the plastic.  
Flexural strength results suggest a steep decrease under certain conditions, which is hypothesized to stem from the tearing of the matrix structure beyond its tensile limit. This phenomenon emphasizes the composite's potential to achieve significant material performance gains with proper formulation and processing conditions.  
Challenges during material preparation, such as achieving uniform heating and mixing of high-viscosity SBS-containing materials, underscore the need for further refinement of processing techniques. The pilot-scale apparatus addressed some of these limitations, offering insights into practical scalability and operational efficiency.  
The results also highlight the limitations of current analytical methods in fully characterizing the composite's structure and bonding mechanisms. Advanced techniques like atomic force microscopy (AFM) and environmental scanning electron microscopy (SEM) could provide deeper insights into the material's microstructure, enabling further optimization.  
The process described aligns with the principles of the circular economy by repurposing construction waste into high-value materials, reducing dependency on virgin resources, and minimizing greenhouse gas emissions. The successful fabrication and testing of roofing components for real-world applications further validate the composite's potential for widespread industrial use. However, long-term monitoring of these components is essential to establish durability under varying environmental conditions.  
To enhance the utility and applicability of the developed composite material, future research should focus on the following:  
* Refining the pilot-scale apparatus for industrial production.
* Exploring alternative polymer blends to further enhance material properties.
* Conducting long-term field studies to evaluate performance under real-world conditions.
* Expanding the range of applications for the composite beyond roofing, such as structural reinforcements or thermal insulation.  
This study lays a robust foundation for advancing sustainable materials in construction, addressing the pressing need to mitigate waste and reduce environmental impacts in the industry.