A recent study in Next Materials by S. Mahalakshmi, Revathy Jayaseelan, and Gajalakshmi Pandulu investigates the integration of coconut shell biochar as a sustainable, bio-based modifier to enhance the performance and durability of hot-mix asphalt pavements. Flexible pavements are vital for global transportation networks, but they frequently experience severe distresses such as rutting, thermal cracking, and moisture damage when exposed to intense traffic loading and changing weather conditions. To mitigate these issues, the researchers produced coconut shell biochar through controlled laboratory pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More and incorporated it into a standard penetration-grade asphalt binder at various dosage levels.

The findings indicate that adding biochar creates a stiffer, more thermally stable binder by absorbing lighter fractions and improving internal structural rigidity. Comprehensive mechanical testing demonstrated that a 12.5% biochar dosage achieves an optimal balance between structural stability and flexibility, satisfying standard engineering specifications for heavy-traffic roadways. Furthermore, volumetric analyses confirmed that appropriate biochar replacement maintains air voids within the recommended 3% to 5% range to ensure proper compaction. Moisture sensitivity assessments also showed that the modified mixtures exhibit superior tensile strength ratios, proving their enhanced resistance to water-induced stripping and premature structural failure.

Source: Mahalakshmi, S., Jayaseelan, R., & Pandulu, G. (2026). Microstructural and mechanical performance of coconut shell biochar modified asphalt for sustainable pavement applications. Next Materials, 11, 101595.