Li, et al (2024) Study on the Adhesion Performance of Biochar-Modified Asphalt Based on Surface Free Energy and Atomic Force Microscopy. Coatings. https://doi.org/10.3390/coatings14111390

Recent research highlights the potential of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More as a modifier to improve asphalt adhesion, with significant benefits for road durability and moisture resistance. Using biochar derived from municipal sludge and waste wood, scientists explored how biochar-modified asphalt behaves on both micro and macro scales, using advanced techniques like Atomic Force Microscopy (AFM) and surface free energy (SFE) measurements.

Biochar improves the asphalt’s microstructure by increasing the presence of bee-like structures—microscopic formations associated with adhesion—while reducing their size. This uniform distribution enhances the overall bonding strength and stability of the asphalt. Furthermore, the biochar’s porous structure supports this effect by anchoring the asphalt molecules, reducing their movement and enhancing surface roughness, which facilitates stronger physical adhesion to aggregates.

Tests confirmed that biochar boosts the asphalt’s SFE, especially its dispersive component, leading to better resistance against moisture-induced damage. This finding is particularly valuable, as greater SFE generally indicates a more stable and durable bond between asphalt and aggregate.

In summary, incorporating biochar into asphalt not only promotes environmental sustainability by recycling waste materials but also improves road longevity and performance. The study provides foundational data for the future development of biochar-modified asphalts that are more durable, eco-friendly, and resistant to adverse weather effects.