Metal-Loaded Biochar for Low-Emission and Long-Lasting Asphalt

Volatile organic compound (VOC) emissions and premature aging of asphalt pose significant environmental and resource management challenges. This study evaluates metal-loaded biochar (Fe, Zn, and Cu) as a sustainable modifier to reduce VOC emissions and enhance asphalt durability. Fe-loaded biochar achieved up to a 73.7% reduction in VOCs, with Fe and Zn particularly effective against aromatic and long-chain alkanes, and Cu targeting small molecular alkanes. Rheological analyses indicate that metal-loaded biochar increases asphalt stiffness and deformation resistance. Moreover, both short-term and UV aging tests demonstrate that biochar modification improves antiaging performance, attributed to the adsorption of polar compounds and stabilization of aging byproducts. By extending pavement lifespan and reducing the need for repaving, this dual-function approach promotes resource conservation and supports a transition toward greener, more sustainable infrastructure practices.