Valorization of spent coffee grounds into biochar for sustainable asphalt pavements: A combined molecular dynamics and experimental study

Document Type

Article

Publication Date

2-14-2026

Abstract

Landfilling waste coffee grounds has a significant impact on greenhouse gas emissions and soil degradation. To address this environmental challenge, while promoting sustainable pavement technology, this study explores the utilization of coffee grounds charcoal as a novel asphalt modifier. A combined experimental and molecular dynamics simulation approach was employed to evaluate the compatibility and performance of CGC modified asphalt. The storage stability test confirmed that CGC had significant compatibility with base asphalt. The results of the physical performance test showed that the penetration value decreased by 33.6 % and the softening point value increased by 22.8 %. This indicates that the addition of CGC significantly enhanced the high-temperature deformation resistance. Although the low-temperature flexibility was slightly reduced, the test results of rheological properties also confirmed this point. To elucidate the modification mechanism, molecular dynamics simulation was conducted. The solubility parameter difference between CGC and asphalt was found to be 1.96 (J/cm³)^0.5, confirming favorable miscibility. The high binding energy of −154 kcal/mol indicated strong intermolecular interactions, particularly with the light component. The diffusion coefficient of CGC-modified asphalt decreased from 1.348 × 10⁻² to 1.068 × 10⁻², and the increased motion of the light component corresponded to the observed rise in viscosity. These results confirm the dual benefits of CGC as an effective strategy for waste valorization and a high-performance asphalt modifier. The macro-micro integrated approach provides a foundation for optimizing the formulation of biochar modified asphalt in sustainable road applications.

Publication Title

Construction and Building Materials

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