Value-added recycling of plant waste for modification of asphalt pavement used aggregates: Interface enhancement and carbon sequestration

Abstract

The durability of asphalt pavements depends heavily on the interaction between the aggregate and asphalt. Despite its significance, there are few clear and environmentally friendly methods for directly managing this interface. In this study, a value-added wood waste recycling method is introduced that creates a porous carbon structure (Pc-S) on the aggregate surface. This modification process uses thermal cross-linking technology, in which biochar is converted at high temperatures into carbon on the aggregate surface in an activation reaction. Chemical bonds, specifically CO, CO, and SiC, effectively anchor the Pc-S layers to the aggregate. As the asphalt solidifies, mechanical interlocking occurs at the interface, significantly increasing its strength. This carbon modification of granite not only fortifies the interface but also enhances its water intrusion resistance by over 78.9 %, outperforming basalt, which is one of the best aggregates for pavement construction. Moreover, using these modified aggregates in road construction can lead to negative carbon emissions, estimated at 349.23 tCO₂/km. This study is applicable to large-scale road infrastructure construction and provides a new solution for creating long-life green pavements.