Targeted and highly effective technique for healing the aggregate-asphalt interface

Diverging from the conventional approach of directly incorporating conductive additives into asphalt to develop electrically conductive asphalt concrete (ECAC), this study introduces a novel method for developing conductive aggregate-based asphalt concrete. By utilizing carbon nanotubes-polymer nanocomposites (CNTP) as a conductive coating on the aggregate surface, highly effective healing of the interface between the aggregate and asphalt is achieved with the assistance of microwave radiation. The research focuses on evaluating the impact of CNTP coating on the surface properties of aggregate, as well as cracking resistance, microwave-heating capability, and microwave-heating healing properties of asphalt concrete. The experimental findings exhibit the rapid temperature increase of the conductive aggregate upon microwave radiation, reaching 90–115 ℃ within just 30 s. Compared to traditional conductive asphalt-based ECAC, the conductive aggregate-based ECAC exhibits a significantly higher surface heating rate of 0.772 ℃/s, resulting in surface temperatures of approximately 100 ℃ after 60 s of microwave radiation. To ensure optimal self-healing efficiency within a reasonable construction timeframe, it is recommended to allow ECAC a resting period of nine hours between damage-healing cycles, with a maximum of five cycles suggested for reliable microwave-heating healing performance. These results hold promising implications for practical applications of the conductive aggregate-based ECAC, providing enhanced construction efficiency and durability.