Self‐stress and deformation sensing of electrically conductive asphalt concrete incorporating carbon fiber and iron tailings

Asphalt road gradually deteriorates in serviceability with insignificant damage. The deterioration begins with microcracks and continues until structural failure. To facilitate early damage prediction, this study proposes a structural self‐sensing technique based on the piezo‐resistive behavior of conductive asphalt concrete. To this end, conventional asphalt mixtures were modified into self‐sensing mixtures by adding conductive carbon fiber (CF) and iron tailings aggregates (TA) as alternatives for natural aggregates (NA). The self‐sensing response was evaluated by correlating fractional changes in electrical resistance (FCR) with the deformation of mixture within and beyond the elastic regime in response to varying stress amplitudes under fatigue cyclic compressive loading. From the results, it can be seen that the mixture exhibits sufficient mechanical strength and low resistivity to achieve a self‐sensing response. Furthermore, the self‐sensing response varies significantly with the stress amplitude. The mixture exhibits sufficient sensitivity to the compaction and deformation within the elastic regime by reversibly decreasing its electrical resistance at low‐stress, manifested as increase in negative (−) FCR. The −FCR reversibly decreases, reflecting initiation of microcracks due to increased deformation within the elastic regime at medium‐stress. However, irreversible FCR is observed at high‐stress due to increase in deformation beyond the elastic regime, which leads to fracture. After fracture, the mixture does not show sensitivity to stress and deformation owing to the cracking of internal conductive network. In conclusion, the mixture provides early damage prediction as sensitive damage sensor in the elastic regime and enables real‐time structural health monitoring (SHM) of asphalt pavements.