Real-time monitoring of internal damage evolution in asphalt mixture based on electrical resistance measurements

Internal voids in asphalt mixtures enhance flexibility and load-carrying capacity; however, dynamic interactions among these voids can lead to internal damage under complex loading conditions. While X-ray computed tomography is effective in characterizing microstructural changes, it lacks real-time monitoring capabilities. This study addresses this limitation by modifying conventional asphalt mixtures with conductive additives to track internal damage progression in real-time through localized changes in electrical resistance. Our findings reveal that under low cyclic compression, the mixtures effectively self-monitor its densification and the ability to perform consistently without internal defects as indicated by stable gauge factor (GF) and negative fractional changes in electrical resistance (–FCR). At medium strain levels, the mixture transitions to partially reversible strain changes, highlighting the early onset of internal damage, and the GF providing critical insights for timely maintenance to mitigate further deterioration. At high strain levels, the transition to irreversible strain leads to localized damage, marked by shifts in GF and a transition to +FCR, indicating critical weaknesses in the mixture that compromise its ability to manage extreme deformation. The ability to detect, respond to and mitigate internal damage highlights the dynamic adaptability of these mixtures under different loading conditions. The proposed method helps to detect damage at an early stage and can be used as a preventive measure to avoid further deterioration of asphalt mixture without the need for additional non-destructive evaluation techniques.