Asphalt mixtures with embedded piezoelectric smart aggregates for nondestructive ultrasonic monitoring

The objective of this study is to develop a new concept and method of asphalt mixtures with embedded piezoelectric smart aggregates for ultrasonic nondestructive monitoring. Ultrasonic waves, as the detecting signals, are generated and received with the embedded piezoelectric smart aggregates. In the proposed method, an array of piezoelectric smart aggregates with fixed locations is used, leading to faster and more automated monitoring processes and enhanced data accuracy. The analysis of ultrasonic signals is conducted using wavelet packet energy analysis and coda wave interferometry, based on the direct responses received from the piezoelectric smart aggregates. The corresponding effects of two key factors, temperature and frequency, on propagation of ultrasonic waves are studied. Finally, damage experiments and ultrasonic monitoring for asphalt mixture beam specimens are carried out to illustrate and demonstrate the effectiveness of using asphalt mixtures with embedded piezoelectric smart aggregates for nondestructive ultrasonic monitoring.