Integrated ultrasonic sensors for robust structural health monitoring of concrete structures

Concrete is the most widely used structural material in modern civil engineering, and its internal integrity is closely related to public safety and service life. Ultrasonic nondestructive testing is essential for concrete structural health monitoring, where acoustic transmission, anti-interference capability, and signal quality strongly affect detection accuracy. To overcome the insufficient integration of acoustic impedance matching, electromagnetic shielding, and signal conditioning in existing embedded piezoelectric ultrasonic sensors, this study develops an integrated ultrasonic sensor based on a previously proposed acoustic matched smart aggregate, incorporating an electromagnetic shielding structure and an on-board preamplifier circuit. By jointly optimizing acoustic transmission, electromagnetic compatibility, and front-end signal conditioning, the sensor improves signal quality and robustness in concrete environments. Experiments demonstrate enhanced signal reception, stable anti-interference performance, and a significantly improved signal-to-noise ratio. Ultrasonic CT imaging further confirms its ability to identify internal defects in concrete, supporting its application in concrete inspection and structural health monitoring.