A PZT-Based Electromechanical Impedance Method for Monitoring the Soil Freeze–Thaw Process

Abstract

It is important to conduct research on the soil freeze–thaw process because concurrent adverse effects always occur during this process and can cause serious damage to engineering structures. In this paper, the variation of the impedance signature and the stress wave signal at different temperatures was monitored by using Lead Zirconate Titanate (PZT) transducers through the electromechanical impedance (EMI) method and the active sensing method. Three piezoceramic-based smart aggregates were used in this research. Among them, two smart aggregates were used for the active sensing method, through which one works as an actuator to emit the stress wave signal and the other one works as a sensor to receive the signal. In addition, another smart aggregate was employed for the EMI testing, in which it serves as both an actuator and a receiver to monitor the impedance signature. The trend of the impedance signature with variation of the temperature during the soil freeze–thaw process was obtained. Moreover, the relationship between the energy index of the stress wave signal and the soil temperature was established based on wavelet packet energy analysis. The results demonstrate that the piezoceramic-based electromechanical impedance method is reliable for monitoring the soil freezing and thawing process.

Monitoring of Epoxy-Grouted Bonding Strength Development between an Anchored Steel Bar and Concrete Using PZT-Enabled Active Sensing

“…Furthermore, because of its strong piezoelectric effect [40,41] and wide bandwidth [42,43,44], Lead Zirconate Titanate (PZT) is one of the most commonly used piezoceramic materials, and is frequently utilized for stress wave generation [45,46,47,48] and detection [49,50,51]. Stress waves are often used in structural health monitoring [52,53,54,55,56], especially in the active sensing method [57,58,59,60,61] and the electromechanical impedance method [62,63,64,65,66]. The active sensing method was used for monitoring bolt loosening [58], very early age cement hydration [59], a bolted spherical joint connection [60], and timber moisture [61].…”

“…The active sensing method was used for monitoring bolt loosening [58], very early age cement hydration [59], a bolted spherical joint connection [60], and timber moisture [61]. The impedance method was used for monitoring the damage in plate-like structures [62], bolted joint looseness [63], pin connection loosening [64], the freeze–thaw process in soil [65], and a concrete-filled fiber-reinforced polymer tube [66]. The PZT-enabled active sensing approach using surface-mounted or embedded transducers has shown great potential for the structural health monitoring of mechanical and civil structures in real time [67,68,69,70].…”

Effect of Pre-Corrosion Pits on Residual Fatigue Life for 42CrMo Steel

“…Therefore, the monitoring of corrosion pit size is important not only to know the corrosion status, but also to predict the residual fatigue life of the steel. With the recent development of structural health monitoring technology [41,42,43,44], especially the piezoceramic-based active sensing method [45,46,47], electromechanical impedance (EMI) approach [48,49,50], and imaging technology [51,52], it is now possible to monitor corrosion pit number and size [10]. Future work should include the real-time monitoring of the onset and growth of the corrosion pit and the prediction of the residual fatigue life of the 42CrMo steel specimens.…”

Design and Analysis of a Novel Piezoceramic Stack-based Smart Aggregate

“…After the detected signal is processed, the health state of the structure is evaluated, and early warnings are alerted if the structure is in danger. Recently, cracks under seismic and quasi-static load [ 43 , 44 , 45 ], concrete strength and water percentage in early age [ 46 , 47 , 48 ], impact and blast load [ 49 , 50 ], debonding or bond slip [ 51 , 52 ], leakage [ 53 ] and corrosion of the reinforced bar [ 54 ] in various types of concrete structures, including pipes [ 55 ], columns [ 56 , 57 ], beams [ 58 , 59 ] and piles [ 60 ] of concrete or reinforced concrete (RC), are detected or monitored with the help of SAs.…”