Investigating piezoelectric sensor performance for crack detection in concrete pavements

Crack detection in concrete pavements is crucial for ensuring their structural integrity, safety, and longevity, as undetected cracks can lead to severe deterioration and costly repairs. This study investigates the effectiveness of piezoelectric sensors embedded in concrete beams for crack detection under cyclic and fatigue loading, with a focus on their application in pavement health assessment. Employing lead zirconate titanate (PZT) ceramic sensors sealed with Polydimethylsiloxane (PDMS), four-point bending and cyclic loading tests were conducted using 30-mm and 12-mm sensors. Embedding a 30-mm sensor reduced the flexural strength of the concrete by approximately 9%, whereas the 12-mm sensor had no adverse effect, preserving the original strength of 5.6 ± 0.4 MPa. Under cyclic loading, the 12-mm sensor produced a clear and reliable response with peak-to-peak voltages increasing from 0.1 mV at 0.5 kN/s to 0.3 mV at 2 kN/s, while the 30-mm sensor, despite higher output, exhibited noisier signals requiring filtration. Fatigue experiments demonstrated that the sensors could detect microcrack initiation 7–8 cycles before visible failure, providing an early warning of impending damage. Sensor placement tests confirmed that although voltage output decreased with distance from the crack, detection remained possible even near the supports. Analytical and finite-element modeling further indicated that normal stress predominantly governs sensor response, in close agreement with experimental findings. These quantitative results establish piezoelectric sensors as a practical, cost-effective technology for early crack detection and proactive pavement maintenance.