Damage Detection in Concrete Beams through Cement-based Piezoelectric Composites Polarized under Low Electric Fields

Abstract This study investigates the performance of Cement-based Piezoelectric Composites (CPCs) as embedded sensors for structural health monitoring of mortar beams. The CPCs are of the 0–3 types, fabricated by combining Lead Zirconate Titanate (PZT) powder and cement in a 1:1 volume ratio. Four sensor variants were produced through poling under low electric fields with varying intensities and durations: C1 (250 V/mm, 40 min), C2 (250 V/mm, 60 min), C3 (375 V/mm, 40 min), and C4 (375 V/mm, 60 min). These sensors were embedded in mortar beams and subjected to flexural loading while monitored using the Electromechanical Impedance (EMI) technique. The results revealed an observed pattern of conductance decrease with increasing load, due to ongoing microstructural changes. The use of the Root-Mean-Square Deviation (RMSD) index provided a quantitative assessment of the sensor responses for the rate of strength development and propagation of cracking. Despite the samples having similar electrical and mechanical properties, C4 was the only sensor to exhibit good reliability and stability in conductance, as well as a higher RMSD index value, indicating greater sensitivity. This shows that CPCs polarized with low electric fields have the potential to serve as effective self-sensing materials for damage detection and monitoring the structural integrity of larger elements, such as beams.