Nowadays, strength monitoring of concrete structures by the nondestructive method has gained more attention. Strength monitoring is not only important to determine the readiness of structures for service, but also to ensure the safety of the structure itself during the construction. The main goal of in-situ monitoring the strength gain in concrete is to obtain reliable information about the quality of concrete which can be further used to assess construction schedule and process of concrete structures, such as determining the optimal traffic opening time. The current methods are unreliable, inefficient, costly and partially destructive. To address these challenges, this paper aims to investigate the feasibility of employing polymer based piezoelectric sensors to characterize the in-situ compressive strength gain of concrete at the early ages. The pitch-catch approach was considered for the active sensing approach. In this approach, a piezoelectric transducer acts an actuator to propagates the Lamb waves while another piezoelectric device works as a sensor to detect the signal. A PVDF sensor was fabricated using electrospinning method, and a commercial PZT transducer was used to generate the Lamb waves. The developed piezoelectric-based set-up has shown a promising technique for strength development of cementitious materials at early ages.
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