A miniaturized early age concrete strengthening and hydration monitoring system based on piezoelectric transducer

Summarization: Structural integrity monitoring is an essential aspect in technical domain of structures safety, damage and collapse prevention. In case of concrete structures it is necessary this type of monitoring to be applied from the very early stages of construction, about a few hours after concrete casting, in order to perform an efficiently and reliable monitoring of concrete hardening and hydration physical procedure. In this paper, it is presented an integrated and miniaturized electromechanical impedance measuring system termed as T-WiEYE whose functionality is based to the dynamic interaction between piezoelectric materials (PZT) vibrations and concrete structure mechanical response. By applying a special mounting system consisting of a properly designed Teflon (PolyTetraFluoroEthylene) casing for PZT sensor/actuator, each T-WiEYE transducer should be bonded on the surfaces of fresh concrete specimens a few hours after their casting and, then, concrete hydration and strengthening procedure is monitored. Concrete curing physical process is monitored by acquiring electromechanical impedance response spectrums in a high frequency sweeping range for different elapsed from concrete casting times through a miniaturized integrated circuit board. At the same time a wireless connection between circuit-board and a client PC allows the direct transmission and storage of impedance measurement for further post-processing evaluation and real time structural integrity observation. Finally, our system is further evaluated, by monitoring any observed shifts in concrete early age hydration procedure, introducing a new early-age concrete strength gain index, termed as RMSD_R which incorporates the rates of changes in concrete strength during its hydration process.Παρουσιάστηκε στο: 10th HSTAM International Congress on Mechanic