engleski

Toward the better NDT characterization of cement and concrete/mortar in situ

There is an ever-growing need in practice to obtain more relevant information about the properties of the structure or particular structural element during construction or exploitation period. In this respect, NDT (non-destructive testing) methods, particularly ultrasonic NDT methods have great potential. In this work, special attention is given to the extraction of more information from the transient ultrasonic pulses recorded during the setting and hardening of the cement materials, identifying the wave packets of different polarizations and obtaining information about the development of mechanical properties of the tested object material. The hypothesis is the possibility of the description of the complex waveform recorded as a sequence of ultrasonic pulses each having the form: . Various ultrasonic probe arrangements and material compositions were studied, giving rise to the experimentally established proportionality between compressive strength of cement material and ultrasonic stress field. The possibility of long term in situ monitoring of the construction (material) properties i.e. changes due to the influence of harsh environment and periodic mechanical stresses has been discussed.

NDT; ultrasound; cement; wave packet; compressive strength

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