Evaluation of the degree of degradation using the impact-echo method in civil engineering

Evaluation of the degree of degradation using the impact-echo method in civil engineering

Článek WoS

Non-destructive methods such as Impact-echo method are based on the acoustic properties of the material that are dependent on its condition. It allows the studied progress development of micro-defects in the structure of the material and is thus suitable for monitoring the building structure’s condition. This acoustic method allows us to identify and locate defects and is thus suitable for monitoring the building structure’s condition. The application of this method is widespread; it can be used in mechanical engineering, power engineering and in many industries as well as in the construction industry. Impact-echo uses a short-time mechanical impulse (a hammer blow) that is applied to a surface of the test sample and is detected by means of piezoelectric sensors placed on the surface of the sample. The impulse is reflected by the surface but also by micro-cracks and defects of the specimen that are under investigation. From thus obtained signal the frequency spectrum is determined and is found to be the dominant resonance frequency using fast Fourier transformations. The dominant frequencies give an account of the condition of the structure or determine the location of flaws, at which the waves are rebounded. The signal is digitized by means of a data processing system to be transferred into a computer memory. A piezoelectric MIDI sensor takes the signal response and it is brought to the input of an oscilloscope TiePie engineering Handyscope HS3 two-channel with 16-bit resolution. This paper reports the results of measurements by the Impact-echo method on three applications in civil engineering. The results are obtained in the laboratory during the hardening process in quasi-brittle materials such as alkali-activated slag mortars, the degradation of concrete samples by corrosion caused by the action of chlorides and the degradation of composite materials based on cement by high temperature.

Non-destructive methods such as Impact-echo method are based on the acoustic properties of the material that are dependent on its condition. It allows the studied progress development of micro-defects in the structure of the material and is thus suitable for monitoring the building structure’s condition. This acoustic method allows us to identify and locate defects and is thus suitable for monitoring the building structure’s condition. The application of this method is widespread; it can be used in mechanical engineering, power engineering and in many industries as well as in the construction industry. Impact-echo uses a short-time mechanical impulse (a hammer blow) that is applied to a surface of the test sample and is detected by means of piezoelectric sensors placed on the surface of the sample. The impulse is reflected by the surface but also by micro-cracks and defects of the specimen that are under investigation. From thus obtained signal the frequency spectrum is determined and is found to be the dominant resonance frequency using fast Fourier transformations. The dominant frequencies give an account of the condition of the structure or determine the location of flaws, at which the waves are rebounded. The signal is digitized by means of a data processing system to be transferred into a computer memory. A piezoelectric MIDI sensor takes the signal response and it is brought to the input of an oscilloscope TiePie engineering Handyscope HS3 two-channel with 16-bit resolution. This paper reports the results of measurements by the Impact-echo method on three applications in civil engineering. The results are obtained in the laboratory during the hardening process in quasi-brittle materials such as alkali-activated slag mortars, the degradation of concrete samples by corrosion caused by the action of chlorides and the degradation of composite materials based on cement by high temperature.

predominant frequency, high temperature, impact, mortar, specimens

predominant frequency, high temperature, impact, mortar, specimens

ŠTEFKOVÁ, D.; TIMČAKOVÁ, K.; TOPOLÁŘ, L.; CIKRLE, P.

2017

08.12.2016

Inštitut za kovinske materiale in tehnologije Ljubljana

Ljubljana

1580-2949

Materiali in Tehnologije

50

6

Slovinská republika

879

884

6

http://mit.imt.si/Revija/izvodi/mit166/stefkova.pdf