• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.347-348
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• 2010

Ultrasonic pulse velocity method is investigated to evaluate assessment on concrete properties without loss of structural function. In addition, a relatively simple, and economical, and high adaptability, and so the need is increasing. In this study, the load of the concrete historical conditions based on ultrasonic pulse velocity measurements to analyze the results of the internal defects of concrete was evaluated.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.209-216
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• 2014

One of the widely used NDT(Non-destructive techniques) is the ultrasonic pulse velocity (USPV) method, which determines the travel time of the ultrasonic pulse through the tested materials and most studies were focused on the results expressed in time domain. However, the signal of ultrasonic pulse in time domain can be transformed into frequency domain, through Fast fourier transform(FFT) to give more useful informations. This paper shows a comparison of changes in the pulse velocity and frequency domain signals of concrete for various load histories using lightweight fine aggregates. The strength prediction equation for normal concrete using USPV cannot be used to estimate lightweight fine aggregate concrete strength. The signals in frequency domain of ultrasonic pulse of lightweight fine aggregate concrete does not show any significant difference comparing with those of normal concrete. The increases in stress levels of concrete change the pulse velocities and maximum frequencies, however the apparent relationship between themselves can not be found in this experiment.