Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/43059
標題: Use of the normalized impact-echo spectrum to monitor the setting process of mortar
作者: Lin, S.K.
林宜清
Lin, Y.C.
Hsu, K.T.
Yen, T.
關鍵字: Stress wave
Impact-echo
Spectrum
Normalization
Mortar
Setting times
wave reflection method
concrete
strength
期刊/報告no:: Ndt & E International, Volume 43, Issue 5, Page(s) 385-393.
摘要: The objective of this paper is to introduce a newly developed nondestructive test technique called the normalized impact-echo spectrum and its application to monitoring the stiffening process of mortar. The impact-echo method is an effective and nondestructive technique for locating flaws in concrete. The depth of an air-concrete interface is determined by identifying the large amplitude peak in the spectrum at the dominant frequency corresponding to multiple wave reflections from the interface. However, the measure of the peak amplitude does not make sense because it changes with different impact forces. To make the peak amplitude meaningful, there is a need to normalize the spectrum on impact force. After normalization, the amplitudes in impact-echo spectra can provide useful information on the intensity of wave reflections at the interface. In this paper, the normalized impact-echo spectra were used to monitor the setting process of mortar. Experimental results demonstrate that the normalization of the impact-echo spectra can make the peak amplitude steady for various impacts and the coefficient of variation is less than 1.5%. The variation in the amplitude of the normalized impact-echo spectrum with the mortar age can indeed reflect the stiffening process of mortar. The results show that the proposed technique is suitable to monitor the setting process of mortar. (C) 2010 Elsevier Ltd. All rights reserved.
URI: http://hdl.handle.net/11455/43059
ISSN: 0963-8695
文章連結: http://dx.doi.org/10.1016/j.ndteint.2010.03.003
Appears in Collections:土木工程學系所

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