コンクリート内部の弾性波動伝播特性に関する基礎的研究

Abstract

In this study, the elastic wave method was applied for estimating the location of inclusion such as void and steel plate, as the fundamental investigation to establish a new non-destructive testing technique for concrete. In the experiments, plate specimens of dimension 30×30×10cm were used. In the analysis, a 2-dimensional finite element method was used to solve the equations of elastic waves for concrete plates with inclusion such as void and steel plate and the wave propagation analyses and the frequency response analyses were carried out. Following results were obtained in this study : 1) The location of void and steel plate can be most accurately estimated by using a resonance technique among techniques applied in this experiments (resonance technique and flection technique). 2) In the reflection technique, it is necessary to set two transducers to keep the angle from the top of inclusion at the best reflectionangle, so as to improve the accuracy for estimating its location. 3) The accuracy of location estimation can be raised by combining the result of frequency analysis of measured waveform. 4) The inclusion location in concrete can be predicted exactly from the frequency characteristics, when the reflection wave is clearly detected.