Acoustic emission testing method for the sleeve grouting compactness of fabricated structure

The sleeve grouting compactness of a fabricated structure directly affects its quality and safety, which are important. In this study, an acoustic emission system composed of an acoustic emission instrument and signal generator is used to test the preliminary detection of sleeve grouting connection compactness via a reasonable test method. The acoustic emission characteristics of prefabricated components under the excitation of signal generator are collected, and the characteristics of acoustic emission signals under different concrete strength, hollow sleeve positions, and compactness cases are analyzed. Results show that the amplitude of 00 concrete (66.63-66.86 dB) is higher than that of C40 concrete (56.96-57.54 dB). For the C40 specimen, the amplitude of the hollow sleeve is between 53.77 dB and 54.55 dB, which is lower than that of concrete. The amplitude of the compacting sleeve is between 67.61 dB and 67.86 dB, which is higher than that of the hollow sleeve. The amplitude of the compacting sleeve after adding reinforcement is between 59.98 dB and 60.37 dB, which are lower than that before adding reinforcement. The characteristic amplitude and energy of the acoustic emission signal are distributed obviously under the abovementioned working conditions. Wavelet analysis for the received acoustic waveforms was performed by the Continuous Wavelet Transform. The results show that there are some differences among the wavelet signals. Hence, the sleeve grouting connection compactness of fabricated structure can be detected on the basis of acoustic emission technology. (C) 2019 Elsevier Ltd. All rights reserved.