Detection experiment on the impact-echo equivalent velocity method for quality ofgrouting-anchor connections in prefabricated building

Experimental studies on the grouting quality of the grouted and splicing joints in precast concrete buildings were undertaken based on the impact-echo equivalent velocity (IEEV)method. The test results show that through the maximum entropy method (MEM), the signals are converted into a thickness image. IEEV can accurately identify whether the corrugated pipe is grouted and it can identify the 50,100 mm small defects embedded in different diameter pipes; However, it is impossible to identify the existence of steel bar in corrugated bar, and spiral hoop, sandwich insulation layer and double row of corrugated pipes will result in the failure to identify the quality of grouting-anchor connection.