INFLUENCES OF RESIDUAL DUST IN POST-INSTALLED ADHESIVE ANCHOR HOLES ON VIBRATION BEHAVIOR OF BONDED PORTIONS EVALUATED BY ELECTROMAGNETIC PULSE METHOD

摘要

In this study, regarding electromagnetic pulse method, the influences of the residual dust of anchor hole before filling adhesive on the evaluation value were examined. The method uses ring shaped exciting coils and large pulse current for generating steep magnetic field around the coil. Thus, the magnetic field gives impact force to the anchor, which causes vibration of the anchor. Under different conditions of clearing holes of specimens, such as blow-out or brushing, the vibration behavior of bonded portions around the anchor were measured. The first measuring point was the bolt head and the second was the concrete surface near to the anchor. As the evaluation value of the vibration behavior, wave energy of received signal was defined as a square sum of measured data. After the measurements of them, pull-out test was conducted. As a result, it was found that the existence of the residual dust in the anchor hole changed the wave energy and reduced the pull-out strength. And, it was also found that the wave energy on the bolt head increased when the pull-out strength was lost.