Evaluation on Structural Stiffness and Grouting Efficiency of Concrete Track Using Elastic Wave Tests

초록

In this research, the continuous resonance method was employed to evaluate the lateral variation in mortar-filling quality of precast concrete track. In the continuous resonance method, the amplitude of frequency response is measured using an instrumented hammer and an accelerometer is plotted against a pseudo-depth, which is half of the wave velocity divided by the frequency. The frequency response functions were measured at consecutive locations of measurement with 6-cm intervals, and combined together to generate a 2-D plot of frequency response. The sections with strong reflections or large amplitude of frequency response were found to be areas with high possibilities of internal voids and unfilled areas. The 2-D frequency response plot was efficient in locating possible areas of defect.