THE BEHAVIOR OF ULTRASONIC WAVES PROPAGATING IN CONCRETE USING THE ULTRASONIC-PULSE METHODS TO MEASURE THE DEPTHS OF CRACKS IN CONCRETE

摘要

With a system of two sensitive accelerometers connected to a high-resolution of oscilloscope, the paper proposed an arrangement of accelerometers to monitor the pulse waves generated by an ultrasonic transducer when performing a surface measurement on concrete. The velocities of the logitudinal wave (the P-wave) and the Rayleigh wave (the R-wave) were estimated by reading the responses of the wave in time domain. The results were in a good agreement with the estimated P-wave velocity by a direct measurement using the ultrasonic apparatus. A similar arrangement was performed on concrete cracks to predicted the depths. The results were very close to the actual depths with errors well within ±1 cm.