For the estimation method of crack depths in concrete by using ultrasonic techniques, the influ- ence of micro-cracks around macro-crack tips on the propagation of ultrasonic pulses has not been clarified. In this study, crack depths in concrete beam specimens…
For the estimation method of crack depths in concrete by using ultrasonic techniques, the influ- ence of micro-cracks around macro-crack tips on the propagation of ultrasonic pulses has not been clarified. In this study, crack depths in concrete beam specimens under bending loading were estimated through the ul- trasonic method (ultrasonic crack depth), and were compared with the measured crack depth after dyeing. In addition, crack depths were determined by finite element analysis with the tension softening diagram, and the results were compared to those obtained through the ultrasonic method. Finally, the influence of fracture pro- cess zone(FPZ) on the evaluation of the ultrasonic crack depth was studied. As the results, the Ultrasonic Crack Depth is strongly affected by the micro cracks in FPZ, hence, it is important to consider the influence of FPZ when evaluating crack depth.