P-Wave Arrival Determination and AE Characterization of Concrete

The arrival time of the first P-wave is, among other parameters, of prime importance for pinpointing the location of an acoustic emission (AE) event source. However, it seems that determining the first P-wave arrival times from digitized signals has been overlooked in previous works. In this paper, a new method is proposed based on digital signal processing techniques. AE analyses are then performed for both normal-strength concrete and high-strength concrete in uniaxial tension to study the damage initiation and progression by interpreting the activities and locations of AE events. The results indicate that using the proposed method to determine the P-wave arrival time of AE signals is quite successful. It is found that microcracking starts early before peak stress. Localization is clearly observed for both normal-strength concrete and high-strength concrete. The examination of AE activities and source location maps reveal that the internal microcracking behavior is consistent with the macroscopic deformation behavior of the materials.