Acoustic Emission Characteristics of Normal and Layered Concrete Blocks during Dilating/Static Fracture

Figure 4

Schematic diagram of the experimental system. I (acoustic emission acquisition unit): (1) desktop computer (signal display) and (2) AE system (8 channels); II (acoustic emission preamplifiers unit): (3) AE preamplifiers (20/40/60 dB); III (monitoring unit of concrete structures and AE sensors): (4) AE sensors (frequency range: 50–400 kHz, center frequency: 150 kHz) and (5) concrete blocks; IV (micrometer unit): (6) micrometers, (7) fixed support, and (8) data acquisition instrument.