To study influences of material and structural parameters of RC slabs on wave velocity and amplitude attenuation of acoustic emission (AE), pencil lead breaks (PLB) and AE tests of 9 RC slab specimens were conducted.Using a self-made PLB device for PLB tests, the AE detecting parameters including threshold, peak identification time, identification of impact time, and impact locking time being applicable to RC slabs were determined.Through PLB and AE tests, the influence laws of RC age, thickness, concrete strength grade, coarse aggregate maximum particle size and reinforcement on AE wave velocity and amplitude attenuation were studied.The results showed that thickness and concrete strength grade are important factors to affect AE wave velocity and amplitude attenuation; AE wave velocity decreases with increase in concrete thickness, and it increases with increase in concrete strength grade; the larger the thickness and the lower the concrete strength grade, the bigger the amplitude attenuation; coarse aggregate maximum particle size and reinforcement ratio affect AE amplitude attenuation and wave velocity more weakly; the relation expression between amplitude attenuation value and propagation distance is derived, and the threshold value for amplitude attenuation is recommended.
Key words
Reinforced concrete slab /
nondestructive testing /
acoustic emission /
velocity /
amplitude attenuation
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