Influence of mortar strength grade on acoustic emission signal parameter characteristics
Acoustic emission technology was used to conduct lead breaking test on mortar of different strength levels speciments.The influence of different strength levels on positioning accuracy,sound velocity calibration and time parameter setting of mortar detected by acoustic emission was investigated.The results show that intensity level is one of the main factors affecting acoustic emission detection parameters.The strength grade of mortar is controlled by water cement ratio in the test.The higher the strength grade of mortar,the greater the elastic wave velocity.The wave velocity of M10 and M15 mortar specimens increased by 5.2％and 8.9％respectively compared with M5,and the rise time decreased by 10.7％and 14.6％respectively,and the maximum rise time was within 150 µs.Peak Definition Time(PDT),Hit Definition Time(HDT)and Hit Lockout Time(HLT)can be set to 150 μs,300 µs and 400 µs respectively.There is a certain relationship between the sensor layout and the damage location accuracy,and it needs to be optimized before the test.With the increase of mortar strength grade,the attenuation of acoustic emission amplitude signal increases.
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