Acoustic emission wave velocity analysis of concrete with different aggregate particle size under graded loading
At present,when the acoustic emission technology is used to locate the damage of concrete structure,the fixed surface wave velocity is used to locate the damage.The influence of the acoustic emission signal of concrete transmitted from the inside of the concrete and the damage of concrete materials at different stages on the acoustic emission wave velocity is not considered,resulting in a certain de-viation between the test results and the actual situation.In this experiment,the damage of concrete is divided into five stages with three dif-ferent types of elastic wave velocity changes.The quantitative analysis of material damage is carried out by using the change of wave veloc-ity combined with the damage mechanics of classical materials.The experimental results show that when the water cement ratio is con-stant,the elastic wave velocity increases with the increase of concrete coarse aggregate particle size,but the upward trend of wave velocity decreases with the increase of particle size.With the increase of stress,the wave velocity decreases,and there is a certain linear relationship between the wave velocity and the stress stage.The positioning accuracy is closer to the actual damage location by using different wave ve-locities at different loading stages,which can effectively improve the positioning accuracy.The test results provide a new direction for non-destructive testing of concrete bridge structure and a reference value for its safety testing.
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