Experimental Study On Acoustic Tomography Of Concrete Bridge Quality Detection

Acoustic tomography is mainly used to transmit sound waves inside objects,using a specific digital processing technology,it is transformed into an electrical signal that reproduces the internal properties of the object in the form of an image,it plays an important role in the detection project of concrete bridge.Acoustic tomography is a combination of geophysical exploration,digital computer and digital graphics,it was originally applied in the field of medicine,and has been widely applied in the field of engineering detection through further development,and has made remarkable achievements.The technique is not restricted by the length and width of the beam in the field of bridge detection,Moreover,the field operation is not complicated,and the accuracy of the test results is high,which is popular in the field of bridge nondestructive testing.The relationship between acoustic parameters of concrete such as wave length,wave speed,wave amplitude and frequency and the strength of concrete is introduced,the basic principle and method of acoustic tomography are described,the process,data collection and data processing of the technology are introduced briefly.Acoustic tomography was carried out on concrete members,It is concluded that l-shape layout is more advantageous than linear layout.The denser the excitation points are,the more accurate the test results will be.Acoustic tomography can detect long components.The selection of sampling time length is especially important to the size of detection component.In terms of concrete quality evaluation system,five parameters were selected as quantitative indicators of concrete quality evaluation,which were respectively ray density,ray orthogonality,average wave speed,wave speed dispersion and qualified rate area ratio,providing data processing basis for subsequent practical testing.The effect of concrete internal reinforcement,concrete age and asphalt layer on acoustic tomography is analyzed.Based on the quality evaluation system,the concrete test result representation method is developed,which is a comprehensive evaluation system composed of velocity distribution cloud map,velocity distribution histogram and strength distribution cloud map.The acoustic tomography technology is applied to the quality inspection of concrete bridge,and the density and strength distribution of concrete are analyzed.