Model Test Study On Detecting Grouting Defects In Prestressed Pipe By Ultrasonic Method

In recent years,China has invested heavily in infrastructure construction,along with the rapid development of highway construction projects,the bridge safety issues have attracted more and more attention,the duct grouting quality of prestressed bridge has become one of the focus of attention.quality of grouting Inadequate will lead to corrosion of prestressed steel strand,affect the stability and durability of the bridge,and become a security hazard.At present,the detection technology for grouting quality is not perfect,especially for double channel grouting quality detection needs to be supplemented.Based on the principle of ultrasonic wave,the attenuation characteristics of ultrasonic energy and frequency caused by viscous medium,aggregate particle size,cavity(void),prestressed tendon and different bellows are analyzed,The propagation law of ultrasonic wave in concrete beam,single pipe and double row pipe is studied by model beam test.The characteristic parameters of ultrasonic time,amplitude and wave velocity are obtained.The ultrasonic testing of double channel test beam with three rows of holes,full fullness,cavity fullness and cavity void,was carried out on the prestressed double row channel test beam,The influence of different test sequence,pipe material(PVC,iron sheet)on acoustic time,amplitude and wave velocity was studied,The grouting quality detection method of prestressed double row duct based on ultrasonic method is put forward,and the judgment standard of prestressed double row channel defect is established.The test data are processed scientifically by probability method,and the result is consistent with the location of prefabricated defect.The feasibility of combining ultrasonic testing with probability method to determine grouting quality of prestressed channel is verified.In this paper,the grouting quality of prestressed channel is studied by ultrasonic method,which provides the basis for accurate judgment of grouting quality and defect location of single row of channels,It is also extended to determine whether the double channel grouting is full or not,and provide reference for the quality supervision and control of prestressed bridges.