Application Study On Damage Detection In Concrete Using Electrical Tomography

Electrical tomography is an imaging technique for nondestructive testing. Due to the advantages of non invasive(lossless), low price, fast response speed, no radiation and detection results directly, in the field of measurement of multiphase flow, medicine, flame detection, permafrost monitoring has been good application. But the electrical tomography technology is rarely reported in the damage detection of concrete structures.Electrical tomography technology is applied to the damage detection of concrete structures. By applying current excitation to concrete, the boundary value of the conductivity distribution of concrete is collected by the data acquisition system, and the internal structure of the concrete is imaged by the image reconstruction algorithm. The main innovatory work are listed as follow:1. The data acquisition system of electrical tomography is developed and designed. The system is based on the PXI platform of Ni company development and production, and the use of language LabVIEW data acquisition control program is written. This system can be in guarantee high sampling accuracy at the same time, the simple realization of switching the excitation electrode and boundary sampling voltage. At the same time, the reconstructed image data into the computer.2. The electrical tomography reconstruction algorithm were studied through simulation experiment and discussed the quality of five kinds of image reconstruction algorithm, and ultimately selected the improved normalized image reconstruction algorithm. Moreover,based on Matlab GUI platform written electrical tomography system interface, convenient in data management and image reconstruction.This paper takes the water body as the object to carry out the imaging experiment. To verify the feasibility of the design of data acquisition system. The experimental results show that the electrical tomography system design is suitable.3. Electrical tomography system is set up, and the feasibility of this imaging system is discussed by using the water body as the object. The experimental results show that the electrical tomography system is suitable for the system.4. Through the electrical tomography system built for the damage detection of concretestructure, first of all to achieve the on(aperture) imaging to monitor the damage in concrete structure followed by the detection of rebar in concrete, including corrosion before and after corrosion imaging monitoring, the final realization of concrete in seawater penetration and diffusion imaging monitoring.