A Detection System Of Concrete Resistivity

In the field of civil engineering, concrete is a very important structural material, its quality is directly related to the security the of engineering construction, thereby affecting people’s lives and property safety, the correct and reasonable concrete detection means has a very important research value and practical significance for the safety and specifications of the concrete engineering. In recent years, as people continue to study the electrochemical theory of concrete, it was found that the concrete resistivity has a very close relationship with changes in the internal structure of the concrete. Through concrete resistivity analysis, we can determine defect and damage in concrete structures. Concrete resistivity measurement is simple, fast, easy to operate, in order to opened up a new direction for concrete test engineering.In this paper, through research and analysis of concrete electrochemical theory, combining with the measuring principle and measuring methods of high density resistivity detection method, regarding the microprocessor as a control core, we devised a concrete resistivity automatic detection system based on the high density electrical resistivity detection method. The system can automatically collect multiple locations and distances of concrete impedance signal, recuperate and analyze collected concrete impedance signal, and calculated resistivity values of the concrete. The measured resistivity data is input to the concrete resistivity tomography imaging software to analyze, inferring defect and damage in internal structure of the concrete situation by tomography. The system not only can quickly detect the quality of the concrete, but also real-time measurement, and forecast track. The main contents of this paper are as follows:1、Theoretical analysis of the system and scheme selection. First, the paper verify the feasibility of concrete resistivity testing concrete by electrochemically theoretical analysis of the concrete. Secondly, through the high density resistivity method detection principle and method analysis, We put forward automatic concrete testing system based on high density resistivity method, regarding the microprocessor as a control core.2、The hardware circuit and software design of the system.The system regard the microcontroller as a main control core and control each other module of the system, to ensure the normal and orderly operation of the entire system. The hardware circuit of the system conludes a main controller stm32f103C8T6, power supply circuit, signal acquiring-measuring channel switching circuit, DDS signal generator, the circuit based on bridge balance principle, the signal buffer amplifier circuit, phase-sensitive detector, AD conversion module,485 communication module and so on. The software design of system includes automatic range selection and gain automatic selection in impedance measurement process, acquiring-measuring channel switching automatically and orderly in the signal acquisition process, AD collection, data communication transmission and so on.3-. System verification. The concrete resistivity detection system designed in the paper measures defective concrete created by us through high density resistivity measurement. Then the experimental data measured is input to the high-density resistivity imaging software for tomographic analysis, inferred defect characteristics and damage inside the concrete situation through tomography. Finally, the inference result can verify the feasibility and accuracy of the system compared with the actual defective concrete sample.