An Investigation Of Properties And ERT Based On Graphite Electrically Conductive Smart Concrete

In recent decades, as one of the most dynamic research fields in civil engineering disciplines, structural health monitoring(SHM) technology has proceeded apace, changed fast. Electrical Resistance Tomography(ERT) technology has a lot of advantages, such as nonintrusion, non-radioactivity, online, simpleness, inexpensiveness, which have been becoming research hotpots. The application of ERT in practical engineering is still in the research stage, due to the resistivity is very high and not steady, limiting its development. Graphite Electrically Conductive Smart Concrete(GECSC), which is a kind of cement containing a mount of graphite and has good capacity of perception and transformation between force and electricity, making it possible to be used in the concrete structure.However, the research is mostly focusing on the image reconstructed algorithm, this paper mainly studies on the concrete substrate which provides material basis for engineering structure health applications. This paper presents the structural performances as well as multi-functional characteristics, which mostly focuses on its electric conductivity. The main contents studied may be summarized as follows:⑴ Research on the mechanical properties of GECSC has been carried out. The basic mechanical properties of the modified material and the change rules of strength and flowability are obtained by carrying out the mechanical tests on concrete matrix mixed with graphite. Simultaneously, the influence of concrete structure property mixed with graphite is analyzed.⑵ The various factors on conductive properties of GECSC have been explored. In this experiment stainless steel net electrode is designed. It shows the relationship between the concrete electrical resistivity and the influencing factors, such as the dosage of graphite, curing age, moisture content and so on. The laws of measurement method and result have been studied under AC and DC power. The above results were analyzed theoretically to define the percolation values.⑶ A set of ERT system of GECSC has been proposed and designed. Based on PXI platform, with LBVIEW programming control, the virtual instrument is dedicated to improve the data measurement hardware system. Combined use of MATLAB and COMSOL, the software system of image reconstruction is carried out by scientific computing the measured data, perfusion into the finite element unit, providing the internal resistivity distribution of the matrix. This system provides a good platform for the research on ERT of GECSC structure.⑷ Experiments on ERT of GECSC structure has been conducted. The targets given with single and multi impurity are used for image simulation, and also research on the law of the GECSC imaging in different conductivity matrix. From these, we can determine resistivity threshold in the ERT system, and validate the detection accuracy of the model with defects.⑸ Finally, a comprehensive summary of this paper points out that the work needs to be done next, and makes corresponding prospects.