Technical Diagnostics and Non-Destructive Testing, №1, 2017 pp. 5-10
Magnetic method for determination of the thickness of protective concrete layer and diameter of rebars of building structures
Gusev A. P., Shukevich Ya. I., Lukianov A. L.
Institute of Applied Physics of the National Academy of
Sciences of Belarus. 220072, Minsk, str. Academic, 16.
A magnetic method of determination of the thickness of protective concrete layer and diameter of rebars of concrete building structures is proposed. Computer modeling was used to obtain the distribution of magnetization in a steel rod, and distribution of intensity of magnetic scattering field of the rod at local magnetization by a constant magnet field, depending on rod diameter and its distance to the magnet, was experimentally studied. It is shown that the longitudinal component of rod magnetization, which is characterized by coaxial oppositely directed dipoles, makes a prevailing contribution into the rod scattering field at small dimensions of the magnet. The proposed method is based on measurement of intensity of the rod scattering magnetic field simultaneously in two points above the controlled object surface in the zone of rod magnetization and application of a calibration grid, plotted by the dependencies of the rod scattering field on two determined parameters. A procedure of plotting a calibration grid of measuring instrument for monitoring concrete building structures is shown. 12 References, 2 Tables, 4 Figures.
Keywords: magnetic control method, protective layer of concrete, rebar diameter
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