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Please use this identifier to cite or link to this item: http://hdl.handle.net/1783.1/3387
Title: Contactless, transformer-based measurement of the resistivity of materials
Authors: Li, Zhongjin
Li, Wenlai
Keywords: Resistivity measurement
Material properties
Cement-based materials
Issue Date: 28-Oct-2003
Citation: US Patent 6,639,401 B2, 2003
Abstract: Traditional methods for resistivity measurements of concrete have to use two plate electrodes at opposite sides of a prism specimen. The major drawback of such a method is that the electrodes can be easily detached from the specimen due to shrinkage of concrete. Thus the measurement of resistivity is not accurate and sometimes easily has an unacceptable error. To get accurate measurement of resistivity of cement-based materials, a new device is invented. The new device utilizes a toroidal current principle. The concrete to be measured is case into a ring shape specimen and acts as the secondary of a transformer. A formulae to provide accurate resistivity of concrete has been developed according to the relationship between the toroidal current, the toroidal voltage and the phase difference between them.
Rights: This patent is also available at HKUST Technology Transfer Center Patent Search at <http://patentsearch.ttc.ust.hk/ListPatentsDetail.asp?id=162>
URI: http://hdl.handle.net/1783.1/3387
Appears in Collections:CIVL Patents

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