Non-Destructive Electrical Methods to Determine the Quality of Concrete

There is a great need to explore and develop non-destructive testing methods of concrete to ensure proper curing and it possesses required strength in construction and in service. Limited experiments using electrical methods have been reported in the literature to explore the relationship between the electrical properties and quality of concrete. This study was designed to develop experimental methods that employ the relationship between the electrical and mechanical properties of cement concrete. Concrete is an insulating material from the electrical point of view and large volume of theory and experimental techniques are available to study the insulating properties of materials used in electrical and electronic equipments. This study was oriented to examine whether those theories and experimental techniques, could be applied to concrete, with suitable modifications to its specific nature and properties. To facilitate this objective, several equivalent circuits were investigated to represent concrete as an insulating material. Simple measurement of resistivity alone has been undertaken by several previous investigators and it was felt, as confirmed by our own investigations, that this information is not sensitive enough. Therefore, a more sophisticated method based on fundamental electrical theory was developed. These experiments, conclusions drawn, proposal for a diagnostic method and possibility of future developments are discussed in this paper.