Non-destructive evaluation of cracks in massive concrete using normal dc resistivity logging

Discontinuities are one of the most harmful damage to the durability of concrete structures. Currents approaches are limited to assessments of surface damages, even if non-destructive methods appear to be effective for the detection and the location of cracks. That is why, these methods might be unsuitable for investigation of massive concrete body as dams and locks. Present works aim at the presentation of new results with electrical resistivity to study damages within concrete structures. In this article, the electrical resistivity focused on the study of cracks and discontinuities (concrete joints, interfaces…) in massive concrete structures by measurements done in preexisting boreholes. The used array is the normal dc resistivity logging. The study presents numerical and experimental results. First, modeling allows correcting experimental data. Then, development shows the sensitivity relatively to the discontinuity characteristics (aperture and the resistivity contrast between the discontinuity and the concrete). The tests on a real structure are carried out to define the methodology for on-site measurement. Results support the modeling.