Quantification and uncertainty analysis of a structural monitoring device: detection of chloride in concrete using DC electrical resistivity measurement

摘要

In this work, we seek to assess and optimise the performance of an integrated chloride detection sensor based on the DC electrical resistivity measurement. We specifically seek to evaluate the detection threshold of chlorides. The main problem of the resistivity measurements in concrete is the dispersion of results mainly linked to the material heterogeneity and electrical contact limitations. To take into account the uncertainty of the measurement, we used a measurement device and sensors based on Geoelectrical Imaging methods. It gives richer information than the one delivered by conventional resistivity measurement sensors. Thus, it allows the use of statistical analysis and quality assessment methods. Before performing tests in concrete, we worked in a medium of known and homogenous resistivity in order to assess and optimise the performances of the acquisition system. Then we performed tests on concrete specimens containing different contents of chloride ions. Performance assessment of the resistivity probe is based on an analysis of receiver operating characteristic curves and the detection threshold of chlorides is calculated using the alpha delta method.