Application of twin-plane ECT sensor for identification of the internal imperfections inside concrete beams

The main purpose of this paper is to investigate application of special construction of Electrical Capacitance Tomography (ECT) sensor to concrete beams internal homogeneity tests. Identification of internal imperfection inside the concrete beams is one of the main problems related to analysis of the construction structure bearing capacity. Therefore, this paper shows attempts to study the measurement prospects for this non-invasive, tomography based technique, in regard of concrete construction elements structure investigation. Presented results come from experiments with two types of internal inclusions, which cause the non-continuity at the concrete structure: soft and hard (of density lower, and higher, than this of pure concrete beam). The positions and dimensions of the imperfections were sensed with two non-invasive methods; ECT and, in order to verify the outcomes, X-ray tomography imaging. The range of application and the accuracy of both methods, in aspect of measurement of material concentration changes inside concrete beams, are discussed here. For the purpose of measurement results interpretation, in case of ECT only capacitance, unprocessed measurement data were analyzed, since such raw data processing do not introduce additional soft-field effect inverse problem solution errors.