Theoretical and experimental study on the electrical resistivity method for evaluating fresh concrete segregation

Abstract

This paper aims to provide a theoretical foundation to support the application of the electrical resistivity method to in-situ monitoring segregation of fresh concrete. We proposed a new non-conducting sphere model and an electrical resistivity algorithm to study the correlation between the electrical resistivity and the volume fraction of coarse aggregates. Glass spheres with different sizes were used to replace coarse aggregates in validation experiments for neglecting the irregular surface of coarse aggregate particles. A modified rectangular column mold containing three pairs of electrodes at different heights was developed to evaluate the segregation of fresh concrete. The experimental results were also compared with those obtained by the conventional washing-sieving method. The applicability of the correlations between electrical resistivity values and volume fractions of coarse aggregates was confirmed. The segregation index obtained by the electrical resistivity method has a good linear correlation with the segregation coefficient obtained by the washing-sieving method. Therefore, the electrical resistivity method has a great potential for in-situ monitoring stability of fresh concrete during placement and compaction processes.