Validation of Electrical Conductivity Method to Assess Static Stability of SCC
Résumé
The objective of this study is to validate the electrical conductivity method used to assess stability of self-consolidating concrete (SCC) at early age. Various SCC mixtures made with a fixed water-to-cementitious materials ratio (w/cm) of 0.42, different aggregate gradations, and slump-flow values of 650 ± 10 and 700 ± 10 mm were evaluated. Analysis of changes in ionic concentrations along column sample with time provided adequate evaluation of stability of SCC. For example, the increase in the concentration of viscosity-modifying admixture from 1% to 2% was shown to decrease the homogeneity index from 0.36 to 0.27, reflecting better stability. Validation procedure was carried out by correlating stability indexes derived from electrical conductivity measurements to physical variations of coarse aggregate concentrations determined on plastic concrete sampled from the tested column elements at the end of electrical conductivity monitoring period. Good correlations between stability indexes and aggregate concentrations are established.