Monitoring Water and Ionic Penetration into Cover-Zone Concrete

Abstract

This paper presents the influence of cyclic wetting and drying on the absorption characteristics of cover-zone concrete. Portland cement concrete and concrete with partial replacement with fly ash and ground-granulated blast-furnace slag were used in the experimental program, with water and chloride solution applied at the suction surface. Electrical techniques were utilized in conjunction with a surface-applied, volumetric-gain method to study water and ionic movement. Monitoring the variation of electrical response across electrodes embedded within the cover region provided information on the depth and rate of water penetration, ionic ingress, and evidence of continuing hydration and pozzolanic activity. By combining depth-of-penetration data with the cumulative volumetric uptake of the samples, the effective porosity of the surface region could be estimated. Ponding studies were also undertaken on replicate samples to study ionic ingress.