Field monitoring of electrical conductivity of cover-zone concrete

A sensor system, developed in a previous laboratory study [McCarter WJ, Emerson M, Ezirim H. Properties of concrete in the cover-zone: developments in monitoring techniques. Mag Conc Res 1995;47(172):243-51; Chrisp TM, McCarter WJ, Starrs G, Basheer PAM, Blewett J. Depth related variation in conductivity to study wetting and drying of cover-zone concrete. Cem Conc Comp 2002;24(5):415-27], is used to obtain the spatial distribution of electrical conductivity within the cover-zone of concrete specimens subjected to a range of natural exposure conditions. The testing methodology enables in-situ monitoring of the electrical conductivity and technical issues relating to site measurements are discussed. The work also highlights the need for continual monitoring of the covercrete as the electrical conductivity changes with time, depth and environment.