An approach for characterising electrical conductivity of cement-admixed clays

Abstract

This paper proposes a framework for relating electrical conductivity of cement-treated marine clay to its strength. The feasibility of relating conductivity to strength is first examined by measuring the two quantities over a range of water-cement and soil-cement ratios as well as curing periods. The results indicate that, within a limited curing period, conductivity changes are sufficiently monotonic to permit its correlation to strength. This leads to the proposal of two empirical relationships, which relate the strength and conductivity to the water-cement and soil-cement ratios of the treated soil. By assuming that there is no diffusion of water from the binder during the relatively short mixing duration, the water-cement and soil-cement ratios can be related to the in-situ water content, water-cement ratio of the binder and the binder mass fraction. If the first two quantities are constant over the site and only the last quantity is a variable, then the conductivity can be uniquely related to the strength. This provides the framework for correlating strength and conductivity measurements, which would allow electrical resistivity measurements to be used to infill point strength data from core samples for quality control of cement-treatment works.

Keywords

• Cement-admixed clay
• Unconfined compressive strength
• Electrical resistivity