Temperature-conductivity relationships for concrete : An activation energy approach

The application of electrical techniques for in situ durability monitoring of reinforced concrete structures is now receiving considerable attention. The electrical conductivity of concrete exposed to environmental action can assist in the assessment of the in-service performance of the concrete, likely deterioration rates for a particular exposure condition, or compliance with the specified design life. However, concrete exposed to the natural environment necessarily means that it will be subjected to extremes of temperature. As electrical conduction in concrete is primarily via mobile ions in the continuous interstitial aqueous phase, its measured electrical response will display a temperature dependence. When undertaking electrical measurements on concrete it is desirable to distinguish between changes in conductivity due to changing levels of pore saturation and/or ionic concentration and changes in conductivity due to fluctuations in ambient temperature. Concrete conductivity measurements can be standardized to an equivalent conductivity at a predefined reference temperature (e.g. 20 deg C) through the application of temperature correction formulae.