Temperature Effect on Electrical Resistivity Measurements on Mature Saturated Concrete

The electrical resistivity is an important parameter currently used to characterize the durability of reinforced concrete. Concrete resistivity measurements have been correlated to the corrosion rate of depassivated steel reinforcements and to the chloride penetration resistance of concrete. The resistivity of concrete is influenced by a number of factors such as pore structure, ion composition in pore water, cement content and degree of saturation. Concrete resistivity is temperature dependent and thus an increase in temperature leads to a decrease in resistivity. An investigation was carried out to study the influence of temperature on resistivity measured on mature saturated high performance concrete cylinders (fully hydrated or close-to). Measurements were performed on 10 cm diameter ×20 cm concrete cylinders under temperatures ranging from 10°C to 45°C. Results show that temperature has different effects depending on the intrinsic resistivity of concrete. It is concluded that an accurate method can be developed to normalize concrete resistivity measured at different temperatures and converted these resistivity values to a reference temperature.