Application of capacitive techniques to investigate water transport and other durability indicators of cement-based materials: A review

Service life and durability of concrete structures have become one of the most concerning issues in civil engineering because of their economic and ecological implications. Most durability problems for concrete structures can be associated with the presence and migration of water. Capacitance measurements have been proven to be a powerful non-destructive testing technique for investigating water distribution in cement-based materials. Capacitance measurements are very sensitive to moisture because of the high contrast in relative permittivity between water and dried concrete. This review focuses on specific applications of capacitive techniques in studying the durability and degradation of cement-based materials. Examples of results obtained by qualitative and quantitative investigations of moisture content and water migration in such materials are given. Studies on using capacitive techniques for detecting chloride content, rebar corrosion, crack development and carbonation in concrete are discussed. Capacitance measurements are a feasible method for real-time and non-destructive testing of the durability of building materials. Current challenges and potential for further research in capacitive techniques are outlined and discussed. •Capacitance measurements are very sensitive to moisture in cement-based materials.•Capacitance measurements can detect moisture and chloride content, rebar corrosion, crack development and carbonation.•Calibration procedures are essential to achieve quantitative measurements.•Simultaneous detection of multiple media changes is a worthwhile research direction.