Enhancing capacitive self-sensing ability of cement mortar by designing electrode configuration

Abstract

Capacitance-based measurement, which enables self-sensing without the need for any conductive additives, is very advantageous for the construction and building sector as it can be applied both in existing and newly constructed structures. In this study, the most effective electrode configuration has been investigated to detect the most effective self-sensing ability. Capacitive self-sensing measurements were conducted in a 10.3-kPa to 41.2-kPa stress regime during loading and subsequent unloading at progressively increasing stress levels. Aluminum foil acting as the electrode was attached to the mortar plate using dielectric film. The capacitance was measured by an LCR meter. The most effective configuration for self-sensing was determined by varying the area of the coplanar electrodes and the distances between them. The sensing effectiveness increased with decreasing electrode width, such that the highest effectiveness was obtained when the width was 1.5 cm. Moreover, the effectiveness increased with decreasing inter-electrode distance, such that the highest effectiveness was obtained when the distance is 10 cm. With the optimum electrode design, the highest sensing effectiveness of 4.4% was reached. So, the most effective capacitive self-sensing is achieved by positioning the electrodes closest to the area where the load is applied and keeping the electrode area low.