Capacitance-based compression self-sensing effectiveness of cement paste with curing time

Abstract

In this study, capacitance based self-sensing properties of the cement pastes of different curing time are studied for the first time. 7-day, 14-day and 28-day cement paste samples which do not require any functional materials are tested. Continuous and discontinuous loading cycles (minimum load of 21 kPa, maximum load of 98 kPa) are applied to the cement pastes. It is revealed that capacitance based self-sensing is superior to resistance based self-sensing owing to its greater dependence on stress and reversibility. The capacitance change is irreversible for the 7-day cement paste sample due to irreversible deformation. Over time capacitive self-sensing become more effective. The stress sensitivity (fractional increase in capacitance divided by stress) for the 28-day cement paste sample is 2.54 x10−8/Pa. It is also revealed that with an increase in hydration time, decreases in capacitance values are observed, which shows that the strength increase in cement paste can also be sensed with capacitance measurement.