Influence of hydration capacity for cement matrix on the piezoelectric properties and microstructure of cement-based piezoelectric ceramic composites

Cement-based piezoelectric ceramic composite (CPC) is the potential sensing element for long-term structural health monitoring due to its excellent durability and compatibility. In this study, the piezoelectric properties and microstructure of CPCs with the cement (fresh/hydrated cement powder) as matrix phase and lead zirconate titanate (PZT) particles utilized as functional phase are fabricated and characterized to investigate the effect of hydration capacity of the matrix on the piezoelectric properties. Piezoelectric properties testing and microstructure analysis are performed to evaluate the testing samples. Results show that the piezoelectric strain factor of the hydrated cement-based composite shows a decreasing trend with age, while that of the fresh cement-based composite shows an opposite tendency. The morphology and product structure of the composite after curing and polarization are tremendously different. After polarization, the calcium-silicate-hydrate (CSH) structure changes from fibrous to nano-ellipsoid. The interfacial transition zone of the fresh cement-based composite after curing and polarization is different from the hydrated cement-based composite due to the insufficient binding between CSH and PZT.