Effect of cement matrix and composite thickness on properties of 2-2 type cement-based piezoelectric composites

In this study, 2-2 type cement-based piezoelectric composites were fabricated by dice-and-fill technique. The effects of cement matrix and composite thickness on electrical and acoustic properties of the composite were analyzed. The results show that all the 2-2 type cement-based piezoelectric composites using different kinds of cement as matrix have superior piezoelectric and electromechanical properties. Cement matrix has little influence on the acoustic impedance of the composites, which fluctuates between 13.68 and 15.84 M rayl. With decreasing composite thickness, the piezoelectric strain factor d₃₃, the dielectric factor ε_ρ, and dielectric loss tan δ of the composites decrease, while the piezoelectric voltage factor g₃₃, the thickness electromechanical coupling coefficient K_t, and the mechanical quality factor Q_m increase. The acoustic impedance of the composites fluctuates around 14 M rayl with increasing the composite thickness, which is obviously less than that of the pure piezoelectric ceramic. Therefore, 2-2 type cement-based piezoelectric sensors suitable for civil engineering structure can be easily tailored by adjusting the composite thickness.