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 15.84M rayl. With decreasing composite thickness, the piezoelectric strain factor d(33), the dielectric factor epsilon(r), and dielectric loss tan delta of the composites decrease, while the piezoelectric voltage factor g(33), the thickness electromechanical coupling coefficient K(t), and the mechanical quality factor Q(m) increase. The acoustic impedance of the composites fluctuates around 14M 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.