The Influence of Slag/Fly Ash Ratio and Sodium Silicate Modulus on the Properties of 1-3-2 Alkali-Based Piezoelectric Composite

In this paper, a comprehensive experimental investigation on the effect of the slag-to-fly ash ratio (hereafter referred to as SL/FA) and sodium silicate modulus on the properties of a 1-3-2 piezoelectric composite was carried out. The influence of the SL/FA ratio on various properties was initially investigated. Compared with other specimens, specimens with SL/FA = 40%:60% had the highest electromechanical coupling coefficient (Kt = 77.67%, Kp = 71%). Therefore, the specimen with SL/FA = 40%:60% was chosen to explore the effect of the sodium silicate modulus. Additionally, the specimen with SL/FA = 40%:60% and a sodium silicate modulus of 1.3 had the best electromechanical conversion efficiency with Kt = 75.68% and Kp = 75.95%. The 1-3-2 alkali-based piezoelectric composite proved to have the characteristics of a low cost, optimal piezoelectric and mechanical properties, higher tunability, and better compatibility with concrete. It is a potential alternative to cement-based piezoelectric composites and may be widely utilized to monitor the health of concrete structures.