Smart aggregates (SAs) are often formed by embedding lead zirconate titanate (PZT) patches into concrete or marble blocks, which not only have the advantages of low cost, quick response, high reliability, and long service life, but also possess the comprehensive actuating and sensing abilities, and have been widely used in structural health monitoring in the field of civil engineering. However, due to the plate-like geometry of the PZT patch and the limited number of layers, the SAs have relatively short sensing range. To solve the problem of short sensing range, a new kind of smart aggregates using piezoelectric stacks was developed. Theoretical modeling of this new transducers was established, and three prototypes were fabricated. Comparisons between the theoretical predications and the experimental results were presented, and good agreements can be found. Effects of the key parameters, including the total height of specimen, the elastic modulus of cement, the radius of piezoelectric stack, the thickness of piezoelectric layer, and the number of piezoelectric layers in piezoelectric stack, on the electromechanical properties were analyzed, and the guidelines for optimal design were presented. In addition, the improved and the traditional SAs were used to monitoring the water content in the soil specimens based on the electromechanical impedance (EMI) technique. The results showed that the improved SAs using piezoelectric stacks is more sensitive than the traditional ones, which have promising potential in structural health monitoring in the field of civil engineering.