In this paper, experimental results of the actuator effect of a 2-2 piezoelectric cement matrix composite are presented. A desirable actuator effect was observed in the composite. In the first part of this study, the actuator effect of the composite under free conditions was studied. It was found that the amplitude of the response increases, but the phase angle of the response decreases, both almost linearly with the frequency of the actuator effect. The second part of the study focused on the behavior of the actuator in a structure. Distinct differences were observed in the behaviors of the composite under free conditions and in a structural system (simulated by precompression in the frame of an MTS machine). Clearly, the behavior of the actuator in a structure is influenced by factors including the properties of other components of the structure and the interaction between the actuator and other components, which was represented here by the precompression level in the experiment. © 2002 Elsevier Science Ltd. All rights reserved.