Joint measurement of modulus of elasticity and poisson’s ratio of concrete cubes by actuating special vibration modes : a novel baseline-free technique

Abstract

Elastic constants (e.g., modulus of elasticity and Poisson's ratio) of concrete are vital material properties commonly measured by standard static tests (such as the destructive tests of cylinders or prisms), but the corresponding measurement results usually present a large dispersion. In addition, though extensively applied to measure modulus of elasticity, traditional dynamic methods cannot stably measure Poisson's ratio of concrete, because of their sensitivity to material anisotropy and wall effects of concrete. To overcome these deficiencies, this paper, for the first time, presents a highly accurate method for directly measuring the elastic constants of concrete cubes with high stability using an improved baseline-free electromechanical impedance technique. With the ability of piezoelectric sensors to effectively capture a series of vibration modes of a concrete cube, unique modes can be identified, actuated, and employed for measurement. In this study, a series of numerical analyses were conducted firstly to (a) search anisotropy-insensitive vibration modes of a cube, (b) design corresponding sensor installation strategies for target modes extraction, (c) establish the quantitative evaluation methods, and (d) examine the reliability of the proposed method by considering anisotropy and wall effects. Then, experiments on concrete cubes were performed to show the high accuracy, stability, and reproducibility of the proposed method by comparing it with traditional standard static and dynamic methods.