A novel electromechanical impedance resonance method for measuring elastic constants of very-early-age concrete cubes

Abstract

Measuring early-age properties of concrete is an essential yet challenging task. Traditional dynamic resonance methods cannot measure very-early-age elastic constants of concrete because sensors cannot be installed before demolding. The existing electromechanical impedance (EMI) technique in the literature, considered an emerging type of resonance method, can typically work only after the initial setting of concrete. The high damping ratios and dramatic changes in Poisson’s ratio of concrete at very-early ages challenge mode identification and evaluation accuracy of the existing EMI techniques. To address this research gap, this study presents a novel EMI technique to measure the elastic constants of very-early-age concrete cubes using embedded piezoelectric patches. Numerical investigations were conducted first to explore sensor installation strategies and establish evaluation procedures. Experiments were subsequently conducted to validate the effectiveness and accuracy of the proposed EMI technique by comparing it with standard dynamic and static methods. Continuous monitoring tests showed that the proposed method could measure the elastic constants of concrete as early as 2 h after casting, which the traditional dynamic and EMI methods could hardly achieve.