Mechanical Characterization of Concrete by Impact Acoustics Tests

Abstract

The impact acoustic test is a fast and low-cost nondestructive alternative to evaluate the mechanical properties of concrete. However, the dynamic elastic modulus obtained in this test differs systematically from the static one. The aim of this paper is to study this relationship as well as to identify possible advantages and limitations of impact acoustics in comparison to compression tests until the age of 28 days. Seventeen concrete mixtures were prepared, obtaining compressive strengths ranging from 13 to 147 MPa. Acoustic and compression tests were performed at different ages (typically 3, 7, 14, and 28 days). The results obtained from impact acoustics showed lower dispersion [average coefficient of variation (CV)=1.53%], better representation of maturity over time (R2=.75), and excellent correlation to compressive strength (R2=.88) and static elastic modulus (R2=.75). This technique has the potential of application to evaluate the evolution of the mechanical properties of concrete over time in the prestress concrete industry.