Evaluation of the elastic modulus of concrete using non-destructive ultrasonic methods and the natural vibration method

The compressive strength of concrete is one of the main indicators of structural safety, quality, and durability. However, for designers, the modulus of elasticity is equally essential during the structural modelling phase, as it directly influences the behaviour of the material under load. In this study, the dynamic modulus of elasticity was obtained and evaluated by means of the ultrasound method, and compared with the results obtained by the excitation method using the Sonelastic® system. A set of 48 cylindrical concrete samples with different strengths was used, allowing comparisons between the acoustic methods in different strength classes. The data were essential to validate the dynamic modulus estimates and verify their compatibility with the normative values. Based on these parameters, measurements were monitored at 14 and 28 days, the latter being considered as a reference. The measurements facilitated comparisons between the acoustic methods selected for estimating the dynamic modulus of elasticity, as well as comparisons with the static modulus of elasticity results established by the ABNT NBR 6118:2023 standard. The evaluation of metrological performance was carried out using standardized errors, which verified the compatibility of the results obtained with the normative methods.