Non-destructive tests that cause no damage to concrete components can be used in rehabilitation works to
determine concrete mechanical properties, such as the modulus of elasticity. In this paper, models are presented
to predict the modulus of elasticity of Self-Compacting Concrete (SCC) with Recycled Aggregate (RA) and slag
cement through the hammer rebound index and ultrasonic pulse velocity. Simple- and multiple-regression
models were developed to estimate the modulus of elasticity according to the monotonic relation between
variables shown by Spearman correlations. In these models, the modulus of elasticity was always inversely
proportional to the square root of the non-destructive property under consideration, and the hardened density
raised to the power of 2.5 as correction factor always increased estimation accuracy and robustness. The
multiple-regression model with density correction yielded the most precise estimations of the elastic modulus
with deviations below ±10% and ±20% in 82% and 94% of cases, respectively.
