Non-destructive density-corrected estimation of the elastic modulus of slag-cement self-compacting concrete containing recycled aggregate

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.