On the Assessment of Actual Compressive Strength of Concrete in Reinforced Columns: Influence of Core Diameter and Slenderness Ratio

This paper studies the influence of core diameters and slenderness ratio on the assessment of the actual compressive strength of concrete on reinforced-concrete elements. The experiment consists of the preparation of three reinforced concrete columns and the extraction of cores to carry out both destructive (core diameter of 64 mm, 79 mm, and 103 mm) and non-destructive tests. The non-destructive test deals with the propagation of elastic and compressive waves by deriving the ultrasound pulse velocities. The results show that the assessment of the compressive strength of concrete depends strongly on the diameter of cores and the extraction zones. Furthermore, the derivation of the actual compressive strength by referring to the compressive strengths of the cores with a diameter of 64 mm shows a stringent appearance of a size effect. More interestingly, valuable details about the correlation between the concrete compressive strength assessment based on destructive and non-destructive tests are also presented.