Correlation curves to characterize concrete strength by means of UPV tests

In the design of interventions and/or in the evaluation of vulnerability of an existing reinforced concrete structure, a crucial role is played by the assessment of the concrete compressive strength. The estimation of such parameter may be obtained by destructive tests, which, even if may give an accurate estimation, usually can be performed on a limited number of points. Otherwise, non-destructive tests have been proposed which proceed by acquiring physical measurements which can be reported to the concrete compressive strength. In the present study, the results of an experimental campaign performed on an existing building in the area of Bari (Italy) are presented. The tests involved both destructive tests and Ultrasonic Pulse Velocity tests. Several possible test conditions are defined by combining the available data and varying the number of considered cores. The correlation curves have been evaluated for each one of the possible test conditions, and some considerations are discussed on the relationship between the parameters of such correlation models by varying the number of considered cores.