Concrete Strength Evaluation through indirect UPV

The assessment of concrete properties in existing r/c buildings is a topic of fundamental importance to get reliable safety checks in structural retrofitting or seismic rehabilitation. Among other techniques, the ultrasonic pulse velocity test (UPV) is largely employed to estimate the concrete strength. This is because UPV is a non destructive method, easy to perform and provides reliable results. Several formulas are available in technical literature to relate the UPV measurements to concrete strength. These formulas are robust and reliable above all for direct measurements. Unfortunately these direct measures are a problem for existing buildings where, for a number of reasons, it is often necessary to perform indirect or, at most, semi-direct tests. In these cases relations available in the literature are not definitive. The present paper aims to contribute to develop a correlation between direct and indirect (or semi-direct) measures in order to use this latter kind of measure for reliable concrete strength estimations.