Further Investigations Regarding a New Approach on Estimating Concrete Compressive Strength via Ultrasonic Pulse Velocity

One main focus pursued by many researchers is developing faster and cheaper non-destructive methods (NDT), whilst increasing the accuracy in estimating the concrete mechanical properties, mainly the compressive strength. In many cases, the NDT approach is preferred because of its non-destructive nature. Despite the fact that the destructive testing (DT) delivers more accurate results, the number of concrete cores is, in general, limited because of invasive nature upon evaluated elements and thus can lack sufficient data for the analyze and further on, for drawing appropriate conclusions. Furthermore, it is a known fact that concrete strength may vary between the same elements. With the DT it is difficult to quantify the internal flaws of the concrete, such as internal cracks, delamination, or voids, because it is recommended to avoid those areas when coring. The purpose of this paper is to further investigate a proposed method on a new set of concrete cores extracted from a multistorey building, in order verify its validity and accuracy. The new approach is solely based on ultrasonic pulse velocity (UPV) testing which delivers data concerning relevant parameters (air-dry density, dynamic modulus of elasticity, static modulus of elasticity) leading to concrete compressive strength evaluation. In the process of determining the dynamic modulus of elasticity, the dynamic Poisson’s coefficient was considered in accordance with values provided by the technical literature, and it is not experimentally determined for this step of the investigation.