Assessment of Compressive Strength of OPC and PPC-Based Concretes Combined by Ultrasonic Pulse Velocity and Rebound Hammer

Abstract

In this study, non-destructive tests were performed on ordinary Portland cement (OPC) and Portland pozzolana cement (PPC) based concrete specimens, namely the ultrasonic pulse velocity (UPV) and rebound hammer (RN). A relationship is thus established between the NDT values and the compressive strength. A statistical regression analysis was performed between the compressive strength with UPV and RN values to obtain a best-fit relationship and correlation coefficients. To take into account the possibility that the relationship thus obtained may result in a lesser fitted curve, adjusted correlation coefficients were taken into account. It was found that UPV results in more efficient prediction of compressive strength of concrete when the type of concrete is considered, while RN results in much better results when the type of concrete is ignored. However, combined UPV and RN values provided an improvement in the prediction of concrete strength and proved to be efficient and reliable closer to the actual measured strength. Further, the relationships obtained for PPC had higher correlation coefficients compared to OPC-based concrete specimens. The relationships established were also compared with other relationships from previous researchers and were found to be more consistent.

Keywords: NDT, concrete, strength, correlations