Influence of steel reinforcement on ultrasonic pulse velocity as a non-destructive evaluation of high-performance concrete strength

Abstract

The objective of the present study is to highlight steel reinforcement influence on ultrasonic pulse velocity (UPV) measurements as a mean of a non-destructive strength assessment of high-performance concrete (HPC) used in real structures. In the first part, a mathematical model UPV-compressive strength for HPC is developed in the aim of assessing on site concrete strength as it evolves with loading history under an ever aggressing environment. At a second stage, cylindrical moulds made of HPC were reinforced with different longitudinal steel ratios (low, moderate and high) to simulate real practical cases. These moulds were then subjected to UPV tests in order to study the reinforcement influence on UPV and develop a correction factor for this UPV used in the UPV-strength correlation model elaborated to take account of the reinforcing steel in HPC. The modified UPV-strength correlation model was then used to evaluate the strength in real HPC structures of similar strength range, in order to assess its applicability and hence determine the in situ compressive strength of these structures. Within the HPC targeted in this work, with a strength varying from 55 to 85 MPa, the developed model has proved to be sufficiently accurate with very limited variability.