Condition assessment of concrete by hybrid non-destructive tests

This paper presents interim findings of a research project that was aimed to develop reliable methods to assess the condition of bridges and port-structures. The use of different types of non-destructive testing (NDT) equipment in assessing in situ concrete such as that for concrete cover measurement and locating the arrangement of the reinforcements, air permeability, electrical resistivity and the half-cell potential is reported in this paper. Six electrically inter-connected reinforced concrete (RC) specimens were made under laboratory conditions to validate NDT equipment output and to correlate them. Field testing was then conducted on the exterior of an RC wall of Doug McDonell Building at the University of Melbourne, Parkville campus. The results show that the use of multiple NDT equipment can enhance the understanding of the in situ condition by minimising the limitation inherent in each of the equipment. Combination of output from different testing methods allows a more precise condition assessment of the RC structure. In addition, measurements can be used to estimate the service life of the RC element.