Presentation on 16th October 2018 by Isaak Tsalicoglou at the 3rd Japanese-Swiss workshop titled "Durability Testing of Concrete, on site and in the lab", at TFB in Wildegg, Switzerland.
The state of the art of non-destructive testing applied to civil engineering has in recent years achieved many significant milestones in the field of imaging technologies for the assessment of reinforced concrete structures. The constant improvement of the available electronic components and the increased computational power of consumer-grades mobile devices are among the key factors that drove mature technologies such as Ground Penetrating Radar (GPR) and Eddy Current Testing (ECT) into products delivering new levels of accuracy and usability. At the same time, recent developments of the pulse-echo-based Ultrasonic Tomography (UT) further broadened the range of applications potentially addressed. Still, there seems to be a general lack of awareness in the user community about the real potentials and main limitations of each of the three technologies. The current work focuses on the typical scenarios and the common challenges presented by tasks of embedded object detection (structural details, steel reinforcement, utility network) and flaw detection (voids, cracks, delaminations). The complementarity of the three technologies has been proven through measurements on test blocks and real-life cases. It is noted that the proper combination of technologies naturally results in more efficient workflows, increased positioning accuracy, and a less subjective, operator-dependent interpretation of the testing results.