Spannbetonuntersuchung mit bildgebenden Ultraschallecho-Verfahren

Investigation of prestressed concrete using the imaging ultrasonic echo method - Application of phase evaluation for the distinction of reflectors:

The application of ultrasound methods for the non-destructive assessment of pre-stressed concrete members is one of the biggest challenges in the field of non-destructive testing in civil engineering. The inhomogeneous composition of concrete, reinforcement and tendons, which itself consist of ducts, steel wires and grouting material, requires an optimisation of measuring technique and analysis software to gain reliable information about the grouting condition of the ducts. This article describes the fundamentals of the visualisation of ultrasound echo data, the investigation and data analysis at specimen and a case study. Here especially the phase evaluation proves to be very useful for the distinction of reflectors. The basic principle is explained and parts of an interactive software module, which is based on the SAFT method, is presented. With this software it is possible to calculate, analyse and visualise 2D and 3D reconstructions of large ultrasound data sets with conventional PCs or mobile computers. Data has been analysed, which were recorded with automatic measurement systems at small scale laboratory specimens and a large scale testing wall. In the frame of the practical application it was possible to localise the position and extent of a blockade within a duct.