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Grouting Defects Localized by Ultrasonic Testing Including Phase Evaluation

Grouting defects, e.g. in post-tensioned structures or piped anchors may be identified by ultrasonic imaging. Since several years experiences are carried out with false color displayed phase values, which enable distinct localization of ungrouted regions. In this contribution we report on progress in localizing grouting defects in tendon ducts, when they are only partly grouted and the unfilled part is not orientated into the direction of the measuring surface. This is frequently the case e.g. for box girder structures. During the project specimens containing different types of grouting faults are investigated in order to optimize measuring and evaluation techniques. A handheld linear array system (commercially available) is applied for fast 2D-measurement and subsequent phase sensitive 3D-imaging (new software development). In a large concrete wall specimen tendon ducts and real prestressing systems containing grouting defects were built in. The ducts are partly covered by non prestressed reinforcement bars in order to investigate its disturbing influence. These included objects were investigated afterwards with the described methods. We report on large area measuring results, which were partly verified by -radiography. In the frame of practical application results of measuring the position and extend of a blockade within a posttensioned structure are presented.

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