4.1.4 Ultrasonic characterisation of steel fibre orientation in ultra-high performance concrete

20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019
2019-06-25 - 2019-06-26
Nürnberg, Germany
4.1 Werkstoffprüfung und -charakterisierung 1
B. Ankay, K. Metje, T. Mönig, C. Zhang, T. Leutbecher - Universität Siegen (Deutschland)
310 - 317


Ultrasonic technology has proven to be a reliable non-destructive method for testing engineering applications. Especially for complex composites, like fibre-reinforced plastics or fibre-reinforced concrete, the pulse velocity method can be used to analyse the fibre-induced anisotropy. In the present study, ultrasonic testing was applied to investigate the fibre orientation in ultra-high performance fibre-reinforced concentrate (UHPFRC). UHPFRC is a composite consisting of concrete and steel fibres, which distinguishes itself from conventional concrete by higher compressive and tensile strength as well as a particularly high durability. Steel fibres influence the tensile behaviour after the formation of micro-cracks decisively and increase the ductility of UHPFRC members. The orientation and distribution of fibres significantly influence the bearing behaviour and are thus important parameters when designing UHPFRC members. In ultrasound experiments, the main orientation of the fibres in UHPFRC specimens was determined by a method based on analysing the wave velocities of polarised shear waves. Subsequently, the specimnes were cut perpendicular and parallel to the predominant fibre alignment predicted by ultrasonic testing and the actual orientation of the fibres in the cross-sections was evaluated by an optoanalytical method. Comparison of test data suggests that the proposed ultrasonic testing method is a suitable tool for predicting the predominant fibre alignment in UHPFRC members.