Experimental investigations of UHPC, steel fibres and embedded steel fibres under cyclic tensile loading

Author(s): Martin Empelmann, Vincent Oettel, Jan-Paul Lanwer
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 756-763
Total Pages: 848
Language: English

Abstract: Modern high performance concretes, like ultra-high performance fibre-reinforced concrete (UHPFRC), need for avoidance of brittle failure modes a relatively high fibre content, which leads to an overcritical tensile load-bearing behaviour and a high post-cracking tensile strength. Additionally, UHPFRC can preferably been used for lean and thin-walled structures due to its very high compressive strength. The combination of weight reduction and high slenderness make UHPFRC-structures susceptible to cyclic loading, e.g. in case of bridge girders or masts and towers.
Currently, the effect of cyclic loading on UHPFRC, in particular the tensile bearing behaviour and post cracking tensile strength is not quite clear. Therefore, the degradation processes of UHPFRC under cyclic tensile loading have to be investigated fundamentally. This is done in experimental investigations by iBMB, Division of Concrete Constructions of TU Braunschweig, on small-sized specimens, like fibre tests and tensile tests on plain ultra-high performance concrete and as well as fibre pull-out tests. Within this test program, the number of cycles and amplitudes are varied to examine the mechanical properties and to display the degradation processes. Imaging techniques like digital microscopy, x-ray scans (CT) and scanning electron microscopy (SEM) are used to obtain the degradation of the fibre, the UHPC and the interfacial transition zone (ITZ) between fibre and UHPC. The following paper contains a current state of the research project “Degradation Processes of UHPFRC under cyclic tensile Loading” as part of the priority program SPP 2020 “Cyclic deterioration of High-Performance Concrete in an experimental-virtual lab” founded by the German Research Foundation (Ger. DFG).

Online publication :2019
Publication type : full_text
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