Auszugverhalten von Mikrostahlfasern aus UHPC unter monoton steigender und zyklischer Belastung/Pullout behaviour of micro steel fibres of UHPC under monotonic and cyclic loading

Oettel, Vincent; Lanwer, Jan-Paul; Empelmann, Martin

doi:10.37544/0005-6650-2021-01-02-27

Cited by 8 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In [ 23 , 24 ], the manufacturing process of the specimen is described in detail. The test program includes monotonic and cyclic loaded tests with a different length of embedment and angles of orientation.…”

Section: Experimental Investigationsmentioning

confidence: 99%

Fundamental Investigations of Bond Behaviour of High-Strength Micro Steel Fibres in Ultra-High Performance Concrete under Cyclic Tensile Loading

et al. 2021

View full text Add to dashboard Cite

The objective of the contribution is to understand the fatigue bond behaviour of brass-coated high-strength micro steel fibres embedded in ultra-high performance concrete (UHPC). The study contains experimental pullout tests with variating parameters like load amplitude, fibre orientation, and fibre-embedded length. The test results show that fibres are generally pulled out of the concrete under monotonic loading and rupture partly under cyclic tensile loading. The maximum tensile stress per fibre is approximately 1176 N/mm2, which is approximately one third of the fibre tensile strength (3576 N/mm2). The load-displacement curves under monotonic loading were transformed into a bond stress-slip relationship, which includes the effect of fibre orientation. The highest bond stress occurs for an orientation of 30° by approximately 10 N/mm2. Under cyclic loading, no rupture occurs for fibres with an orientation of 90° within 100,000 load changes. Established S/N-curves of 30°- and 45°-inclined fibres do not show fatigue resistance of more than 1,000,000 load cycles for each tested load amplitude. For the simulation of fibre pullout tests with three-dimensional FEM, a model was developed that describes the local debonding between micro steel fibre and the UHPC-matrix and captures the elastic and inelastic stress-deformation behaviour of the interface using plasticity theory and a damage formulation. The model for the bond zone includes transverse pressure-independent composite mechanisms, such as adhesion and micro-interlocking and transverse pressure-induced static and sliding friction. This allows one to represent the interaction of the coupled structures with the bond zone. The progressive cracking in the contact zone and associated effects on the fibre load-bearing capacity are the decisive factors concerning the failure of the bond zone. With the developed model, it is possible to make detailed statements regarding the stress-deformation state along the fibre length. The fatigue process of the fibre-matrix bond with respect to cyclic loading is presented and analysed in the paper.

show abstract

Section: Experimental Investigationsmentioning

confidence: 99%

Fundamental Investigations of Bond Behaviour of High-Strength Micro Steel Fibres in Ultra-High Performance Concrete under Cyclic Tensile Loading

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Under short-term static loading, in most UHPFRC components under bending, shear, and torsion, the desired fibre pullout always occurs [6,15,16].…”

Section: Fibre Design Philosophymentioning

confidence: 99%

“…The only mechanical difference between the fibres is the diameter. The authors of [15] give further detailed information regarding the high-strength micro steel fibre.…”

Section: Test Specimen and Test Configurationmentioning

confidence: 99%

“…2) 3) 4) 5) The investigations aimed to extend the understanding of the monotonic and fatigue behaviour of UHPFRC by isolated observations of its components. The study of [15] contains the investigations of the plain UHPC (part 2) as well as the UHPC-fibre interaction of single fibres (part 3). The tensile tests on small UHPFRC samples (part 5) will be the topic of a later article.…”

Section: Test Specimen and Test Configurationmentioning

confidence: 99%

“…The test specimens VM (fibre-group-pullout-tests, Figure 7) consisted of two plain UHPC cubes with nine oriented fibres located in between [15][16][17]. The concrete age of all tests was at least 28 days and the cylinder compressive strength reached more than 150 N/mm 2 .…”

Section: Test Specimen and Test Programmementioning

confidence: 99%

See 2 more Smart Citations

Fundamental Investigations on the Performance of Micro Steel Fibres in Ultra-High-Performance Concrete under Monotonic and Cyclic Tensile Loading

Lanwer

Empelmann

2021

Applied Sciences

View full text Add to dashboard Cite

: Ultra-high-performance fibre-reinforced concrete (UHPFRC) can preferably be used for lean and thin-walled structures due to its very high compressive strength. Based on the adverse relation between the increased load bearing capacities and the condensed dead weight of UHPFRC-structures, the impact of live loads in the design gets bigger and, in case of traffic loads, the effects of a cyclic loading have to be considered in more detail. In this context, this study investigated the material behaviour of UHPFRC, especially the tensile fatigue behaviour of high-strength micro steel fibres and the bond behaviour between those fibres and plain UHPC. The test programme included once tensile tests of high-strength micro steel fibres under monotonic and cyclic loading. Based on the test results, an S/N-curve was set up with the characteristic values. Furthermore, the test programme included pullout tests of fibre groups with different embedded lengths and orientations under monotonic and cyclic loading. It was observed that some fibres rupture under certain test configurations like the angle of orientation and the load amplitude.

show abstract

Verbundorientiertes Faserdesign in UHFB

Lanwer,

Empelmann

2024

Beton und Stahlbetonbau

View full text Add to dashboard Cite

Im Beitrag wird ein Ansatz für ein verbundorientiertes Faserdesign in ultrahochfestem Beton (UHFB) vorgestellt. Im Gegensatz zur bisherigen, weitgehend auf Erfahrungswerten und Eignungsprüfungen basierenden Methodik zur Wahl von Faserart, Fasergeometrie und Fasermenge werden in dem vorgestellten Ansatz das reale Faserauszugsverhalten in dem gewählten UHFB und mechanisch hinterlegte Effekte aus der Faserorientierung erfasst und berücksichtigt. Die Grundlage bilden Auszugversuche von hochfesten Mikrostahlfasern unter monoton steigender Belastung mit variierender Einbindetiefe und Orientierung. Der hieraus mit Bezug auf die Zugfestigkeit der Faser bestimmte Ausnutzungsgrad bildet den Grundwert für das Faserdesign. Bei schief orientierten Fasern muss darüber hinaus eine zusätzliche Biegebeanspruchung infolge der Umlenkwirkung an der Faseraustrittstelle berücksichtigt werden, die zu einer Erhöhung des Ausnutzungsgrads führt. Die konsistente und mechanisch begründete Berücksichtigung dieser Effekte stellt einen neuartigen Ansatz im Rahmen eines verbundorientierten Faserdesigns unter ökonomischen und ökologischen Gesichtspunkten dar.

show abstract

Auszugverhalten von Mikrostahlfasern aus UHPC unter monoton steigender und zyklischer Belastung/Pullout behaviour of micro steel fibres of UHPC under monotonic and cyclic loading

Cited by 8 publications

References 0 publications

Fundamental Investigations of Bond Behaviour of High-Strength Micro Steel Fibres in Ultra-High Performance Concrete under Cyclic Tensile Loading

Fundamental Investigations of Bond Behaviour of High-Strength Micro Steel Fibres in Ultra-High Performance Concrete under Cyclic Tensile Loading

Fundamental Investigations on the Performance of Micro Steel Fibres in Ultra-High-Performance Concrete under Monotonic and Cyclic Tensile Loading

Verbundorientiertes Faserdesign in UHFB

Contact Info

Product

Resources

About