Robotergestützte, magnetische Ausrichtung von Mikro‐Stahldrahtfasern in dünnwandigen UHPFRC‐Bauteilen

Ledderose, Lukas; Lehmberg, Sven; Budelmann, Harald; Kloft, Harald

doi:10.1002/best.201800083

Cited by 6 publications

(7 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, in this case, at least 1% by volume, or a fiber content of 40%, could be saved by the MFA process. This level of savings potential is also basically in agreement with the results of previous bending tensile tests [3].…”

Section: Table 4 Measured Values From the Tensile Tests And Comparati...supporting

confidence: 91%

“…The angular range could even be limited to 0°-15° by adjusting the parameters, and the strands could be compacted down to a fiber content of 10% by volume (Figure 6 (left)). A numerical approach to include this fiber distribution, which is not nonhomogeneous across the cross section, in the calculation of the flexural strength is explained in [3,31]. For component thicknesses of or below 30 mm, such as the dog-bones investigated, an alignment uniformly distributed over the cross-section was achieved with fiber angles deviating only moderately from the tensile direction (Fig.…”

Section: Process Parametersmentioning

confidence: 99%

“…The effect of near-surface fiber concentration can be used for components that are exposed to a one-sided bending load. For this, detailed experimental and numerical investigations have already been carried out at ITE [3]. However, in order to perform measurements cleaned from this effect regarding the actual tensile load capacities, an experimental setup for centric tensile tests was developed for UHPFRC components of small thickness.…”

Section: Centric Tensile Testsmentioning

confidence: 99%

“…Extensive research on the magnetic alignment of MSF has been conducted at ITE over the past decade. For example, UHPFRC components have already been developed in projects of the DFG Priority Program 1542 "Concrete Light" [2], which were treated with the MFA process in first probing tests [3]. In addition, studies and experiments on the topic of magnetic fiber alignment in UHPFRC have been continuously conducted at ITE since 2014.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Magnetic Alignment of Microsteel Fibers as Strategy for Reinforcing UHPFRC

2022

Self Cite

View full text Add to dashboard Cite

The objective of this paper is to provide an insight into current basic research at ITE on the manufacturing process of resource-efficient components through the controlled, automated magnetic distribution and alignment of steel fibers in UHPFRC (Ultra-High Performance Fibre-Reinforced Concrete). The method for distributing and aligning steel fibers in UHPFRC is based on the physical phenomenon of magnetism. Since steel fibers are ferromagnetic, magnetic fields can selectively change their position in the fresh concrete and align them according to the force flow and the maxim "form follows force". The magnetic fiber alignment (MFA) process developed on this principle combines the capabilities of digital and automized component manufacturing with the potential of targeted fiber alignment to increase the material efficiency of UHPFRC. It is highlighted at four levels: UHPFRC At the material level, studies were conducted on the composite properties of different brand-new and recycled microsteel fibers (MSF), formwork designs suitable for the MFA process were developed, flux densities of different magnets were simulated with special software solutions and measured in practice, and an end effector was fabricated that was implemented on 3- and 6-axis kinematics. At the process level, the interaction of the main parameters of the MFA process was evaluated by visual analysis on transparent glucose syrup-based solutions, and series of specimens were analyzed by micro-CT scans. At the component level, centric tensile tests were performed on a wide variation of dog-bones to provide an assessment of the potential increase in tensile performance of UHPFRC by the MFA process. At an economic and environmental evaluation level, the results from the tensile tests were used to assess and quantify the potential savings from reducing the fiber content and using recycled steel fibers.

show abstract

Section: Table 4 Measured Values From the Tensile Tests And Comparati...supporting

confidence: 91%

Section: Process Parametersmentioning

confidence: 99%

Section: Centric Tensile Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic Alignment of Microsteel Fibers as Strategy for Reinforcing UHPFRC

2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…The fiber distribution and orientation strongly depends on the casting conditions of the fresh mix as well as geometric constraints, and the effect of casting-induced variations in fiber orientations on SFRC structural performance has been shown in previous research [8][9][10][11]. Some methods to control the fiber alignment in fresh concrete have also been proposed, e.g., by [12,13]. The effect of the fiber orientations on the load-bearing performance of concrete is accounted for in current design guidelines [2,14] by introducing a so-called fiber orientation factor, which reduces the nominal tensile strength value of fiber reinforced concrete, accounting for favorable and unfavorable fiber alignment effects as well as isotropy.…”

Section: Introductionmentioning

confidence: 99%

Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete

et al. 2022

View full text Add to dashboard Cite

Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability. Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits. Fiber reinforcement can, however, have critical disadvantages and even hinder the performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study, ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development.

show abstract

Hybrid assessment of fiber orientation influence on the load resistance of anchors in SFRC

Mellios,

Losse,

Spyridis

2023

Civil Engineering Design

View full text Add to dashboard Cite

The consistent evolution of concrete has led to a variety of concrete types that enhance the material's versatility, cost‐efficiency and sustainability. Despite the rapid development and extensive research regarding steel fibre reinforced concrete (SFRC) in the last decades, there are still knowledge gaps on the material's resistance against locally applied tension loads on anchor bolts, as well as the interaction of possible non‐homogenous fibre orientations on the anchorage axisymmetric stress field. This aspect becomes particularly relevant since anchors are placed at the component boundaries, where fibres tend to align parallel to the external surface. Through an innovative experimental investigation on 64 single bonded anchors using layer‐casting concrete and a supporting set of non‐linear finite element simulations, this work aspires to exhibit the influence of controlled unidimensional fibre orientation on the load‐bearing capacity and behaviour of anchorages in SFRC.This article is protected by copyright. All rights reserved.

show abstract

Robotergestützte, magnetische Ausrichtung von Mikro‐Stahldrahtfasern in dünnwandigen UHPFRC‐Bauteilen

Abstract: Tab. 2 Materialkennwerte des UHPFRC ND-2,5 [6] Material properties of UHPFRC ND-2,5 [6] Kennwert Mittelwert Zylinderdruckfestigkeit (d/h = 80/160 mm) 138 MPa Einachsige Zugfestigkeit (d/h = 80/160 mm) 9 MPa Prismenbiegezugfestigkeit (b/h/l = 40/40/160 mm) 17 MPa Elastizitätsmodul 49,2 GPa

Cited by 6 publications

References 8 publications

Magnetic Alignment of Microsteel Fibers as Strategy for Reinforcing UHPFRC

Magnetic Alignment of Microsteel Fibers as Strategy for Reinforcing UHPFRC

Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete

Hybrid assessment of fiber orientation influence on the load resistance of anchors in SFRC

Contact Info

Product

Resources

About