On the Design of Permanent Rock Support Using Fibre-Reinforced Shotcrete

Sjölander, Andreas; Ansell, Anders; Nordström, Erik

doi:10.3390/fib11020020

Cited by 3 publications

(9 citation statements)

References 24 publications

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“…For an analytical design, the residual flexural strength is normally used. As shown by Sjölander et al [4], the volume fraction of fibres depends on the design philosophy and the material. Commonly, a volume fraction between 0.5 and 1.0% of fibres is sufficient, with respect to structural performance.…”

Section: Introductionmentioning

confidence: 95%

“…The material parameters for the damage model were determined based on simulations of test results for beams, tested according to EN-14488-3 [8], as presented by Sjölander et al [4,24]. Here, macro fibres, i.e., structural fibres, made of steel (Dramix 3D and 4D), synthetic (BarChip 54), and basalt (MiniBar), were used in various dosages to investigate the structural performance.…”

Section: Simulation Of Beamsmentioning

confidence: 99%

“…Here, macro fibres, i.e., structural fibres, made of steel (Dramix 3D and 4D), synthetic (BarChip 54), and basalt (MiniBar), were used in various dosages to investigate the structural performance. More details on the tests are given in [4,24]. The EN-14488-3 is a four-point bending test on a simply supported beam with dimensions 500 × 125 × 75 mm (Length × Width × Height).…”

Section: Simulation Of Beamsmentioning

confidence: 99%

“…Data Availability Statement: Data from experimental testing available in Sjölander, Andreas; Ansell, Anders; Nordström, Erik (2022); "Data from structural testing of sprayed and cast shotcrete reinforced with fibres of steel, basalt and synthetic material", Mendeley Data, V1, https://doi.org/10.17632/d7 n5mvb2sg.1 [24].…”

Section: Institutional Review Board Statement: Not Applicablementioning

confidence: 99%

“…Energy absorption at 40 mm deflection of round panels, from[4,24]. Results from experiments and calculated results from beam parameters.…”

mentioning

confidence: 99%

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Post-Cracking Behaviour of Fibre-Reinforced Shotcrete: A Numerical Comparison between Beams and Panels

Östlund,

Sjölander,

Brodd

2023

Fibers

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Fibre-reinforced shotcrete is an essential part of the support of hard rock tunnels. Due to the complexity of the design, a combination of empirical and numerical analysis is commonly used in the design. The required dosage of fibres for structural purposes is determined based on minimum energy absorption or residual flexural strength. The latter is derived from tests on beams, while energy absorption is tested on panels. It is widely known that tests on beams suffer from a large scatter in results due to the short fracture zone in combination with the natural variation in the number and orientation of fibres which bridge the crack. This impacts the characteristic strength derived from these tests negatively. This paper presents a numerical study to investigate how the test method affects the required dosage of fibres. First, a non-linear model for shotcrete based on continuum damage mechanics is presented. Thereafter, the model is tuned against test results for beams and panels. A model tuned on beams is then used to simulate the response of a panel and vice versa. The results indicate that the size of the fracture zone has a significant effect on the post-cracking behaviour and that the required dosage of fibres could be decreased if specimens with longer fracture zones, i.e., panels or slabs, are used.

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Section: Introductionmentioning

confidence: 95%

Section: Simulation Of Beamsmentioning

confidence: 99%

Section: Simulation Of Beamsmentioning

confidence: 99%

Section: Institutional Review Board Statement: Not Applicablementioning

confidence: 99%

“…Energy absorption at 40 mm deflection of round panels, from[4,24]. Results from experiments and calculated results from beam parameters.…”

mentioning

confidence: 99%

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Post-Cracking Behaviour of Fibre-Reinforced Shotcrete: A Numerical Comparison between Beams and Panels

Östlund,

Sjölander,

Brodd

2023

Fibers

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The Use of Slag in Accelerated Shotcrete for Rock Support: A Pilot Study on the Influence on the Early Compressive Strength

Brodd,

Sjölander,

Östlund

2023

Nordic Concrete Research

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Today, the world is facing an enormous challenge where the emissions of greenhouse gases must be reduced significantly to stop the increasing mean temperature. For the construction industry, this challenge means that structures must be designed more carefully, and materials must be used and produced more efficiently. Concrete is one of the most widely used materials, and cement production alone contributes to around 8 % of the world’s total CO2 emissions. This paper presents a pilot study in which part of the cement clinker content in accelerated shotcrete is replaced with ground granulated blast furnace slag (GGBS). Shotcrete is widely used as part of the rock support for tunnels in hard rock and has a large cement content. Thus, the environmental impact must be reduced significantly to meet future demands. However, introducing GGBS will slow down strength development, which is a crucial part of shotcrete. Thus, this paper aims to investigate the early strength development, i.e., after one and seven days. The results show that an average compressive strength of 18 MPa can be reached after 24 hours when 35 % of the cement clinker content is replaced with GGBS. Finally, some important topics for further studies are pointed out.

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Influence of Polymer Fibre Reinforcement on Concrete Anchor Breakout Failure Capacity

Spyra,

Mellios,

Borttscheller

et al. 2024

Polymers

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With the increasing use of fibre-reinforced concrete, e.g., in industrial floor and tunnel construction, the associated fastening technology in this material has increasingly become the focus of scientific attention in recent years. Over 25 years ago, design and assessment guidelines for anchoring systems in reinforced concrete were established, which have since evolved into comprehensive regulatory standards. However, these standards only address plain and rebar-reinforced concrete as anchoring bases, neglecting fibre-reinforced concrete. The design of anchorage systems in fibre-reinforced concrete has not yet been standardised. Recent studies and product certifications accounting for steel fibre reinforcement are now seeing their way to publication, supported by a fair amount of scientific research studies. This paper aims to elucidate the effects of polymer fibre reinforcement in this application through a systematic investigation. Experimental studies were conducted to evaluate the system’s load-bearing behaviour failing with concrete breakouts under tensile loading. By incorporating the determined material properties of polymer fibre-reinforced concrete and their mathematical interpretation, alternative model proposals are presented to assess concrete breakout resistance. The addition of polymer fibres significantly improves the load-bearing capacity and ductility of concrete under tensile loads, transforming its quasi-brittle response into a more ductile behaviour. Although the fibres had a minor impact on overall material strength, their influence on the tensile capacity of the anchors reveal a 15–20% increase in load resistance and up to a doubling of the failure displacements.

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On the Design of Permanent Rock Support Using Fibre-Reinforced Shotcrete

Cited by 3 publications

References 24 publications

Post-Cracking Behaviour of Fibre-Reinforced Shotcrete: A Numerical Comparison between Beams and Panels

Post-Cracking Behaviour of Fibre-Reinforced Shotcrete: A Numerical Comparison between Beams and Panels

The Use of Slag in Accelerated Shotcrete for Rock Support: A Pilot Study on the Influence on the Early Compressive Strength

Influence of Polymer Fibre Reinforcement on Concrete Anchor Breakout Failure Capacity

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