Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

"Mechanical characterisation of braided BFRP rebars for internal concrete reinforcement” presented at IALCCE2018 by Sofia Antonopoulou

33 views

Published on

This study investigates the tensile behaviour of basalt fibre reinforced polymer (BFRP) composites that were developed using braiding as a manufacturing technique. Those materials will be introduced in concrete reinforcement applications. Three BFRP rebar sizes with a circular constant cross section and different braided configurations are developed and characterised with respect to their internal architecture. The braid angle on each layer of the rebar, varying from 10◦ to 45◦, is an important parameter that has a direct impact on its performance characteristics. The effective longitudinal in-plane modulus (ExFRP) of each braided sample is calculated numerically using the classical laminate theory (CLT) approach and then, tensile tests are performed according to the relevant standard. Comparisons between analytical and experimental data demonstrate a significant influence of braiding parameters, like braiding angle and number of braiding layers, on the mechanical properties of BFRP rebars. In addition, it is noteworthy that all predicted moduli determined with CLT numerical approach are found to be higher than the test results and overestimate rebar’s stiffness, most probably due to the degree of undulation from braiding process.

Published in: Engineering
  • Be the first to comment

  • Be the first to like this

"Mechanical characterisation of braided BFRP rebars for internal concrete reinforcement” presented at IALCCE2018 by Sofia Antonopoulou

  1. 1. Reducing Uncertainty in Structural Safety Special Session SS6 Ghent, Belgium 28-31 October 2018
  2. 2. Sofia Antonopoulou, Ciaran McNally and Greg Byrne Mechanical characterisation of braided BFRP rebars for internal concrete reinforcement
  3. 3. Research Idea Aim of the project: Main goal: Design, Development & Characterisation of Basalt Fibre Reinforced Polymer composites, for internal concrete reinforcement, using braiding as a manufacturing technique Explore the potential of braided BFRP reinforcement in infrastructure applications
  4. 4. Background and Motivation Degradation of reinforced concrete structures due to corrosion of steel affects long-term durability & structural safety of RC elements Deterioration of global infrastructure Estimated global cost of corrosion ~ $ 2.5 trillion
  5. 5. Background and Motivation Replacement of steel as internal concrete reinforcement by FRP composites Main disadvantage of FRP Brittle failure without warning Advantages of FRP Corrosion resistant & Lightweight FRP properties strongly dependent on ❖ Type of fibre & matrix ❖ Fibre & void content ❖ Fibre-matrix interface ❖ Orientation of fibres
  6. 6. Background and Motivation Manufacture methods of FRP: ◆ Pultrusion low cost & continuous process ◆ Braiding additional ductility & increased bond with concrete Design guidelines for the efficient use of FRPs in construction: ◆ ACI-440.1R ◆ CSA-S806-02
  7. 7. Background and Motivation Basic principle of braiding: Interlacing of yarns in a diagonal direction - Multiaxial Orientation Braiding Angle: Affects mechanical properties of braids
  8. 8. Experimental Part Product name Uses Tensile strength (MPa) Elastic modulus (GPa) BASALTEX® - Basalt assembled roving – 300, 600, 2400 tex 13, 17, 19 μm Fibre reinforcement 2800 – 4800 87 - 89 M183 semi-dull round - PET Monofilament Impregnation aid 57 – 60 10 Easy Composites - IN2 Epoxy infusion resin/ Slow cure Resin 65.5 – 73.5 2.95 Manufacturing design & process of BFRP preforms Materials ❖ Basalt fibres ❖ PET fibres ❖ Epoxy resin 3 different rebar designs: ❖ 5 mm OD ❖ 8 mm OD ❖ 10 mm OD
  9. 9. Experimental Part Manufacturing design & process of BFRP preforms
  10. 10. Experimental Part BFRP 2 - 8 mm Layer Material Yarns OD Angle 1 300 8 1.6 12 2 300 16 2.7 16 3 600 16 4.0 17 4 PET 32 4.9 12 5 PET 32 5.6 14 6 300 16 6.5 16 7 600 16 7.2 45 8 600 24 7.9 40 BFRP 1 - 5 mm Layer Material Yarns OD Angle 1 600 8 2.5 14 2 PET 24 3.8 15 3 PET 24 4.0 15 4 600 16 4.9 45 BFRP 3 - 10 mm Layer Material Yarns OD Angle 1 300 16 2.6 14 2 600 16 4.2 16 3 PET 32 5.0 13 4 PET 32 5.4 14 5 600 16 5.8 34 6 600 16 6.2 36 7 600 24 7.1 30 8 PET 24 8.0 35 9 600 24 8.8 34 10 600 24 9.8 38
  11. 11. Experimental Part Numerical analysis – Mechanical characterisation Classical Lamination Theory (CLT) numerical approach Evaluation of elastic properties of braided composites
  12. 12. Results Sample no BFRP 1 BFRP 2 BFRP 3 OD (mm) 5 8 10 Fibre Volume Fraction (%)* 57.76 51.63 54.59 Aver./ CoV Aver./ CoV Aver./ CoV Maximum Load (kN) 5.46/ 0.05 17.84/ 0.01 30.60/ 0.02 Ultimate Tensile Strength (MPa) 277.84/ 0.05 354.99/ 0.01 389.64/ 0.02 Maximum Displacement (mm) 7.49/ 0.03 10.09/ 0.05 21.58/ 0.07 Ultimate Strain (%) 2.98/ 0.03 2.59/ 0.06 3.73/ 0.09 Elastic Modulus (GPa) 10.65/ 0.03 14.76/ 0.02 12.39/ 0.04
  13. 13. Results
  14. 14. Results
  15. 15. Conclusions • Design, development and characterisation of braided BFRP composites for internal concrete reinforcement. • Direct relation between braiding parameters & rebar’s performance. • Maximum tensile strength comparable to the one of steel. • Mechanical response mainly dominated by the textile architecture, affecting localized properties, crack propagation and load redistribution in the material.
  16. 16. Conclusions • Significant discrepancies between theoretical and experimental values for tensile properties, mainly due to the anisotropic nature and out-of-plane properties of braided composites. • Focusing on the design flexibility, additional work towards an improved rebar design is needed. • In addition, tensile fatigue tests and microstructure analysis using CT-scanning technique is currently in progress, aiming to evaluate their long-term durability, assess quality and consistency of the manufacturing process and correlate that with their mechanical performance.
  17. 17. sofia.antonopoulou@ucdconnect.ie The TRUSS ITN project (http://trussitn.eu) has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 642453 Thanks for your attention

×