CORDIS provides links to public deliverables and publications of HORIZON projects.
Links to deliverables and publications from FP7 projects, as well as links to some specific result types such as dataset and software, are dynamically retrieved from OpenAIRE .
Deliverables
Overview & main innovative features/benefits:
For the first time ever, one research project has attempted to develop an integral design approach to steel fibre reinforced concrete. Based on the work done in the RILEM TC162-TDF commission, the present project has succeeded in the proposal of a unified design method, based on the one hand on the results of the beam test, and on the on other hand on the well-known sigma-epsilon method for ordinary concrete (which means that the design method is quite similar to the design of ordinary concrete and thus relatively easy to use).
Laboratory tests have been done to validate the formulas for sections subjected to shear, bending and normal force imposed and restrained deformation, and splitting. Furthermore, long-term tests have been executed to account for the important effects of creep, durability, and fatigue in the design approach. The first models for the structural level still need further development, but an important step has been taken towards the design and calculation of SFRC structures; they will be checked against the results of full-scale experiments.
Potential applications:
Since the sigma-epsilon method is based on the well-known, traditional concrete design approach, it can be anticipated that it will be integrated in the existing "community" of reference documents rapidly. The design method is expected to be adopted by the following code-drafting groups/organisations:
- As a RILEM Recommendation (1 to 2 years).
- As a fib document (3 to 5 years).
- As a part of the Eurocode 2 "concrete" system (CEN) (3 to 5 years).
- National normative or regulatory bodies such as CUR, Dafst.
End users:
- Designers of steel fibre reinforced concrete.
- Industrial manufacturers of steel fibre reinforced concrete (pre-cast plants, tunnelling and pavement contractors,) for determining their SFRC alternative solutions.
- Steel fibre manufacturers.
Overview & main innovative features/benefits:
An extensive round robin test programme together with the connected analysis has clearly indicated the ability of the 3-point bending test proposed by RILEM TC162-TDF to determine the toughness characteristics of steel fibre reinforced concrete. Thanks to the notch in the centre of the beam, and the fact that the test is piloted by a CMOD gage, the test has been shown to be very robust (low variability due to the test set-up in different testing labs) and run in a very stable manner, even with very brittle, high strength concrete matrices.
Further characteristics are:
- One CMOD measurement on the bottom of the beam is sufficient to run the test.
- A correlation has been established between displacement and CMOD measurements.
- A correlation has been established between CMOD measurements at different positions on the beam specimen.
- A method has been proposed to determine design parameters (for the s-e design approach, see result titled: "Design of SFRC based on the sigma-epsilon approach".
Potential applications:
Given the relatively simple configuration, and the excellent behaviour, the beam test has all the potential to rapidly become a RILEM recommendation, and in a later stage a CEN standard, connected to the CEN product standard on steel fibre reinforced concrete that is at this moment being elaborated.
End users:
- Laboratories involved in research into steel fibre reinforced concrete.
- Industrial manufacturers of steel fibre reinforced concrete (pre-cast plants, tunnelling and pavement contractors, ready-mix concrete plants) for determining concrete mix proportions and internal quality control.
- Organisations responsible for external quality control.
- Steel fibre manufacturers.
Overview & main innovative features/benefits:
An extensive round robin test programme together with the connected analysis has clearly indicated the scientific potential of a new direct tensile test, largely based on the test proposed by RILEM TC162-TDF to determine the toughness characteristics of steel fibre reinforced concrete. The test specimens are cast or cored CEB-cylinders, cut to approx. 150mm length, and with a 15mm deep circumferential notch. Further characteristics of the tensile test are:
- The specimens are glued onto steel loading platens of the testing machine (that itself has high rotational stiffness).
- The test specimen is instrumented with three extensometer readings, mounted across the notch at 120° from each other, the average of which is used to control the test.
- The variability in the SFRC specimen results is large but corresponds very well with the number of fibres effectively crossing the ligament.
- Criteria have been forwarded for the limitation of the difference between individual extensometer readings and the average, in order to accept or reject the test.
Potential applications:
The cylinder configuration is far more difficult, and consequently more expensive than the beam configuration. The test has several advantages over the bending test, especially for development work (new fibre types) and scientific work (the test is more directly linked to the s-w design approach). Therefore, the tensile test has all the potential to rapidly become a RILEM recommendation, and in a later stage a CEN standard, connected to the CEN product standard on steel fibre reinforced concrete that is at this moment being elaborated.
End users:
- Laboratories involved in research into steel fibre reinforced concrete.
- Steel fibre manufacturers.
Overview & main innovative features/benefits:
Starting from a fracture mechanical background, the sigma-w design method is undoubtedly the more refined, the more fundamental method of the two design approaches. Also for this method, for the first time ever, this research project has developed an integral set of design models for steel fibre reinforced concrete. Design tools have been developed for:
- Analysis of SFRC sections subjected to bending combined with normal forces.
- Evaluation of the load-deflection behaviour of the bending test specimen.
- Design of slabs on grade for temperature and shrinkage induced cracks.
- Design of pipes under crushing load configuration.
Further work includes shear design as well as SFRC combined with conventional reinforcement. With the introduction of the so-called "verification curves" it seems possible to determine design sigma-w curves from the bending test (so that the more expensive tensile test would not be a prerequisite to use the sigma-w design method).
Potential applications:
Compared to the sigma-epsilon method, the sigma-w design method presents to most designers a radically new approach that may be quite difficult to get acquainted with. It is believed that the potential of the latter method is larger for some applications, and therefore all means (e.g. computer programs) will be used to integrate also this design method in the existing "community" of reference documents.
The design method will be adopted by the same code-drafting groups/organisations as for the sigma-epsilon method, but probably with a delay of 3 years or so.
- As a RILEM Recommendation.
- As a fib document.
- As a part of the Eurocode 2 "concrete" system (CEN).
- National normative or regulatory bodies such as CUR, Dafst.
End users:
- Designers of steel fibre reinforced concrete.
- Industrial manufacturers of steel fibre reinforced concrete (pre-cast plants, tunnelling and pavement contractors,) for determining their SFRC alternative solutions.
- Steel fibre manufacturers.
- Finite element code producers (i.e. DIANA, ATENA, etc).
- Researchers.
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