Experimental Characterization of the Flexural Behaviour of Steel Fibre Reinforced Concrete According to Rilem TC 162TDF Recommendations (original) (raw)
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Fracture Energy of Steel Fiber-Reinforced Concrete
Mechanics of Composite Materials and Structures, 2001
Steel fibre reinforced concrete (SFRC) is a cementitious material reinforced with a given content of discrete fibres. The use of SFRC in building construction has increased continuously due to its better mechanical properties, mainly, the energy absorption capacity.
FRACTURE ENERGY OF STEEL FIBRE REINFORCED CONCRETE
Steel fibre reinforced concrete (SFRC) is a cementitious material reinforced with a given content of discrete fibres. The use of SFRC in building construction has increased continuously due to its better mechanical properties, mainly, the energy absorption capacity.
2020
Steel fibre-reinforced concrete (SFRC) is widely applied in the construction of civil infrastructure projects, including the following: industrial floors, slabs, walls, and foundations. The application of steel fibres in the reinforcement of concrete remarkably improves the postcracking behaviour of such concrete. In order to estimate this property, the energy involved in absorption is measured by using several valid testing standards: EVS-EN 14651:2005, EVS-EN 14488-5:2006, and ASTM C1550-12a. The objective of this study was to carry out a comparable analysis of the results that have been obtained using previously-mentioned standards and to be able to find a more reliable method for the determination of the fracture toughness of SFRC specimens. Experiments were carried out in accordance with the chosen standards. It was concluded that procedure involved in the ASTM standard provides a smaller variability of results with better levels of repeatability, therefore a smaller volume of ...
Modified Fracture Energy Method for Fibre Reinforced Concrete
2013
Fibre manufacturers specify different parameters for measuring the performance of their fibres, e.g. Re3 number or σ-ε diagram. However, these parameters depend largely on the strength class of the concrete; most specifically on the fracture energy, which is in itself a variable from cement manufacturer to manufacturer, even within the same class. It follows therefore that any fibre performance parameters as specified by the manufacturer's laboratory may vary significantly for the same concrete class in the user's laboratory. The ideal would be to find a performance parameter that is fibre specific and at least partially independent of the concrete, which could then be used for characterizing and comparing the various fibre types. In this paper I present a fibre added energy that could be used to characterize the fibres in this way.
IJRASET, 2021
This The influence of fibre reinforcement on crack propagation in concrete was studied. Thirty-five double torsion specimens, made with three types of fibres (fibre glass , straight steel fibres and deformed steel fibres) were tested. The variables were the fibre volume and size of the fibres. The test results indicated that the resistance to rapid crack growth increased somewhat with increasing fibre content up to about 1.25%-1.5% by volume. The degree of compaction had an enormous effect on the fracture properties .The fracture toughness increased with fibre content up to about 1.25% by volume, and then decreased , due to incomplete compaction. It was found that in this test geometry, fibres did not significantly restrain crack growth. It was also observed that once the crack had propagated down the full length of the specimen, the system changed from a continuous system to a discontinuous system, consisting of two separate plates held together by the fibre reinforcement. Different types of fibres did not significantly affect the fracture toughness.
EXPERIMENTAL INVESTIGATION ON THE FRACTURE BEHAVIOUR OF STEEL FIBER REINFORCED CONCRETE
Concrete is a composite material used for construction worldwide. The presence of cracks and pores inside concrete material is inevitable and it is necessary to investigate if they are stable or not. Hence problems related to fracture are vital in concrete. Fracture study assesses the ductile behavior of concrete structures under loading using various fracture parameters. Plain concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Addition of closely spaced and uniformly dispersed fibers to concrete acts as crack arrestor and substantially improves its static and dynamic properties. As a result of this ability to arrest cracks, fiber composites possess increased extensibility and tensile strength, both at first crack and at ultimate, particular under flexural loading; and the fibers are able to hold the matrix together even after extensive cracking. The present study aims at finding out how far the ductility of concrete can be improved by the addition of steel fibers in terms of fracture parameters by varying the fiber content. The fiber content was varied from 0% to 1.2% with an increment of 0.2%. The mechanical properties such as cube compressive strength, flexural strength, split tensile strength and modulus of elasticity were studied. From that results the optimum percentage of fiber was decided. Three-point bending test on notched beams (fracture tests) were conducted for determination of fracture parameters. The tests were done as per the guidelines of International Union of Laboratories and Experts in Construction Materials, Systems and Structures(RILEM)
Behaviour of Fibre-Reinforced Concretes with Reference to Fracture Resistance
Fatigue & Fracture of Engineering Materials & Structures - FATIGUE FRACT ENG MATER STRUC, 1992
This paper examines the effect of beam size, fibre volume fraction and various fibres on the flexural behaviour of concretes, and their fracture resistance. The ratio of flexural strength to tensile strength is used as a measure of brittleness; a low value indicating a more brittle material. Two flexural toughness indices are used which provide a basis for analysing loadcleflection curves. The relation between these structural indices and the material fracture resistance is assessed by adopting parameters which involve flexural and tensile strengths alone and fibre length to reflect fracture resistance.
Fracture Energy of Hybrid Fiber Reinforced Concrete
2007
In this paper, high strength concrete (HSC) of 53 MPa compressive strength was investigated. The constituents of the mix are dolomite as a coarse aggregate with 14 mm maximum aggregate size, siliceous sand as fine aggregate mixed together with a ratio of 1: 1.675, 443 Kg/m 3 ordinary Portland cement and 49 kg/m 3 silica fume as a cementitious material, and w/c was 0.29. The experimental program was designed to investigate the mechanical properties and fracture behavior of that HSC but having 0.8% fiber volume fraction of different types of short fiber, FRCs, (steel, glass, PP, steel+glass, steel+PP, glass+PP, and steel+glass+pp). The fracture behavior of edge-notched beam was determined in three-point bending condition. The beam length to depth ratio L/d was constant and equals to 4. The crack length to depth ratio, a/d, was equal to 0.2, 0.3, 0.4 and 0.5. The fracture parameters were determined using linear elastic fracture machine and Hillerborg model. The results in the present paper indicated that, adding short fibers to HSC improved its compressive strength in addition to the obvious enhancement in ductility except in the case of glass fiber, where, the compressive strength of GFRC is lower than that of HSC. The mode of failure for various FRC types under compression was varied compared to that of plain concrete. All these cubes failed due to multiple tensile vertical cracks with sudden explosive failure in the case of GFRC. In general, a small effect of short fibers in improving the indirect tensile strength and flexural strength of HSC. HSC with steel and PP hybrid fiber (SPPFRC) showed superior compressive, tensile, and flexural strengths and flexural toughness over the others FRCs.
European Journal of Environmental and Civil Engineering, 2018
In the present experimental work, 28 reinforced concrete beams were manufactured and tested in bending under 2 concentrated loads. The beams, which were made in high strength concrete and in ordinary concrete for comparison purposes, had different quantities of fibres, with two aspect ratios. During the testing, a special attention was given to the monitoring of flexural cracking in terms of width, spacing and length, using a digital camera and Gom-Aramis software for the analysis of the recorded images. The measured crack widths were compared with theoretical values predicted by three major universal design codes for reinforced concrete, namely the American ACI 318, the British Standard 8110, the Eurocode 2, and by the technical document of Rilem TC 162-TDF. In the present experimental work, an amendment of the Rilem model, taking into consideration the three important parameters, namely the quantity of fibres, their orientation factor and their aspect ratio, is proposed. The predicted values of the crack width obtained by the modified Rilem model were compared with the test values and assessed against other experimental data on fibre-reinforced concrete beams taken from the literature. The results show that the modified Rilem model is fairly reliable in predicting the crack width of fibre-reinforced concrete.
More efficient and industrialised construction methods are both necessary for the competitiveness of in-situ concrete and essential if the construction industry is to move forward. At present, the expenditure on labour (preparation and dismantling of formwork, reinforcing, and casting and finishing of concrete) almost equals the cost of material. Fibre-reinforced concrete (FRC) extends the versatility of concrete as a construction material, offers a potential to simplify the construction process and, when combined with self-compacting concrete, signifies an important step towards industrial construction. However, a barrier to more widespread use of FRC has been the lack of general design guidelines which take into account the material properties characteristic of FRC, i.e. the stress-crack opening (sigma-w) relationship. The presented work has been focused on FRC, showing a strain-softening response, and the interrelationship between material properties and structural behaviour. Thi...