Measurement of Properties of Fiber Reinforced Concrete (original) (raw)
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This work proposes a novel methodology for the complete characterization of fiber reinforced concrete (FRC). The method includes bending tests of prismatic notched specimens, based on the Standards for FRC, tensile and pure shear tests. The values adopted by the standards for designing FRC are the obtained from bending tests, typically fR3, even for shear and pure tension loading. This paper shows that the remaining strength of FRC, supplied by the fibers, depends on the type of loading. In the case of shear and tensile loading the prescriptions of the standards may be unsafe. In this work, the remaining halves of specimens subjected to bending test are prepared and used for shear and tension tests. This means significant savings in specimen preparation and a greater amount of information for structural use of FRC. The results provide relevant information for the design of structural elements of FRC compared with the only use of data supplied by bending tests. In addition, a video-e...
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 ...
GRD Journals, 2019
Fibers used to enhance the brittleness property of steel reinforced concrete and plain concrete, and modify the tensile strength by increasing work of fracture. Thus, the toughness measurements are valuable for assessing the post crack performance of fiber reinforced concrete (FRC). There are many international standard around the world, but this paper are focuses on review the American standard specifications via exclusive ASTM. The review involve the flexural strength testing methods and toughness testing methods for FRC. For flexural strength test, the ASTM C 78 and ASTM C 293 reviewed and compared between both, while for toughness the ASTM C 1018, ASTM C 1609, ASTM C 1399 and ASTM C 1550 reviewed. This paper also describes concisely the method for each testing and considerable advantages of these methods. Beside, abridged some limitation of these methods. All figures have been redrawn with inserted more details to be most obvious and more rich.
Fiber reinforced concrete: from flexural tests to solid slabs
Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures, 2019
Tensile behavior of fibre reinforced concrete is assessed based on flexural tests where specifically the post cracking strength values are of interest. However, the residual tensile strength values obtained based on such characterization test exhibit a very high scatter which is mainly due to the variation of number and orientation of fibres at the fracture plane. This rather unrepeatable behavior may cast doubt on the overall performance of a structure reinforced only with fibres and may question the validity of estimated tensile strength parameters that are used in the design of such from one specimen to another structures. While there is evidence that fibre reinforced concrete structures show a behavior that can be predicted by the average material properties, no strong proof is yet available. If so, then the low characteristic value of residual strength values may be a very conservative starting point for design of such structures To validate the reliability of design approach proposed for fibre reinforced concrete structures, twelve nominally identical fibre reinforced concrete slabs sized 2000×2000×150 mm, and twelve notched specimens sized 150×150×600 mm are tested, and the results are compared. Further, a yield line method is employed to predict the ultimate load bearing capacity of the slabs based on the tensile parameters obtained from the characterization tests. The results show that the average material properties can satisfactorily predict the bearing capacity of the slabs. FraMCoS X Conference.
Experimental studies on fiber reinforced concrete
The concepts of using fibres in order to reinforce matrices weak in tension is more than 4500 years old.since Portland cement concrete started to be used widely as a construction material attempts were made to use fibres for arresting cracks enhance the strength etc. The development of fibre reinforcement for concrete was very slow before 1960's. Fibers are generally used as resistance of cracking and strengthening of concrete. In this project we are going to compare the compressive strength of 3, 7 and 28 days of aramid fibres to the ordinary concrete and fibre reinforced concrete i.e. glass fibres and steel fibres. The concrete is design for M20 grade of concrete. According to various research papers, it has been found that steel fibers give the maximum strength in comparison and glass fibre is used for crack resistance but aramid simultaneously gives strength and can be used for crack resistance. Now a days there exists many reinforcement techniques for improving the strength of those materials which lacks load carrying and less durable capacity. Fiber reinforced concrete has been successfully used in slabs on grade, shotcrete, architectural panels, precast products, offshore structures, structures in seismic regions, thin and thick repairs, crash barriers, footings, hydraulic structures and many other applications. This review study is a trial of giving some highlights for inclusion of aramid fibers especially in terms of using them with new types of concrete.
Toughness testing of ultra high performance fibre reinforced concrete
2009
In this paper an investigation is made of the applicability of the ASTM C 1609 procedure for testing toughness of ultra high performance fibre reinforced concretes containing a large amount of fibre (C2% by volume) and exhibiting deflection hardening behaviour. All mixtures exhibited deflection hardening behaviour, and the parameters varied included (1) the amount of steel fibres, (2) the type of steel fibres, (3) the size of the longest fibre, (4) the addition of polypropylene fibres, and (5) the size of the maximum aggregate grain in the concrete matrix. Based on comparison of the curves obtained from flexural toughness tests with the evaluation of the test results obtained according to ASTM C 1609 and with the statistical analysis, the authors recommended additional toughness parameters (P 100,3.00 , P 100,4.00 , P 100,6.00 , T 100,3.00 , T 100,4.00 , and T 100,6.00) for the evaluation of toughness results. Such additional toughness parameters are calculated using a similar procedure as that specified in ASTM C 1609.
Analytical Review on Flexural Toughness of Fiber Reinforced Concrete
2006
The development of fiber reinforced concrete, which improves some lacks of normal concrete performance, gives great contribution in the future of structural application. Compared to plain concrete, tiber reinforced concrete has some mechanical properties advantages such as: ductility that conespond to energy absorption, impact resistant, tensile and flexural strength, fatigue life, shrinkage, abrasion, fragmentation, and spalling. lt should be noticed that the fiber addition will improve the bending resistance and ductility of concrete. Some methods of testing and calculating of flexural toughness have been adopted by various users. There are some limitations in current techniques of toughness characterization. An important consideration should be attempted in analyzing and implementing the methods of testing and evaluating of the flexural toughness of steel fiber reinforced concrete for better accuracy and flexibility in application. This paper wants to review, @mpare, and discuss about some flexural toughness of fiber reinforced concrete evaluation methods, such as ACI Commitee 544, ASTM C 1018, CMOD, ASTM C 1399, and also the PCSm method. According to the limitations of the methods mentioned above, the PCSm method is suggested to become a simpler and more appropriate one.
Concrete made with Portland cement has certain characteristics: it is relatively strong in compression but weak in tension and tends to be brittle. These two weaknesses have limited its use. Another fundamental weakness of concrete is that cracks start to form as soon as concrete is placed and before it has properly hardened. These cracks are major cause of weakness in concrete particularly in large on site applications leading to subsequent fracture and failure and general lack of durability. The weakness in tension can be overcome by the use of conventional rod reinforcement and to some extent by the inclusion of a sufficient volume of certain fibers. Fiber reinforced concrete (FRC) may be defined as a composite materials made with Portland cement, aggregate, and incorporating discrete discontinuous fibers. Fiber-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibres that are uniformly distributed and randomly oriented – each of which lend varying properties to the concrete. In addition, the character of fibre-reinforced concrete changes with varying concretes, fibre materials, geometries, distribution, orientation, and densities. In this experimental investigation, an attempt has made to find out strength related tests like Compressive Strength, Split Tensile Strength, Flexural Strength using Pure concrete, steel fibers and Glass Fibers with to volume fraction of 0.0%,0.25%,0.5% , 0.75% and 1% and for aspect ratio and considered for M40 Grade of concrete. The results of the tests showed that the strength properties are enhanced due to addition of glass fibers.