Top PDF Behaviour of Steel Fibre Reinforced Concrete Under Flexural Failure

Behaviour of Steel Fibre Reinforced Concrete Under Flexural Failure

Behaviour of Steel Fibre Reinforced Concrete Under Flexural Failure

professional fields of construction, irrigation works and architecture. There are currently 300,000 metric tons of fibers used for concrete reinforcement. Steel fiber remains the most used fiber of all (50% of total tonnage used) followed by polypropylene (20%), glass (5%) and other fibers (25%) (Banthia, 2012). Steel fiber reinforced concrete under compression and Stress-strain curve for steel fiber reinforced concrete in compression was done by Nataraja.C. Dhang, N. and Gupta, A.P. They have proposed an equation to quantify the effect of fiber on compressive strength of concrete in terms of fiber reinforcing parameter. Mechanical properties of high-strength steel fiber reinforced concrete were done by Song P.S. and Hwang S. They have marked brittleness with low tensile strength and strain capacities of high strength concrete can be overcome by addition of steel fibers. Tdyhey investigated an experimental study were steel fibers added at the volume of 0.5%, 1.0%, 1.5% and 2.0%. The observation indicate that compressive strength of fiber concrete reached a maximum at 1.5%volume fraction, being 15.3% improvement over the HSC. The split tensile and Flexural Strength improved 98.3% and 126.6% at 2.0% volume fraction.
Show more

6 Read more

Fatigue behaviour of steel fibre reinforced concrete – a Review

Fatigue behaviour of steel fibre reinforced concrete – a Review

Makita et al. (2013) studied the tensile fatigue tests on R-UHPFRC elements. Ultra–high performance fibre reinforced concrete (UHPERC) was a Cementitious composite material, it consisting of cement, quartz, sand, silica fume and fibre. It has high compressive strength and high tensile strength of concrete. Single quasi-static load was applied on the specimens. The tensile behavior of UHPFRC was explained by analyzing the force global deformation curve obtained and also improve the load bearing capacity of bridges was glowing due to the increase of traffic loads for more efficient transport industrial product. Finally it is concluded that the steel rebars improve actually the fatigue force bearing capacity of UHPFRC by distributing the applied fatigue stress. Slater et al. (2012) evaluated the shear strength of the steel fibre reinforced concrete (SFRC) beams. The SFRC beams were divided in to six different groups based on their span-depth ratio. Different ranging of steel fibres was used in this study. The shear strength was obtained performing both linear and non-linear regression analysis of each data base. Finally the shear behaviour of SFRC was wider applications in the concrete industry. Many researchers had developed analytical and numerical tools for predicting the shear strength of SFRC beams.
Show more

5 Read more

Behaviour of steel fibre reinforced concrete beams under high rate loading

Behaviour of steel fibre reinforced concrete beams under high rate loading

Abstract. The present study focuses on examining the structural behaviour of steel-fibre-reinforced concrete (SFRC) beams under high rates of loading largely associated with impact problems. Fibres are added to the concrete mix to enhance ductility and energy absorption, which is important for impact-resistant design. A simple, yet practical non-linear finite-element analysis (NLFEA) model was used in the present study. Experimental static and impact tests were also carried out on beams spanning 1.3 meter with weights dropped from heights of 1.5 m and 2.5 m, respectively. The numerical model realistically describes the fully-brittle tensile behaviour of plain concrete as well as the contribution of steel fibres to the post-cracking response (the latter was allowed for by conveniently adjusting the constitutive relations for plain concrete, mainly in uniaxial tension). Suitable material relations (describing compression, tension and shear) were selected for SFRC and incorporated into ABAQUS software Brittle Cracking concrete model. A more complex model (i.e. the Damaged Plasticity concrete model in ABAQUS) was also considered and it was found that the seemingly simple (but fundamental) Brittle Cracking model yielded reliable results. Published data obtained from drop-weight experimental tests on RC and SFRC beams indicates that there is an increase in the maximum load recorded (compared to the corresponding static one) and a reduction in the portion of the beam span reacting to the impact load. However, there is considerable scatter and the specimens were often tested to complete destruction and thus yielding post-failure characteristics of little design value and making it difficult to pinpoint the actual load-carrying capacity and identify the associated true ultimate limit state (ULS). To address this, dynamic NLFEA was employed and the impact load applied was reduced gradually and applied in pulses to pinpoint the actual failure point. Different case studies were considered covering impact loading responses at both the material and structural levels as well as comparisons between RC and SFRC specimens. Steel fibres were found to increase the load-carrying capacity and deformability by offering better control over the cracking process concrete undergoes and allowing the impact energy to be absorbed more effectively compared to conventional RC members. This is useful for impact-resistant design of SFRC beams.
Show more

38 Read more

Flexural Behaviour of Steel Fibre Reinforced Concrete Tunnel Linings

Flexural Behaviour of Steel Fibre Reinforced Concrete Tunnel Linings

The promotion of steel fibre reinforced concrete (SFRC) as a construction material for tunnel linings has prompted a number of researchers to focus on methods of evaluating their flexural strength and stiffness. This thesis presents the results of an experimental and numerical investigation of the flexural behaviour of full-scale steel fibre reinforced concrete tunnel lining segments. A series of a three-point flexure tests were performed to evaluate the maximum load carrying capacity, the load-deformation behaviour and crack propagation characteristics of these segments. The material properties of the steel fibre reinforced concrete were also studied, using both destructive and non-destructive methods. Element compression and tension tests were conducted to characterize the compressive and tensile strength properties of the SFRC. Additionally, computed tomographic scanning was conducted to analyse and estimate the density fraction and fibre orientation of the fibres in SFRC cores. Three-dimensional finite element analyses were conducted to calibrate a concrete damage plasticity constitutive model and provide better understanding of the segment flexural behaviour. The experimental program indicated that the variation in structural performance of the segments was likely due to an inhomogeneity of fibre distribution and orientation. Modifying the numerical model to account for these variations resulted in a more accurate analysis. Furthermore, from the numerical finite element analysis it was found that the non-linear elasto-plastic concrete damage plasticity model in the crack zone of the beam was mesh dependent. Parametric analyses also revealed that the model was particularly sensitive to small changes to the tensile material property input parameters.
Show more

185 Read more

Behaviour of Steel Fibre Reinforced Concrete under Flexural Failure

Behaviour of Steel Fibre Reinforced Concrete under Flexural Failure

The experimental program consists of casting and testing of 3 beams with steel fibers to compare our results with the steel fiber reinforced concrete. The beams used for tests were SFRC beam of size (700 mm x 150 mm x 150 mm) used hook end steel fibers in the concrete for determining flexural strength of concrete . The fiber reinforced concrete beam contains steel fibers in at the rate of 0%, 0.5%, 1%, 1.5% volume fraction of the beams. This experiment requires lots of trail work as I need to find out the maximum strength.
Show more

10 Read more

A Practical Investigation on the Behaviour of Steel Fibre Reinforced Concrete

A Practical Investigation on the Behaviour of Steel Fibre Reinforced Concrete

Cement concrete is the most extensively used construction material in the world. The reason for its extensive use is that it provides good workability and can be moulded to any shape. Ordinary cement concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Internal micro cracks lead to brittle failure of concrete. In this modern age, civil engineering constructions have their own structural and durability requirements. Every structure has its own intended purpose and hence to meet this purpose, modification in traditional cement concrete has become mandatory. It has been found that different type of fibers added in specific percentage to concrete improves the mechanical properties, durability and serviceability of the structure. It is now established that one of the important properties of Steel Fiber Reinforced Concrete (SFRC) is its superior resistance to cracking and crack propagation. In this paper effect of fibers on the strength of concrete for M20 and M40 grade have been studied by varying the percentage of fibers in concrete. Fiber content were varied by 0.50%, 1% and 1.5% by volume of cement. Cubes of size 150mmX150mmX150mm to check the compressive strength and beams of size 500mmX100mmX100mm for checking flexural strength were casted. All the specimens were cured for the period of 7, 28 and 56 days before crushing. The results of fiber reinforced concrete for 3days, 7days and 28days curing with varied percentage of fiber were studied and it has been found that there is significant strength improvement in steel fiber reinforced concrete. The optimum fiber content while studying the compressive strength, flexural strength cube is found to be 1%. Also, it has been observed that with the increase in fiber content up to the optimum value increases the strength of concrete. Slump cone test was adopted to measure the workability of concrete. The Slump cone test results revealed that workability gets reduced with the increase in fiber content.
Show more

5 Read more

Flexural Behaviour of Hybrid Steel Basalt Fibre Reinforced Concrete

Flexural Behaviour of Hybrid Steel Basalt Fibre Reinforced Concrete

numerous micro-cracks. On application of the load, the micro- cracks begin to propagate in the concrete matrix. The addition of randomly spaced discontinuous fibres help in restricting the propagation of the micro-cracks and macro-cracks. Fibres also improve the mechanical properties of plain concrete such as, resistance to impact, resistance to fracture and resistance to dynamic loads [8]. In the modern era, hybridization technology has also been an area of interest to researchers. Hybridization is the process of combining fibers with different characteristics, such as, length, diameter, and aspect ratio, modulus of elasticity, material type and tensile strength, to produce a unique composite that derives benefits from each of the individual fibers [4]. In this study, hybrid fibre reinforced concrete is prepared by combining basalt and steel fibers together according to different volume fraction and aspect ratio. Different experiments were carried out to determine the flexural strength, toughness index and load deflection behaviour of hybrid fibre reinforced beams. For comparison steel fibre reinforced concrete beams and basalt fibre reinforced concrete beams were also casted. All these beams were compared with control beam consisting of no fibres. Key Words: Hybrid fibre reinforced concrete beam, Steel fibre, Basalt fibre.
Show more

5 Read more

Post-cracking tensile behaviour of steel-fibre-reinforced roller-compacted-concrete for FE modelling and design purposes

Post-cracking tensile behaviour of steel-fibre-reinforced roller-compacted-concrete for FE modelling and design purposes

Received 30 May 2016 Accepted 5 October 2016 Available on line 22 March 2017 ABSTRACT: Fracture of steel-fibre-reinforced-concrete occurs mostly in the form of a smeared crack band undergoing progressive microcracking. For FE modelling and design purposes, this crack band could be char- acterised by a stress-strain (σ-ε) relationship. For industrially-produced steel fibres, existing methodologies such as RILEM TC 162-TDF (2003) propose empirical equations to predict a trilinear σ-ε relationship directly from bending test results. This paper evaluates the accuracy of these methodologies and their applicability for roller- compacted-concrete and concrete incorporating steel fibres recycled from post-consumer tyres. It is shown that the energy absorption capacity is generally overestimated by these methodologies, sometimes up to 60%, for both conventional and roller-compacted concrete. Tensile behaviour of fibre-reinforced-concrete is estimated in this paper by inverse analysis of bending test results, examining a variety of concrete mixes and steel fibres. A multi- linear relationship is proposed which largely eliminates the overestimation problem and can lead to safer designs. KEYWORDS: Concrete; Composite; Fibre reinforcement; Metal reinforcement; Waste treatment
Show more

12 Read more

Behaviour of reinforced concrete beams with kenaf and steel hybrid fibre

Behaviour of reinforced concrete beams with kenaf and steel hybrid fibre

Steel fibres have also demonstrated its capability in improving the structural behaviour of reinforced concrete beams (Mansur and Ong, 1991), (Kwak et al., 2002), (Syed Mohsin et al., 2012), (Abbas et al., 2014). Recent studies also suggest that the addition of fibres to reinforced concrete beams with reduced shear reinforcement restores the strength and ductility of the beam (Abbas et al., 2014), (Syed Mohsin et al., 2014). Based on the literature, the study of hybrid fibres (steel and kenaf) to improve the structural behaviour of the reinforced concrete beams and simultaneously serve as part of shear reinforcement in beams has yet been explored. This study attempts at investigating the aforementioned structural properties of a novel hybrid kenaf-steel fibre reinforced concrete.
Show more

6 Read more

Flexural Fatigue Strength of Steel Fibre Reinforced Concrete Containing Blends of Limestone Powder and Silica Fume

Flexural Fatigue Strength of Steel Fibre Reinforced Concrete Containing Blends of Limestone Powder and Silica Fume

Abstract— Based upon the statistical distribution of flexural fatigue life data and flexural fatigue strength of the steel fibre reinforced concrete (SFRC) containing blends of limestone powder (LP) and silica fume (SF), the influence of these inserts on the flexural fatigue performance of concretes is probed. Concrete mixes were proportioned to replace 30% cement with these mineral inserts in different trends. The flexural fatigue performance of plain concrete (PC) and SFRC of comparable fibre size, as reported in previous studies is made to compare with the fatigue performance of present mixes to demonstrate the effect of addition of LP and SF as partial replacement of cement. It has been ascertained that distribution of fatigue life of concretes under study can be modeled by two-parameter Weibull distribution. The increased values of shape parameter for concretes containing mineral inserts correspond to its more homogenous micro- structure as compared to control concrete. The pozzolanic and filler effect of SF in the cement improves the bulk matrix and strengthens the interfaces between fibre and cement paste and aggregate and cement paste. The modified pore structure of LP based concretes is attributed to its filler effect. The fatigue life data has also been presented in the form of S-N diagram and the two-million cycles fatigue strength/endurance limit for mixes was estimated.
Show more

10 Read more

Behaviour of High Performance Fibre Reinforced Concrete Beam under Cyclic Loading

Behaviour of High Performance Fibre Reinforced Concrete Beam under Cyclic Loading

Abstract—This paper explores the cyclic behaviour of the high performance concrete and also describes influence of steel fibres in the HPC beams. The high performance concrete mix with M60 grade was designed using ACI 2411.4R. An experimental investigation of the behaviour of HPC beams reinforced with normal steel bars and steel fibres under cyclic loading is tested and the results are presented in this paper. In this study 9 R.C.C beams were casted using high performance concrete, which includes control beam that consists of normal mix without steel fibres. And remains R.C.C beams consists of two different volume fractions (0.75% and 1%) of steel fibres with two different aspect ratio ( 60 and 50). All beams were tested under full cyclic load to establish load-deflection curve and the results were evaluated. The results also show that inclusion of steel fibres intensify the ductility, Stiffness and residual strength. Inclusion of steel fibres has proven to resist the stiffness degradation after applying four number of cyclic loading on the HPC beam.Studies revealed that, the use of fibres in concrete for the construction purpose to decrease the cracks as well as strength.
Show more

5 Read more

Experimental Study On Flexural Behaviour Of Hybrid Fibre Reinforced Concrete Member

Experimental Study On Flexural Behaviour Of Hybrid Fibre Reinforced Concrete Member

Concrete is acknowledged to be a relatively brittle material when subjected to normal stresses and impact loads, where tensile strength is only approximately one tenth of its compressive strength. As a result of these characteristics, concrete member could not support such loads and stresses that usually take place, majority on concrete beams and slabs. Historically, concrete member reinforced with continuous reinforcing bars, withstand tensile stresses and compensate for the lack of ductility and strength. Furthermore, steel reinforcement is adopted to overcome high potentially tensile stresses and shear stresses at critical location in concrete member. The additional of steel reinforcement significantly increase the strength of concrete, but to produce concrete with homogenous tensile properties, the development of micro cracks is a must to suppress. The introduction of fibres was brought in as a solution to develop concrete in view of enhancing its flexural and tensile strength, which are a new form of binder that could combine Portland cement in the bonding with cement matrices. Fibres are most generally discontinuous, randomly distributed throughout the cements matrices. The term ‘Fibre Reinforced Concrete’ (FRC) is made up with cement, various sizes of aggregates, which incorporate with discrete, discontinuous fibres.
Show more

10 Read more

A Detailed Experimental Study on The Flexural Behaviour of Concrete Filled Steel Tube Beams

A Detailed Experimental Study on The Flexural Behaviour of Concrete Filled Steel Tube Beams

Concrete filled steel tubes (CFST) member have many advantages compared with the ordinary structural member made of steel or reinforced concrete. One of the main advantages is the interaction between the steel tube and concrete. Concrete delays the steel tube’s local buckling, whereas the steel tube confines the concrete and thereby increases the concrete’s strength. CFSTs are economical and permit rapid construction because the steel tube serves as formwork and reinforcement to the concrete fill, negating the need for either. The deformation capacity of the system is increased by the combined action of the concrete fill with the thin, ductile steel tube. The concrete fill significantly increases inelastic deformation capacity and the compressive stiffness and load capacity of the CFST member. In building construction concrete filled steel tubes are very widely used for columns in combination with steel or reinforced concrete beam. In this work totally 9 specimens were tested out of which 3 specimens were empty steel tubes and remaining 6 specimens were concrete filled with different bonding techniques. As it is prefabricated time consumption will be less in construction practice and due to confinement more ductility is expected which is very useful in earthquake resistant structures. Load carrying capacity of CFST almost doubled in comparison with empty steel tubes. Ultimate load carrying capacity of concrete filled steel tube beams almost doubled compared to empty steel tubes. Compared to empty steel tubes, strength increase of 67.19%, 97.48% and 114.84% was observed in normal CFST, CFST with sand blasting and CFST with diagonal shear connector beams respectively. Average ultimate load of EST was 105.66kN whereas average load of CFSTB, CFSTBWSB and CFSTBWDSC was 176.66, 208.66 and 227kN respectively. The maximum load was taken by the specimen CFSTBWDSC – 03 which was 231kN, it may be because of presence of diagonal shear connector inside the tube.
Show more

8 Read more

Improving Structure Integrity with Fibre Reinforced Concrete

Improving Structure Integrity with Fibre Reinforced Concrete

Steel fibre-reinforced concrete is normally cheaper and easier than any other fibres to use a form of standard reinforced concrete. Commonly used reinforced concrete utilises steel bars that are placed in the liquid cement, which requires a great potential of preparation work but results in making much durable concrete. Steel fibre-reinforced concrete uses fibres which are thin and similarly uses wires made up of steel to mixed in with the cement. This force the concrete with much greater structural strength reduces cracking, other failures and helps protect against extreme cold.
Show more

5 Read more

Flexural strength of basalt fibre reinforced recycled aggregate concrete

Flexural strength of basalt fibre reinforced recycled aggregate concrete

Basalt fibers have ability to reduce cracking nature in the beam and have more stiffness while using these fibers compared to without addition of fibers (NAC-0). The ultimate load carrying capacity of recycled aggregate concrete without addition fibers are increase along with more deflections. This inference the incorporation fibres show the ductility property to the concrete. The fibres should act as crack arresters and post crack behaviour is varying when compared with plane mixes. Among all mixes the mix with 50% RAC showed effective carrying capacity both in load and deflection. The mix with 25% RAC shown a clink at one point in the Figure 4(a), this may due to some experimental error during experimentation.
Show more

8 Read more

Fracture Properties of Mixed Mode Steel Fibre Reinforced Concrete

Fracture Properties of Mixed Mode Steel Fibre Reinforced Concrete

There are three modes of fracture failure: 1) Mode I 2)Mode II 3)Mode III.Mode I Opening or tensile mode, where the crack surfaces move directly apart.Mode II Sliding or in- plane shear mode, where the crack surfaces slide over one another in a direction perpendicular to the leading edge of the crack. Mode III Tearing or anti-plane shear mode, where the crack surfaces move relative to one another and parallel to the leading edge of the crack. Mode-I fracture is a clear type of crack propagation in fiber reinforced concrete. Mode-II and III are complex failure modes. In these modes the stress normal to the crack surface needs to be approximately zero and only in-plane shear stress should exist. Even when these conditions can be realized, a combination of different stresses exist (shear, tension, compression and bending) over the crack surface.
Show more

6 Read more

A Study on Flexural Behaviour of Concrete Filled Steel Tubes

A Study on Flexural Behaviour of Concrete Filled Steel Tubes

Concrete filled steel tubes (CFST) member have many advantages compared with the ordinary structural member made of steel or reinforced concrete. One of the main advantages is the interaction between the steel tube and concrete. Concrete delays the steel tube‟s local buckling, whereas the steel tube confines the concrete and thereby increases the concrete‟s strength. CFSTs are economical and permit rapid construction because the steel tube serves as formwork and reinforcement to the concrete fill, negating the need for either. The deformation capacity of the system is increased by the combined action of the concrete fill with the thin, ductile steel tube. The concrete fill significantly increases inelastic deformation capacity and the compressive stiffness and load capacity of the CFST member. In this work totally 9 specimens were tested out of which 3 specimens were empty steel tubes and remaining 6 specimens were concrete filled with different bonding techniques. As it is prefabricated time consumption will be less in construction practice and due to confinement more ductility is expected which is very useful in earthquake resistant structures. Load carrying capacity of CFST almost doubled in comparison with empty steel tubes. Ultimate load carrying capacity of concrete filled steel tube beams almost doubled compared to empty steel tubes. Compared to empty steel tubes, strength increase of 67.19%, 97.48% and 114.84% was observed in normal CFST, CFST with sand blasting and CFST with diagonal shear connector beams respectively. Average ultimate load of EST was 105.66kN whereas average load of CFSTB, CFSTBWSB and CFSTBWDSC was 176.66, 208.66 and 227kN respectively. The maximum load was taken by the specimen CFSTBWDSC – 03 which was 231kN, it may be because of presence of diagonal shear connector inside the tube.
Show more

6 Read more

Effect of Dosage, Aspect Ratio and End Shape of Steel Fibers on the Flexural Toughness Performance of Steel Fiber Reinforced Concrete- A Performance Study

Effect of Dosage, Aspect Ratio and End Shape of Steel Fibers on the Flexural Toughness Performance of Steel Fiber Reinforced Concrete- A Performance Study

Apart from the compression, tensile and flexural strength properties fiber reinforced concrete has been widely implemented because of its post cracking behavior i.e., after the sudden release of energy at the first crack level. Toughness is defined as the area under a load-deflection (or stress-strain) curve. Adding fibres to concrete greatly increases the toughness of the material. That is, fibre-reinforced concrete is able to sustain load at deflections or strains much greater than those at which cracking first appears in the matrix.
Show more

10 Read more

Experimental Investigations on The Flexural Strength of PET Reinforced Concrete

Experimental Investigations on The Flexural Strength of PET Reinforced Concrete

In the above Figure.8, a comparison between control beam(CB), beam reinforced with steel(RSB) and beam reinforced with only two PET hollow bars (RP2B) is done, which depicts the deflection of these beams under their corresponding loading. The deflection of RP2B has similar variation compared to RSB in exhibiting a large deformation before failure than the control beam which exhibited sudden failure. The load at failure for RSB is greater than that of CB and RP2B. Just before failure, the RP2B exhibited a little ductile nature like RSB. Due to improper bonding between concrete and PET, micro cracks would have propagated in concrete and the failure has occured in earlier stage itself, but the post cracking behaviour of RP2B shows the ductile nature of PET in the beam offering a little resistance even after the failure of beam preventing sudden failure.
Show more

8 Read more

The effect of fibres on the properties of concrete with oil contaminated sand

The effect of fibres on the properties of concrete with oil contaminated sand

The addition of fibres in oil-impacted concrete may be the compensation solution for this known reduction in concrete strength. Concrete is acknowledged to be a relatively brittle material when subjected to normal stresses and impact loads, where tensile strength is only approximately one tenth of its compressive strength. The introduction of fibres is offered as a solution to modify and enhance the mechanical properties and behaviour of concrete in its applications. Fibre-reinforced concrete (FRC) can enhance impact, abrasives, durability, vibration and specifically crack control properties that ordinary Portland cement (OPC) concrete does not possess (Maccaferri 2015). Fibres are most generally discontinuous, randomly distributed throughout the cement matrices. They vary in types, geometry, properties and availability in the construction industry (Døssland 2008). The most common are polypropylene fibres, steel fibres and glass fibres (Figure 1.3). The effects of the addition of these types of fibres on the properties of concrete with oil contaminated sand will be investigated in this study.
Show more

183 Read more

Show all 10000 documents...