Bond characteristics of steel fibre reinforced self-compacting concrete

2012 ◽  
Vol 39 (7) ◽  
pp. 834-848 ◽  
Author(s):  
Farhad Aslani ◽  
Shami Nejadi

Steel fibre reinforced self-compacting concrete (SFRSCC) is a relatively new composite material that combines the benefits of the self-compacting concrete (SCC) technology with the advantages derived from the fibre addition to a brittle cementitious matrix. Steel fibres improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibres on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fibre and SCC. Based on the available experimental results, the current analytical steel fibre pullout model is modified by considering the different SCC properties and different fibre types (smooth, hooked) and fibre inclination. To take into account the effect of fibre inclination in the pullout model, apparent shear strengths (τ(app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (ϕ).

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Srinivasan Karunanithi

The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness.


2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Joseph Abah Apeh ◽  
Juliet Eyum Ameh

Self-compacting concrete (SCC) has great potentials as it offers several environmental, economic and technical benefits. Moreover, the use of fibers extends its possibilities since fibers arrest cracks and retard their propagation. Incorporation of Quarry Dust (QD) in SCC help to reduce environmental hazards during the production of QD. This study evaluated the fresh and hardened properties of steel fiber self-compacting concrete (SFSCC) incorporating QD. The optimum fiber and QD contents with no adverse effects on fresh and hardened properties were determined. A comparative study on behavior of SCC and SFSCC mixtures in terms of workability, compressive strength, compressive strength development ratio, tensile, flexural and energy absorption capacity was carried out. Test results showed that compressive strength increased with increase in QD contents at fixed fiber content by mass of Portland cement (PC) and then decreased. Strength development ratio (C28/C7) for SCC was 1.13, while it was 1.06, 1.08, 1.10 and 1.01 after reinforcing with 0.10, 0.20 and 0.30 contents of fiber. The compressive, tensile, flexural and energy absorption capacity or Toughness of SFSCC increased with the inclusion of the aforementioned contents of steel fiber up to 0.20 % volume of total binder at constant QD content and then decreased when compared with control SCC values. From these results, optimum value for the variables studied was obtained from mix QD20 + 0.2fr. Hence, steel fiber and QD could be successfully used in SCC production not minding the slight draw back on workability of SCC caused by inclusion of steel fiber, but with a modified dosage of super-plasticizer (SP), fresh and hardened properties, in accordance with specifications in relevant code(s) can be achieved.


2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Juli Asni Lamide ◽  
Roslli Noor Mohamed ◽  
Ahmad Baharuddin Abd Rahman

This paper presents an experimental test program that was carried out to investigate the shear performance of steel fibre self-compacting concrete (SFSCC) beams. In this paper, the mechanical performance of results from all mixtures used to cast normal concrete (NC), self-compacting concrete (SCC) and steel fibre self-compacting concrete (SFSCC) were also investigated. In total, 27 cubes, 9 cylinders, 9 prisms and 9 beams were prepared for the assessment of mechanical properties of three different mixtures. Four beams (125 mm x 250 mm x 2200 mm) were tested and cast using three different concrete mixtures, having two different spacing of stirrups as a result of 50% reduction of the stirrups amount. Three beams with different mixtures having similar stirrups spacing 125mm while the fourth beam with SFSCC mixes having 250mm stirrups spacing. The results show that the mechanical properties were positively affected with steel fibres inclusion. The addition of steel fibres showed an increment up to 40% in the shear load capacity for B-SFSCC125 compared to B-NC125 and B-SCC125.  In addition, the crack pattern of B-SFSCC was found better than B-NC and B-SCC.   


2012 ◽  
Vol 2 (3) ◽  
Author(s):  
Farhad Aslani ◽  
Shami Nejadi

AbstractSteel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fiber and SCC firstly. Based on the available experimental results, the current analytical steel fiber pullout model (Dubey 1999) is modified by considering the different SCC properties and different fiber types (smooth, hooked) and inclination. In order to take into account the effect of fiber inclination in the pullout model, apparent shear strengths (τ (app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (ϕ). Furthurmore, steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of steel fibers. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components containing reinforcement and steel fibers, information is hardly available in this area. In this study, bond characteristics of deformed reinforcing steel bars embedded in SFRSCC is investigated secondly.


2016 ◽  
Vol 1133 ◽  
pp. 254-258
Author(s):  
Hafizan Hashim ◽  
Amir Radzi Ab Ghani ◽  
Hafizi Lukman ◽  
N.V. David

A conventional tube is considered in oblique position when its longitudinal is oblique. However, oblique attachments vary as the tube can be a straight or angulated tube. In the present study, impact responses of different oblique positioned tubes subject to axial loading were numerically studied. Next, the best oblique arrangements were proposed that have higher critical load angle and energy absorption capacity. Results show that specimen of Top-Bottom Angulated (TBA) from horizontal is the best choice for its lowest initial peak load and mean crush load. This data therefore has great potential for further enhance the new design of energy absorbers in oblique position.


The aim of this study is to examine the effect of fiber mat’s density and deformation mechanism of tubes with and without die compression. In this study a new mode of deformation mechanism of density graded GFRP circular tube is examined when they are subjected to axial compression on to a die and without die to examine its energy absorbing capacity. Theoretical calculations were made to predict the crushing stress of different specimens. It is observed that increasing density of fiber increases energy absorption value but decreases the specific energy absorption and the die could trigger progressive crushing additionally decreasing peak load. Here the compressed tube wall is compelled to be deformed towards the end of compression die with a little range of bending curvature which was forced by the radius of the die at high crushing stress and the major part of the deformation takes place at a nearly constant load, which leads to high energy absorption capacity. Comparison between theoretical prediction values by derived equations and the experimental results shows good correlation.


2020 ◽  
Vol 40 (7) ◽  
pp. 615-627
Author(s):  
Mohd Kamal Mohd Shah ◽  
Yeo Kiam Beng ◽  
Sanjay Mohan ◽  
Mohd Nizam Husen ◽  
Irma Othman ◽  
...  

AbstractPultrusion is considered to be a cost efficient method for developing composite structures. It facilitates the fabrication of uniform cross-section products with improved fiber alignment, mechanical properties, good surface characteristics, etc. In order to ascertain the crashworthiness, the pultruded composites shall be able to resist impact loads, and in this concern, the energy absorption capacity of the pultruded composites must be explored. This article presents the experimental and numerical investigation of the crushing behavior of polyester based pultruded composite with rectangular cross section. Pultruded rectangular tubes with e-glass/polyester composites have been developed for this study. The cross-section of the tubes was developed into two triggering profiles, the uniform edge around the section and the tulip pattern. The tubes were subjected to impact loads, and the effect of these triggering profiles on the energy absorption capacity of the tubes has been investigated. The testing of all composites has been carried out at three different impact velocities (10, 20 and 45 mm/min). The results have revealed the dependence of crushing behavior of the tubes on the loading velocity and the triggered profiles. Lower peak load and high specific energy absorption (SEA) was observed in the tube with tulip pattern profile. The results obtained from the simulation have also shown consistency with the real-time experiments.


2020 ◽  
Vol 313 ◽  
pp. 00038
Author(s):  
Martin Lišovský ◽  
Dalibor Kocáb ◽  
Petr Žítt ◽  
Dominik Wünsche

The paper deals with testing of self-compacting concrete slabs with scattered steel reinforcement, which are designed for the production of garden furniture or benches. A self-compacting concrete was designed for the experiment and its composition was further modified by the addition of steel fibres. Plain self-compacting concrete was used to produce test specimens with nominal dimensions of 40×40×160 mm, which were used to determine the basic properties of concrete, and test slabs for experimental analysis of their behaviour under load. The self-compacting concrete with steel fibres was only used to produce test slabs. The slabs were loaded in three different ways, of which one was to simulate real loading of the horizontal part of a concrete bench. The results of the loading tests are compared to the results of a nonlinear numerical analysis conducted using the finite element method.


2019 ◽  
Vol 31 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Farhad Aslani ◽  
Yinong Liu ◽  
Yu Wang

Self-compacting concrete presents good workability to fill complicated forms without mechanical vibrations. This concrete is often reinforced with fibres to improve the strength and toughness. This study investigated the use of nickel -titanium (NiTi) shape memory alloy fibres in comparison with polypropylene and steel fibres in self-compacting concrete. The performances of the fresh fibre–reinforced self-compacting concrete are explored by slump flow and J-ring experiments. Meanwhile, the static and cyclic flexural tests are conducted to estimate the bending resistance strength performance, residual deformation and recovering capacity of shape memory alloy, polypropylene and steel fibre–reinforced self-compacting concrete. Moreover, the flexural toughness of the shape memory alloy, polypropylene and steel fibre–reinforced self-compacting concrete is calculated using four different codes. The shape memory alloy fibre–reinforced self-compacting concrete with 0.75% volume fraction presents the largest flexural strength, re-centering ability and toughness in comparison with polypropylene and steel fibre–reinforced self-compacting concretes. The experimental results demonstrated the beneficial influence of the shape memory and superelastic properties of NiTi in postponing initial crack formation and restricting the crack widths.


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