BOND BEHAVIOR OF LIGHTWEIGHT FIBER REINFORCED CONCRETE

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Klaus Holschemacher ◽  
Ahsan Ali ◽  
Shahid Iqbal
Keyword(s):  
Reinforced Concrete ◽  
Lightweight Concrete ◽  
Normal Weight ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Normal Weight Concrete ◽  
Air Content ◽  
Pull Out

In construction industry lightweight concrete and fiber reinforced concrete are being used for many years. The former is known for brittle nature, light in weight and low thermal conductivity properties. It also offers better workability when compared to the normal weight concrete for the same slump value. These properties are however affected by addition of discrete fibers. Among the affected properties is also the bond between steel and concrete surrounding it. The integrity of a reinforced concrete member is not ensured in the absence of adequate bond. Due to limited literature on the subject matter, an experimental program was carried out to understand the bond behavior in lightweight concrete after fiber inclusion. For the purpose modified pull-out specimens made of Lightweight Fiber Reinforced Concrete (LWFC) were tested. Hooked end steel fibers having length 35 mm and diameter 0.5 mm (l/d = 0.7) were incorporated in dosages of 0, 20, and 40 kg/m3. Besides pull-out specimens, testes were also carried out for fresh and hardened properties of LWFC. Tests results indicate higher pull-out loads for higher fiber contents. The average increase in ultimate bond strength was observed at 28% and 2% for 40 kg/m3 and 20 kg/m3 fiber contents respectively. The fresh concrete density, compressive strength of mixes reduced and air-content values increased with increase in fiber content.

scholarly journals Comparison of Mechanical Properties of Lightweight and Normal Weight Concretes Reinforced with Steel Fibers

2018 ◽  
Vol 8 (2) ◽  
pp. 2741-2744
Author(s):  
A. Ali ◽  
Z. Soomro ◽  
S. Iqbal ◽  
N. Bhatti ◽  
A. F. Abro
Keyword(s):  
Reinforced Concrete ◽  
Strength Class ◽  
Lightweight Concrete ◽  
Normal Weight ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Hardened Concrete ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
Concrete Properties

Compared to conventional concrete, lightweight concrete is more brittle in nature however, in many situations its application is advantageous due to its lower weight. The associated brittleness issue can be, to some extent, addressed by incorporation of discrete fibers. It is now established that fibers modify some fresh and hardened concrete properties. However, evaluation of those properties for lightweight fiber-reinforced concrete (LWFC) against conventional/normal weight concrete of similar strength class has not been done before. Current study not only discusses the change in these properties for lightweight concrete after the addition of steel fibers, but also presents a comparison of these properties with conventional concrete with and without fibers. Both the lightweight and conventional concrete were reinforced with similar types and quantity of fibers. Hooked end steel fibers were added in the quantities of 0, 20, 40 and 60kg/m3. For similar compressive strength class, results indicate that compared to normal weight fiber-reinforced concrete (NWFC), lightweight fiber-reinforced concrete (LWFC) has better fresh concrete properties, but performs poorly when tested for hardened concrete properties.

scholarly journals Using Steel Fiber-Reinforced Concrete Precast Panels for Strengthening in Shear of Beams: An Experimental and Analytical Investigation

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Pitcha Jongvivatsakul ◽  
Linh V. H. Bui ◽  
Theethawachr Koyekaewphring ◽  
Atichon Kunawisarut ◽  
Narawit Hemstapat ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Simple Formulation

In this paper, the performances of reinforced concrete (RC) beams strengthened in shear with steel fiber-reinforced concrete (SFRC) panels are investigated through experiment, analytical computation, and numerical analysis. An experimental program of RC beams strengthened by using SFRC panels, which were attached to both sides of the beams, is carried out to investigate the effects of fiber volume fraction, connection type, and number and diameter of bolts on the structural responses of the retrofitted beams. The current shear resisting model is also employed to discuss the test data considering shear contribution of SFRC panels. The experimental results indicate that the shear effectiveness of the beams strengthened by using SFRC panels is significantly improved. A three-dimensional (3D) nonlinear finite element (FE) analysis adopting ABAQUS is also conducted to simulate the beams strengthened in shear with SFRC panels. The investigation reveals the good agreement between the experimental and analytical results in terms of the mechanical behaviors. To complement the analytical study, a parametric study is performed to further evaluate the influences of panel thickness, compressive strength of SFRC, and bolt pattern on the performances of the beams. Based on the numerical and experimental analysis, a shear resisting model incorporating the simple formulation of average tensile strength perpendicular to the diagonal crack of the strengthened SFRC panels is proposed with the acceptable accuracy for predicting the shear contribution of the SFRC system under various effects.

A study of some factors affecting the fiber–matrix bond in steel fiber reinforced concrete

1990 ◽  
Vol 17 (4) ◽  
pp. 610-620 ◽  
Author(s):  
Nemkumar Banthia
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Factors Affecting ◽  
Surrounding Matrix ◽  
Pull Out ◽  
Fiber Matrix

With the objective of understanding the reinforcing mechanisms of fibers in steel fiber reinforced concrete, the bond between the fibers and the surrounding matrix is studied by conducting single fiber pull-out tests on fibers bonded in cementitious matrices. Various matrix compositions and fiber geometries have been investigated and the effects of various other factors on the pull-out behavior of the fibers have been quantified through pull-out load–extension plots. Finally, the various modes of fiber–matrix load transfer have been discussed and the favorable and unfavorable conditions for such a transfer have been recognized. Key words: steel fiber reinforced concrete, toughness, fiber–matrix bond, deformed fiber, pull-out tests, load–extension plots.

scholarly journals Computational and Simulation Analysis of Pull-Out Fiber Reinforced Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xia Zhao ◽  
Xiong-Jun He ◽  
Sheng Yan ◽  
Nguyen Phan Anh
Keyword(s):  
Reinforced Concrete ◽  
Simulation Analysis ◽  
Constant Load ◽  
Fiber Reinforced Concrete ◽  
Von Mises Stress ◽  
Fiber Reinforced ◽  
Resin Layer ◽  
Pull Out ◽  
Von Mises ◽  
Rupture Mode

The computational and simulation analysis of pull-out fiber reinforced concrete was investigated. The finite element analysis was used to make this modeling and analysis on this reinforced system and three parts (concrete matrix, the placed fiber reinforcement polymers (FRP), and resin layer) were studied. A constant load was directly applied on the free end of placed FRP and the deformation, von Mises stress, displacement, and strain of these three analyzed parts were obtained. Meanwhile, the specimen system of bonding strength and strain was calculated by the method of ABAQUS. The results showed that, with the constant load, the von Mises stress, deformation, and strain appeared in these three parts, and the maximum values in both FRP and resin layer were shown at the free end side, which provides an accurate description of the rupture mode.

scholarly journals Analysis of Fiber-Reinforced Concrete Slabs under Centric and Eccentric Load

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7152
Author(s):  
Zuzana Marcalikova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda ◽  
Radim Cajka
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Concrete Slabs ◽  
Detailed Knowledge ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
3D Deformation

Research on the interaction between slabs and subsoil involves the field of materials engineering, concrete structures, and geotechnics. In the vast majority of cases, research focuses on only one of these areas, whereas for advanced study and computer simulations, detailed knowledge of the whole task is required. Among the new knowledge and information upon which this article focuses is the evaluation of subsoil stress using specialized pressure cells, along with detailed measurements of the deformation of a fiber-reinforced concrete slab. From a design point of view, this research is focused on the issue of the center of the cross section and the influence of eccentricity. Knowledge in this area is not yet comprehensively available for fiber-reinforced concrete slabs, where 2D deformation sections of the slab and 3D deformation surfaces of the slab are used in experiments. The experimental program includes a centrically and eccentrically loaded slab. These are structural elements that were tested on a specialized device. Both slabs had the same concrete recipe, with a dispersed reinforcement content of 25 kg/m3. The dimensions of the slab were 2000 × 2000 × 150 mm. Laboratory tests assessed compressive strength, the modulus of elasticity, splitting tensile strength, and bending tensile strength. Based on approximate data from the 3D deformation surfaces, an evaluation of the load-displacement diagrams for the center of the slab and for the center of eccentricity was performed. In conclusion, an overall evaluation and discussion of the results relies on experiments and the mechanical properties of fiber-reinforced concrete.

scholarly journals Towards Innovative and Sustainable Construction of Architectural Structures by Employing Self-Consolidating Concrete Reinforced with Polypropylene Fibers

2020 ◽  
Author(s):  
Wael Zatar ◽  
Hai Nguyen
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Sustainable Construction ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Self Consolidating Concrete ◽  
Air Content ◽  
Slump Flow ◽  
Architectural Structures

Self-consolidating concrete (SCC) has been successfully employed to reduce construction time and enhance the quality, performance, and esthetic appearance of concrete structures. This research aimed at developing environmentally friendly fiber-reinforced concrete (FRC) consisting of SCC and recycled polypropylene (PP) fibers for sustainable construction of city buildings and transportation infrastructure. The addition of the PP fibers to SCC helps reducing shrinkage cracks and providing enhanced mechanical properties, durability, and ductility of the concrete materials. Several mix designs of self-consolidating fiber-reinforced concrete (SCFRC) were experimentally examined. Material and esthetic properties of the SCFRC mixtures that include micro silica, fly ash, and PP fibers were evaluated. Trial-and-adjustment method was employed to obtain practically optimum SCFRC mixtures, mixtures that are affordable and easy to make possessing enhanced compressive strength and esthetic properties. Slump flow and air content testing methods were used to determine the fresh properties of the SCFRC mixtures, and the esthetic properties of the mixtures were also evaluated. The hardened properties of the SCFRC mixtures were examined using three- and seven-day compression tests. The amount of fine/coarse aggregate, water, and other admixtures were varied while the Portland cement content in all mixtures was maintained unchanged. The maximum three-day compressive strength was 43.17 MPa and the largest slump flow was 736.6 mm. Test results showed enhanced material properties such as slump flow, air content and compressive strength values of the SCFRC mixtures and their excellent esthetic appearance. The favorable seven-day compressive strength of the SCFRC mixture, with 4.8 percent air content and 660.4 mm slump flow, is 39.26 MPa. The mixtures’ in this study are proven to be advantageous for potential SCFRC applications in architectural structures including building façades and esthetically-pleasing bridges.

Anchorage Capacity of Headed Bars in Steel Fiber Reinforced Concrete

2021 ◽  
Author(s):  
Payal Sachdeva ◽  
A.B. Danie Roy ◽  
Naveen Kwatra
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Failure Modes ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Concrete Compressive Strength ◽  
Pull Out

Headed bars (HB) with different head shapes (Square, Circular, and Rectangular) and bar diameters (db: 16, 20, and 25 mm) embedded in steel fiber reinforced concrete have been subjected to pull-out test. The influence of head shapes, concrete compressive strength (M20 and M40), db, and steel fibers (0, 0.5, 1, and 1.5%) on the anchorage capacity of HB have been evaluated. Numerical model for improving the anchorage capacity of HB has also been proposed. Results have revealed that the anchorage capacity of HB increases with the increase in concrete compressive strength, db, and steel fibers, which have been validated by non-linear regression analysis using dummy variables. Two failure modes namely, steel and concrete-blowout have been observed and the prevailing mode of failure is steel failure. Based on load-deflection curves and derived descriptive equations, it is observed that the circular HB has displayed the highest peak load.

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