Bond between epoxy-coated reinforcing bars and concrete under impact loading

1994 ◽  
Vol 21 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Cheng Yan ◽  
Sidney Mindess
Keyword(s):  
Reinforced Concrete ◽  
Strain Rate ◽  
Fracture Energy ◽  
Impact Loading ◽  
Steel Fibre ◽  
Bond Stress ◽  
Fibre Reinforced Concrete ◽  
Reinforcing Bars ◽  
Polypropylene Fibres ◽  
Steel Fibres

The bond between epoxy-coated reinforcing bars and concrete under static, high strain rate, and impact loading was studied for plain concrete, polypropylene fibre reinforced concrete, and steel fibre reinforced concrete. The bond stress, slip, crack development, the bond stress–slip relationship, and the fracture energy during the bond-slip process were investigated experimentally. The results were compared with those for uncoated reinforcing bars. It was found that for epoxy-coated rebars, the bond resistance decreased, in terms of the maximum local bond stress and the average bond stress; wider cracks developed during the bond process; and the fracture energy during bond failure decreased. It was also found that the influence of epoxy coating on the bond behaviour for push-in loading was much more significant than for pull-out loading. However, steel fibre additions at a sufficient content, and higher concrete strength, can mitigate the above effects to a considerable degree. Polypropylene fibres were much less effective in this regard than steel fibres. Key words: epoxy-coated rebars, bond, fibre concrete, strain rate, impact steel fibres, polypropylene fibres, concrete, high strength concrete.

Effect of Fibres on Bond Behaviour Under Impact Loading

1990 ◽  
Vol 211 ◽  
Author(s):  
Cheng Yan ◽  
Sidney Mindess
Keyword(s):  
Impact Loading ◽  
Steel Fibre ◽  
Polypropylene Fibre ◽  
Reinforcing Bars ◽  
Polypropylene Fibres ◽  
Bond Behaviour ◽  
Steel Fibres

AbstractThe bond between concrete and reinforcing bars under impact loading was studied for plain, polypropylene fibre reinforced, and steel fibre reinforced concretes. It was found that adding steel fibres significantly improved the bond behaviour under impact loading; polypropylene fibres had a much smaller effect.

scholarly journals Experimental Investigation of Shear Strength for Steel Fibre Reinforced Concrete Beams

2021 ◽  
Vol 15 (1) ◽  
pp. 81-92
Author(s):  
Constantinos B. Demakos ◽  
Constantinos C. Repapis ◽  
Dimitros P. Drivas
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Steel Fibre ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete

Aims: The aim of this paper is to investigate the influence of the volume fraction of fibres, the depth of the beam and the shear span-to-depth ratio on the shear strength of steel fibre reinforced concrete beams. Background: Concrete is a material widely used in structures, as it has high compressive strength and stiffness with low cost manufacturing. However, it presents low tensile strength and ductility. Therefore, through years various materials have been embedded inside it to improve its properties, one of which is steel fibres. Steel fibre reinforced concrete presents improved flexural, tensile, shear and torsional strength and post-cracking ductility. Objective: A better understanding of the shear performance of SFRC could lead to improved behaviour and higher safety of structures subject to high shear forces. Therefore, the influence of steel fibres on shear strength of reinforced concrete beams without transverse reinforcement is experimentally investigated. Methods: Eighteen concrete beams were constructed for this purpose and tested under monotonic four-point bending, six of which were made of plain concrete and twelve of SFRC. Two different aspect ratios of beams, steel fibres volume fractions and shear span-to-depth ratios were selected. Results: During the experimental tests, the ultimate loading, deformation at the mid-span, propagation of cracks and failure mode were detected. From the tests, it was shown that SFRC beams with high volume fractions of fibres exhibited an increased shear capacity. Conclusion: The addition of steel fibres resulted in a slight increase of the compressive strength and a significant increase in the tensile strength of concrete and shear resistance capacity of the beam. Moreover, these beams exhibit a more ductile behaviour. Empirical relations predicting the shear strength capacity of fibre reinforced concrete beams were revised and applied successfully to verify the experimental results obtained in this study.

Estimation of fracture energy of high-strength steel fibre-reinforced concrete using rule-based Mamdani-type fuzzy inference system

2012 ◽  
Vol 19 (4) ◽  
pp. 373-380 ◽  
Author(s):  
Fuat Köksal ◽  
Yuşa Şahin ◽  
Ahmet Beycioğlu ◽  
Osman Gencel ◽  
Witold Brostow
Keyword(s):  
Reinforced Concrete ◽  
Fracture Energy ◽  
Fuzzy Inference System ◽  
Steel Fibre ◽  
Fuzzy Inference ◽  
Experimental Results ◽  
Approximate Reasoning ◽  
Fibre Reinforced Concrete ◽  
Inference System ◽  
Steel Fibre Reinforced Concrete

AbstractIn this study, we worked to estimate the fracture energy of steel fibre-reinforced concrete (SFRC) according to the water/cement ratio (w/c), tensile strength of steel fibre, steel fibre volume fraction and flexural strength of concrete sample as inputs using the Mamdani-type fuzzy inference system (FIS). In the study, the values obtained from the model and experimental divided three groups (each group has six experimental results) according to the w/c ratios to evaluate the fuzzy logic (FL) model approximate reasoning ability. As a result, the Mamdani-type FIS has shown a satisfying relation with the experimental results and suggests an alternative approach to evaluate the fracture energy estimation using related inputs.

Mechanical Properties and Fracture Energy of Concrete Beams Reinforced with Basalt Fibres

2022 ◽  
Author(s):  
Ana Caroline Da Costa Santos ◽  
Paul Archbold
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Fracture Energy ◽  
Mechanical Performance ◽  
Plain Concrete ◽  
Natural Fibre ◽  
Bending Test ◽  
Natural Material ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres

Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fibre types being used for different applications. Typically, steel fibres give additional tensile strength to the mixture, while flexible fibres may be used in large sections, such as floor slabs, to control crack width and to improve the handling ability of precast sections. For many reasons, including durability concerns, environmental impact, thermal performance, etc, alternatives to the currently available fibres are being sought. This study examines the potential of using basalt fibres, a mineral and natural material, as reinforcement of concrete sections in comparison to steel fibres and plain concrete mix. Mixes were tested containing 0.5% and 1.0% of basalt fibres measuring 25mm length, 0.5% of the same material with 48mm length and steel fibres measuring 50mm by 0.05%, 0.1%, 0.15% and 0.2% of the concrete volume. For the mechanical performance analysis, the 3-point bending test was led and the fracture energy, Young’s modulus and tensile strength in different moments of the tests were calculated. When compared to the control mixtures and the steel-fibre-reinforced concrete, the mixes containing basalt had a reduction in their elastic modulus, representing a decrease in the concrete brittleness. At the same time, the fracture energy of the mixtures was significantly increased with the basalt fibres in both lengths. Finally, the flexural strength was also higher for the natural fibre reinforced concrete than for the plain concrete and comparable to the results obtained with the addition of steel fibres by 0.15%.

Bond Behaviour of Frp Reinforcing Bars in High-Strength Steel Fibre-Reinforced Concrete

2007 ◽  
Vol 15 (7) ◽  
pp. 569-578 ◽  
Author(s):  
Jong-Pil Won ◽  
Chan-Gi Park ◽  
Hwang-Hee Kim ◽  
Sang-Woo Lee ◽  
Cheol Won
Keyword(s):  
Reinforced Concrete ◽  
High Strength Steel ◽  
High Strength Concrete ◽  
Steel Fibre ◽  
High Strength ◽  
Fibre Reinforced Concrete ◽  
Reinforcing Bars ◽  
Bond Behaviour ◽  
Steel Fibre Reinforced Concrete ◽  
Pullout Load

Current design trends for structures require the increased use of high-strength concrete, which has a compressive strength of over 80 MPa. Its enhanced strength, however, leads to brittle failure problems, which have been resolved by adding steel fibres. Fibre-reinforced polymer (FRP) is actively being studied to resolve the corrosion problems encountered with steel reinforcing bars in concrete structures exposed to adverse environmental conditions. In this study, we experimentally evaluated the bond behaviour of FRP reinforcing bars in high-strength steel fibre-reinforced concrete. A high-strength concrete mix was created with a target strength of over 80 MPa, and steel fibre was added. The FRP reinforcing bars had an increased pullout load with a slow gradient, and the slope of the pullout load reduction curve remained small after the maximum pullout load was reached. In addition, the bond strength increased as steel fibre was added to the FRP reinforcing bar.

Experimental Study of Steel Fibre Bridging Action on Crack Propagation in Fibre Reinforced Concrete

2006 ◽  
Vol 324-325 ◽  
pp. 1067-1070 ◽  
Author(s):  
Zhi Hong Xu ◽  
Wen Yin Liang ◽  
Yu Jing Liang
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
Steel Fibre ◽  
Fibre Reinforced Concrete ◽  
Interfacial Bond ◽  
Cycle Number ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete ◽  
Fibre Bridging ◽  
The Matrix

In this paper the bridging action of steel fibres on the model I crack propagation has been studied experimentally for steel fibre reinforced concrete (FRC). From the experimental results three main conclusions are obtained. First, the bridging action increases with the number of the steel fibres across the crack surface and the stress intensity factor near the crack tip decreases thereby. Second, bridging action increases with the strength of the matrix because the matrix with higher strength can provide stronger interfacial bond with steel fibres. Third, the interfacial bonding gets damaged when the steel fibres under cyclic loads and the bridging action degrades with the cycle number.

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