scholarly journals Bending Performance of Steel Fiber Reinforced Concrete Beams Based on Composite-Recycled Aggregate and Matched with 500 MPa Rebars

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 930 ◽  
Author(s):  
Xiaoke Li ◽  
Songwei Pei ◽  
Kunpeng Fan ◽  
Haibin Geng ◽  
Fenglan Li
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Aggregate Concrete ◽  
Reinforced Concrete Beams ◽  
Recycled Aggregate ◽  
Fiber Reinforced

To promote the engineering application of recycled aggregate for concrete production with good adaptability and economic efficiency, this paper performed a campaign to investigate the flexural performance of steel fiber reinforced composite-recycled aggregate concrete (SFR-CRAC) beams matched with 500 MPa longitudinal rebars. The composite-recycled aggregate has features of the full use recycled fine aggregate and small particle recycled coarse aggregate, and the continuous grading of coarse aggregate ensured by admixing the large particle natural aggregate about 35% to 45% in mass of total coarse aggregate. The properties of SFR-CRAC have been comprehensively improved by using steel fibers. With a varying volume fraction of steel fiber from 0% to 2.0%, 10 beam specimens were produced. The flexural behaviors of the beams during the complete loading procedure were experimentally studied under a four-point bending test. Of which the concrete strain at mid-span section, the appearance of cracks, the crack distribution and crack width, the mid-span deflection, the tensile strain of longitudinal rebars, and the failure patterns of the beams were measured in detail. Results indicated that the assumption of plane cross-section held true approximately, the 500 MPa longitudinal rebars worked at a high stress level within the limit width of cracks on reinforced SFR-CRAC beams at the normal serviceability, and the typical failure occurred with the yield of 500 MPa longitudinal rebars followed by the crushed SFR-CRAC in compression. The cracking resistance, the flexural capacity, and the flexural ductility of the beams increased with the volume fraction of steel fiber, while the crack width and mid-span deflection obviously decreased. Finally, by linking to those for conventional reinforced concrete beams, formulas are suggested for predicting the cracking moment, crack width, and flexural stiffness at normal serviceability, and the ultimate moment at bearing capacity of reinforced SFR-CRAC beams.

scholarly journals Experimental Study on Shear Behavior of Steel Fiber Reinforced Concrete Beams with High-Strength Reinforcement

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1682 ◽  
Author(s):  
Jun Zhao ◽  
Jingchao Liang ◽  
Liusheng Chu ◽  
Fuqiang Shen
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Steel Fiber ◽  
High Strength ◽  
Shear Behavior ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Diagonal Crack

Many researchers have performed experimental and theoretical studies on the shear behavior of steel fiber reinforced concrete (SFRC) beams with conventional reinforcement; few studies involve the shear behavior of SFRC beams with high-strength reinforcement. In this paper, the shear test of eleven beams with high-strength reinforcement was carried out, including eight SFRC beams and three reinforced concrete (RC) beams. The load-deflection curve, concrete strain, stirrup strain, diagonal crack width, failure mode and shear bearing capacity of the beams were investigated. The test results show that steel fiber increases the stiffness, ultimate load and failure deformation of the beams, but the increase effect of steel fiber decreases with the increase of stirrup ratio. After the diagonal crack appears, steel fiber reduces the concrete strains of the diagonal section, stirrup strains and diagonal crack width. In addition, steel fiber reduces crack height and increases crack number. Finally, the experimental values of the shear capacities were compared with the values calculated by CECS38:2004 and ACI544.4R, and the equation of shear capacity in CECS38:2004 was modified to effectively predict the shear capacities of SFRC beams with high-strength reinforcement.

Study on Retrofitting and Strengthening of Reinforced Concrete Beams Using Fibrous Concrete

2021 ◽  
Vol 9 (8) ◽  
pp. 1676-1684
Author(s):  
Natalia Sharma
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Cement Matrix ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

Abstract: Reinforced concrete structures are frequently in need of repair and strengthening as a result of numerous environmental causes, ageing, or material damage under intense stress conditions, as well as mistakes made during the construction process. RC structures are repaired using a variety of approaches nowadays. The usage of FRC is one of the retrofitting strategies. Steel fiber reinforced concrete (SFRC) was used in this investigation because it contains randomly dispersed short discrete steel fibers that operate as internal reinforcement to improve the cementitious composite's characteristics (concrete). The main rationale for integrating small discrete fibers into a cement matrix is to reduce the amount of cement used. The principal reason for incorporating short discrete fibers into a cement matrix is to reduce cracking in the elastic range, increase the tensile strength and deformation capacity and increase the toughness of the resultant composite. These properties of SFRC primarily depend upon length and volume of Steel fibers used in the concrete mixture. In India, the steel fiber reinforced concrete (SFRC) has seen limited applications in several structures due to the lack of awareness, design guidelines and construction specifications. Therefore, there is a need to develop information on the role of steel fibers in the concrete mixture. The experimental work reported in this study includes the mechanical properties of concrete at different volume fractions of steel fibers. These mechanical properties include compressive strength, split tensile strength and flexural strength and to study the effect of volume fraction and aspect ratio of steel fibers on these mechanical properties. However, main aim of the study was significance of reinforced concrete beams strengthened with fiber reinforced concrete layer and to investigate how these beams deflect under strain. The objective of the investigation was finding that applying FRC to strengthen beams enhanced structural performance in terms of ultimate load carrying capacity, fracture pattern deflection, and mode of failure or not.

scholarly journals Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets

Materials ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. 666 ◽  
Author(s):  
Viktor Gribniak ◽  
Vytautas Tamulenas ◽  
Pui-Lam Ng ◽  
Aleksandr K. Arnautov ◽  
Eugenijus Gudonis ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Mechanical Behavior ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

Research on Influences of the Coarse Aggregate Size on the Cracks of the Reinforced Beam

2012 ◽  
Vol 503-504 ◽  
pp. 832-836
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Reinforced Beams ◽  
Maximum Crack

This paper gives the influences of the coarse aggregate size on the cracks of the beam with different aggregate sizes under static loads. The coarse aggregate sizes are ranked into three classes: small size (4.75mm ~ 19mm), big size (19mm ~ 37.5mm) and mixed size (4.75mm ~ 37.5mm). The developments of cracks of three reinforced concrete beams with the different of coarse aggregate sizes under the static loads are researched. The results show that under the action of the same loads, The reinforced concrete beams with the big aggregate size and mixed aggregate size have almost the same maximum crack width, while the maximum crack width of the beam with small aggregate size is less than formers. Using fractal theory, the fractal dimension of the cracks is studied. The result shows that the aggregate sizes have significant effect to the cracks on the reinforced beams.

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