scholarly journals Steel Fiber Enhancement upon Punching Shear Strength of Concrete Flat Plates Exposed to Fire Flame

2021 ◽  
Vol 7 (10) ◽  
pp. 1667-1678
Author(s):  
Ahmed Naji Dalaf ◽  
Shatha Dheyaa Mohammed
Keyword(s):  
Shear Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Punching Shear ◽  
Flat Plates ◽  
Fiber Volume ◽  
Steady State Temperature ◽  
Fire Effect ◽  
Fire Flame

In this study, the effect of fire flame on the punching shear strength of steel fiber reinforced concrete flat plates was experimentally investigated using nine half-scale specimens with dimensions of 1500×1500 mm and a total thickness of 100 mm. The main investigated variables comprised the steel fiber volume fraction 0, 1, and 1.5% and the burning steady state temperature 500 and 600 °C. The specimens were divided into three groups, each group consists of three specimens. The specimens in the first group were tested with no fire effect to be the reference specimens, while the others of the second and third groups were tested after being exposed to fire-flame effect. The adopted characteristics of the fire test were; (one hour) burning time duration and 500 and 600 °C steady state temperature with sudden cooling process (water sprinkling directly after burning). The test results proved that exposing to direct fire effect for one hour caused a reduction in the punching shear strength with an increase in the ultimate mid-span deflection. Also, it was noticed that using steel fiber in the concrete mix leads to a significant increase in the punching shear strength for both the unburned and burned specimens. The ultimate punching load increased by about 11 and 16.6% for the unburned specimens with 1.0 and 1.5% steel fiber volume fraction, respectively, and by about 22.4 and 19% for the burned specimens at 500 °C with 1.0 and 1.5% steel fiber volume fraction, respectively. While, it was increased by about 29.2 and 21.5% for the burned specimens at 600 °C with 1.0 and 1.5% steel fiber volume fraction, respectively, as compared with the reference specimen of each group. Doi: 10.28991/cej-2021-03091751 Full Text: PDF

scholarly journals Evaluation of the Ultimate Strength of the Ultra-High-Performance Fiber-Reinforced Concrete Beams

2021 ◽  
Vol 11 (7) ◽  
pp. 2951
Author(s):  
Baek-Il Bae ◽  
Moon-Sung Lee ◽  
Chang-Sik Choi ◽  
Hyung-Suk Jung ◽  
Hyun-Ki Choi
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Ultimate Strength ◽  
High Performance ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
High Performance Fiber

Evaluation of the ultimate strength for the UHPFRC (ultra-high-performance fiber-reinforced concrete) flexural members was conducted. In this study, an experimental program about UHPFRC beams was conducted with the effect of fiber volume fraction, shear span to depth ratio, and compressive strength of matrix as the main variables. Among them, it was found that fiber volume fraction was the variable that had the greatest influence on the ultimate strength. The inclusion of 2% volume fraction steel fiber increases the shear and flexural strength of UHPFRC beams significantly. In particular, steel fiber inclusion changed the mode of failure of beams from diagonal shear failure into flexural failure. For the classification of failure patterns, the ultimate flexural strength and shear strength of UHPFRC members were evaluated using the current design code and UHPC guidelines. Flexural ultimate strength was affected by the size and shape of the stress block and consideration of the matrix’s tensile strength. For the accurate shear strength prediction of UHPFRC beams, the tensile strength of the high strength matrix and the effect of steel fiber should be considered.

scholarly journals Experimental Study on Shear Performance of Cast-In-Place Ultra-High Performance Concrete Structures

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3254 ◽  
Author(s):  
Li ◽  
Feng ◽  
Ke ◽  
Pan ◽  
Nie
Keyword(s):  
Shear Strength ◽  
High Performance ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Steel Fibers ◽  
Direct Shear ◽  
Ultra High Performance Concrete ◽  
Fiber Volume

In order to study the direct shear properties of ultra-high performance concrete (UHPC) structures, 15 Z-shaped monolithic placement specimens (MPSs) and 12 Z-shaped waterjet treated specimens (WJTSs) were tested to study the shear behavior and failure modes. The effects of steel fiber shape, steel fiber volume fraction and interface treatment on the direct shear properties of UHPC were investigated. The test results demonstrate that the MPSs were reinforced with steel fibers and underwent ductile failure. The ultimate load of the MPS is about 166.9% of the initial cracking load. However, the WJTSs failed in a typical brittle mode. Increasing the fiber volume fraction significantly improves the shear strength, which can reach 24.72 MPa. The steel fiber type has little effect on the shear strength and ductility, while increasing the length of steel fibers improves its ductility and slightly reduces the shear strength. The direct shear strength of the WJTSs made from 16 mm hooked-type steel fibers can reach 9.15 MPa, which is 2.47 times the direct shear strength of the specimens without fibers. Finally, an interaction formula for the shear and compressive strength was proposed on the basis of the experimental results, to predict the shear load-carrying capacity of the cast-in-place UHPC structures.

Shear strength of reinforced concrete beams with a fiber concrete matrix

2006 ◽  
Vol 33 (6) ◽  
pp. 726-734 ◽  
Author(s):  
Fariborz Majdzadeh ◽  
Sayed Mohamad Soleimani ◽  
Nemkumar Banthia
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Reinforcement ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Fiber Volume

The purpose of this study was to investigate the influence of fiber reinforcement on the shear capacity of reinforced concrete (RC) beams. Both steel and synthetic fibers at variable volume fractions were investigated. Two series of tests were performed: structural tests, where RC beams were tested to failure under an applied four-point load; and materials tests, where companion fiber-reinforced concrete (FRC) prisms were tested under direct shear to obtain material properties such as shear strength and shear toughness. FRC test results indicated an almost linear increase in the shear strength of concrete with an increase in the fiber volume fraction. Fiber reinforcement enhanced the shear load capacity and shear deformation capacity of RC beams, but 1% fiber volume fraction was seen as optimal; no benefits were noted when the fiber volume fraction was increased beyond 1%. Finally, an equation is proposed to predict the shear capacity of RC beams.Key words: shear strength, fiber-reinforced concrete, RC beam, stirrups, energy absorption capacity, steel fiber, synthetic fiber.

J Integral of Steel Fiber Reinforced High Strength Concrete

2012 ◽  
Vol 476-478 ◽  
pp. 1568-1571
Author(s):  
Ting Yi Zhang ◽  
Guang He Zheng ◽  
Ping Wang ◽  
Kai Zhang ◽  
Huai Sen Cai
Keyword(s):  
High Strength Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Three Point Bending ◽  
Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.

scholarly journals Influence of MgO and Hybrid Fiber on the Bonding Strength between Reactive Powder Concrete and Old Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mo Jinchuan ◽  
Ou Zhongwen ◽  
Wang Yahui
Keyword(s):  
Tensile Strength ◽  
Bonding Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Drying Shrinkage ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Reactive Powder

The reactive powder concrete (RPC) was used as concrete repair material in this paper. The influence of steel fiber, steel fiber + MgO, and steel fiber + MgO + polypropylene fiber (PPF) on the mechanical properties of RPC repair materials and the splitting tensile strength between RPC and old concrete was studied. Influences of steel fiber, MgO, and PPF on the splitting tensile strength were further examined by using scanning electronic microscopy (SEM) and drying shrinkage test. Results indicated that the compressive and flexural strength was improved with the increasing of steel fiber volume fraction. However, the bonding strength showed a trend from rise to decline with the increasing of steel fiber volume fraction. Although MgO caused mechanical performance degradation of RPC, it improved bonding strength between RPC and existing concrete. The influence of PPF on the mechanical properties of RPC was not obvious, whereas it further improved bonding strength by significantly reducing the early age shrinkage of RPC. Finally, the relationship of drying shrinkage and splitting tensile strength was studied, and the equation between the splitting tensile strength relative index and logarithm of drying shrinkage was obtained by function fitting.

Influence of Fiber Volume Fraction and Aggregate Size on Flexural Behavior of High Strength Steel Fiber-Reinforced Concrete (SFRC)

2013 ◽  
Vol 372 ◽  
pp. 223-226 ◽  
Author(s):  
Seok Joon Jang ◽  
Yeon Jun Yun ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Aggregate Size ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Flexural Behavior ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume

The effects of aggregate size and fiber volume fraction on the flexural behavior of 70MPa high strength steel fiber-reinforced concrete (SFRC) were investigated in this work. Test variables consist of fiber volume fraction (0, 1 and 2 %) and maximum aggregate size (8, 13 and 20 mm). The prism for flexural test was 100 x 100 x 400 mm and was tested under four points loading. Flexural toughness index was measured using ASTM C 1018 procedure. Test results indicated that the addition of steel fiber to 70MPa high strength concrete improves flexural and post-cracking behaviors. This phenomenon is remarkable for SFRC mixture with higher fiber content and smaller aggregate size. Also, the flexural toughness of high strength SFRC depends primarily on fiber content. The maximum aggregate sizes were secondary in importance.

Mechanical Property of Hybrid Steel Fiber Reinforced Cement-Based Composites

2013 ◽  
Vol 539 ◽  
pp. 99-102
Author(s):  
Hai Tao Tan ◽  
Wu Yao ◽  
Xiao Ming Song ◽  
Shuai Dong
Keyword(s):  
Mechanical Property ◽  
Fracture Energy ◽  
Fiber Volume Fraction ◽  
Ultimate Load ◽  
Bending Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Reinforced Cement

The ultimate load, fracture energy and equivalent bending strength of hybrid steel fiber reinforced mortar were investigated with a constant fiber volume fraction in this paper. The results showed that ultimate load of hybrid steel-fiber reinforced mortar was higher than that of mono-fiber reinforced mortar; fracture energy and equivalent bending strength increased with the volume fraction of steel fiber with end hooks.

Shrinkage Performance of Adherence of New Steel Fiber-Reinforced Concrete to Old Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 3569-3574
Author(s):  
Hong Qiang Cheng ◽  
Dan Ying Gao
Keyword(s):  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Shrinkage Force ◽  
The Difference

Shrinkage experiments were done to determine the influence of the volume fraction of steel fiber-reinforcement on the bonding behavior between new concrete and old concrete. The mechanics of the model of restricted shrinkage upon the adherence of new steel fiber reinforced concrete to old concrete are described. The results demonstrate that the difference of shrinkage between the new and the old concrete can been reduced by adding steel fiber to the new concrete. The decrease of shrinkage difference reduces the shrinkage force at the adhesive interface, which improves the adhesion of new concrete to old concrete and the magnitude of the decrease of shrinkage difference is correlated to the steel fiber volume fraction.

Experimental Study on Flexural Properties of Steel Fiber Combined Aggregate Concrete

2014 ◽  
Vol 1065-1069 ◽  
pp. 1903-1906
Author(s):  
Yan Kun Zhang ◽  
Xiao Long Wu ◽  
Yu Cheng Wang
Keyword(s):  
Flexural Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Orthogonal Experiment ◽  
Fiber Volume ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Flexural Performance

In this paper, the flexural performance of steel fiber combine aggregate concrete under the different factor (water cement ratio, quantity of light aggregate, steel fiber volume fraction, and the types of steel fiber) is studied. And the orthogonal experiment method is adopted. From the experiments, it could be found that the most important factor affecting the flexural strength is the steel fiber volume fraction, and then the types of steel fiber, the water cement ratio, and the quantity of light aggregate in the order. With the increasing of the steel fiber volume fraction, the flexural strength of concrete improves obviously. On the basis of the experiment, the relationship formula of flexural strength and the cube compressive strength is given.

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