scholarly journals Torsional Behavior of High Strength Concrete Members Strengthened by Mixed Steel Fibers

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Mazin Abdul Imam Ahmed ◽  
Jawad Kadhim Mures ◽  
Aqeel Hatem Chkheiwer
Keyword(s):  
Cross Section ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Fibers ◽  
Strength Concrete ◽  
Concrete Members ◽  
Cross Section Area ◽  
Torsional Behavior ◽  
Shape And Size

Twelve mixing steel fibers-reinforced high strength concrete beams were experimentally tested under pure torsion to investigating the concrete member torsional behavior. The first cracking torque, ultimate torsional resistance, crack patterns, effect of steel fiber ratio, effects of shape and size of hollow cross-section, and effect of stirrups reinforcement were discussed. The ratio of mixing steel fiber, different shape and size of hollow cross-section, and ratio of stirrups reinforcement were considers as major parameters. The results are shown that the width of cracks decreases and the cracks number increases with mixing steel fibers ratio increased. The first cracking torque and ultimate torsion load increased with decrease in the hollow cross-section area of high strength concrete members strengthened by steel fibers.

Compressive Strength and Splitting Tensile Strength of Steel Fiber Reinforced Ultra High Strength Concrete (SFRC)

2010 ◽  
Vol 34-35 ◽  
pp. 1441-1444 ◽  
Author(s):  
Ju Zhang ◽  
Chang Wang Yan ◽  
Jin Qing Jia
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Splitting Tensile Strength ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Strength Concrete

This paper investigates the compressive strength and splitting tensile strength of ultra high strength concrete containing steel fiber. The steel fibers were added at the volume fractions of 0%, 0.5%, 0.75%, 1.0% and 1.5%. The compressive strength of the steel fiber reinforced ultra high strength concrete (SFRC) reached a maximum at 0.75% volume fraction, being a 15.5% improvement over the UHSC. The splitting tensile strength of the SFRC improved with increasing the volume fraction, achieving 91.9% improvements at 1.5% volume fraction. Strength models were established to predict the compressive and splitting tensile strengths of the SFRC. The models give predictions matching the measurements. Conclusions can be drawn that the marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) can be overcome by the addition of steel fibers.

scholarly journals Vitality of Steel and Polypropylene Fibers in High Strength Concrete

2019 ◽  
Vol 8 (12) ◽  
pp. 4673-4676
Keyword(s):  
Thermal Insulation ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Gradual Increase ◽  
High Strength ◽  
Fiber Content ◽  
Steel Fibers ◽  
Polypropylene Fibers ◽  
Strength Concrete ◽  
Concrete Mix

The main aim of this work was to investigate the influence of widely used steel fibers and polypropylene fibers on the concrete. From many studies it has been shown that, addition of fibers to the concrete has influenced the cracking of concrete, due to shrinkage, thermal insulation and bleeding of water. So, in this study we made use of ultra high strength concrete mix of M50, and we made use of both steel as well as polypropylene fibers to enhance the properties of the concrete. In this study total five concrete mixes were made with steel fiber in dosages of 2.5%, 2%, 1.5%, 1% and polypropylene fibers are in dosage 0%, 0.5%, 1%, 1.5% of the weight of concrete mix. The specimens were casted and all the specimens are tested for 7days and 28 days strength. The results have depicted a gradual increase in the strength of the concrete as the fiber content increased

scholarly journals PERFORMANCE OF HIGH STRENGTH CONCRETE COLUMNS REINFORCED WITH HYBRID STEEL FIBER UNDER DIFFERENT LOADING CONDITIONS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Emdad K.Z. Balanji ◽  
M. Neaz Sheikh ◽  
Muhammad N.S. Hadi
Keyword(s):  
High Strength Concrete ◽  
Steel Fiber ◽  
Reference Group ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Fibers ◽  
Loading Conditions ◽  
Strength Concrete ◽  
High Strength Concrete Columns ◽  
Strength And Ductility

The strength and ductility of high strength concrete columns improve with the addition of steel fiber. This paper reports the behavior of circular High Strength Concrete (HSC) columns reinforced with Hybrid Steel Fibers (HSF) under different loading conditions. In this study, HSF consisted of a combination of macro steel fibers and micro steel fibers. A total of eight circular specimens of 205 mm diameter and 800 mm height were cast and tested. All specimens were reinforced with same amount of steel reinforcements. The specimens were divided into two groups of four specimens. Group RC (reference group) contained no steel fibers. Group HSF (hybrid steel fibers) contained 2.5% by volume of HSF. From each group one specimen was tested under concentric loading, one under 25 mm eccentric loading, one under 50 mm eccentric loading, and one under four-point loading. The results showed that the specimens reinforced with HSF achieved higher strength and ductility compared to RC specimens under different loading conditions. It was also observed that the presence of HSF delayed the spalling of the concrete cover.

scholarly journals Experimental study on spalling risk of concrete with 115~120MPa subject to ISO834 Fire

2018 ◽  
Author(s):  
Yong Du ◽  
Yu Zhu ◽  
Richard Liew
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Fibers ◽  
Vapor Compression ◽  
Mixture Ratio ◽  
Strength Concrete ◽  
High Rise ◽  
Binder Ratio

High strength concrete encased columns are being developed for erecting high-rise buildings as their higher load bearing capacity and smaller cross section size than normal concrete encased column. At ambient temperature, high strength concrete is always mixed with steel fibers to improve its ductility to match the material properties of high strength steel while constructing concrete encased columns. However, for high strength concrete at elevated temperature, spalling usually can be observed due to different thermal properties of various materials mixed such as siliceous aggregate, cement, silica fume, grit and moisture. Most of previous studies present that pore vapor compression induces high strength concrete spalling and propylene fiber can prevent it from spalling. The aim of the present experimental study is to discover the minimum propylene fiber ratio to prevent spalling of 115~120MPa concrete with aggregate and steel fiber. The experimental study carried out on 17 specimens with different water-binder ratio, steel fiber ratio and monofilament propylene fiber ratio exposed to ISO834 fire. The test results that 0.15% by volume of propylene fibers can prevent 115/120MPa high strength concrete with aggregate from spalling. It is worth noting that propylene fiber mixture ratio of 0.15% is lower than that of EN 1992-1-2 proposed up to 0.22%. Lower propylene fiber mixture ratio has been soak to improve the workability of 115~120MPa high strength concrete with steel fibers.

scholarly journals Research on the Fracture Behavior of Steel-Fiber-Reinforced High-Strength Concrete

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 135
Author(s):  
Shanming Qin ◽  
Danying Gao ◽  
Zhanqiao Wang ◽  
Haitang Zhu
Keyword(s):  
High Strength Concrete ◽  
Fracture Behavior ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Strength Concrete ◽  
Fracture Parameters

The behavior of steel fiber concrete, which is the most widely used building material, has been widely examined. However, methods for calculating Fracture parameters differ by fracture behavior of SFHSC with different strengths. In this study, the fracture behavior of steel-fiber-reinforced high-strength concrete (SFHSC) was -investigated using three-point bending tests. A total of 144 notched concrete beams with a size of 100 mm × 100 mm × 515 mm were tested for three-point bending in 26 groups. The effects of the steel fiber volume ratio, steel fiber type, and relative notch depth on the fracture toughness (KIC) and fracture energy (GF) of SFHSC specimens were studied. The results show that an increase in the volume fraction of steel fiber (ρf) added to high-strength concrete (HSC) significantly improves the fracture behavior of HSC. As compared to milled and sheared corrugated steel fibers, cut bow steel fibers significantly improve the fracture behavior of SFHSC. The effect of incision depth changes on the KIC and GF of SFHSC and HSC for the comparison group has no common characteristics. With an increase in incision depth, the values of KIC of the SFHSC specimens decrease slightly. The GF0.5/GF0.4 of the SFHSC specimens show a decreasing trend with an increase in ρf. According to the test results, we propose calculation models for the fracture behavior of SFHSC with different strengths. Thus, we present a convenient and accurate method to calculate fracture parameters, which lays a foundation for subsequent research.

Effects of Three Steel Fibers on the Properties of High Strength Concrete

2013 ◽  
Vol 753-755 ◽  
pp. 576-580 ◽  
Author(s):  
Hui Lian ◽  
Yun Fei Zhang ◽  
Jiang Tao Xin ◽  
Jian Hua Yang ◽  
Guo Xin Li
Keyword(s):  
High Strength Concrete ◽  
Bending Strength ◽  
Steel Fiber ◽  
Steel Wire ◽  
High Strength ◽  
Diameter Ratio ◽  
Steel Fibers ◽  
Strength Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio

Portland cement, crushed stone, sand and superplasticizer were used to obtain a high strength concrete with a low water to binder ratio. Three steel fibers such as waste steel wire, corrugated steel fiber and arch steel fiber were added into the high strength concrete. The effects of the three fibers on the slump and the strengths such as compressive strength, tensile strength and bending strength were researched. The reduction of the slump and the increasing of the strength of the concrete with the arch steel fiber were the most significant due to the highest length-diameter ratio.

scholarly journals Compressive Behavior and Mechanical Characteristics and Their Application to Stress-Strain Relationship of Steel Fiber-Reinforced Reactive Powder Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Baek-Il Bae ◽  
Hyun-Ki Choi ◽  
Bong-Seop Lee ◽  
Chang-Hoon Bang
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Fibers ◽  
Reactive Powder Concrete ◽  
Test Results ◽  
Strength Concrete ◽  
Estimation Equations ◽  
Reactive Powder

Although mechanical properties of concrete under uniaxial compression are important to design concrete structure, current design codes or other empirical equations have clear limitation on the prediction of mechanical properties. Various types of fiber-reinforced reactive powder concrete matrix were tested for making more usable and accurate estimation equations for mechanical properties for ultra high strength concrete. Investigated matrix has compressive strength ranged from 30 MPa to 200 MPa. Ultra high strength concrete was made by means of reactive powder concrete. Preventing brittle failure of this type of matrix, steel fibers were used. The volume fraction of steel fiber ranged from 0 to 2%. From the test results, steel fibers significantly increase the ductility, strength and stiffness of ultra high strength matrix. They are quantified with previously conducted researches about material properties of concrete under uniaxial loading. Applicability of estimation equations for mechanical properties of concrete was evaluated with test results of this study. From the evaluation, regression analysis was carried out, and new estimation equations were proposed. And these proposed equations were applied into stress-strain relation which was developed by previous research. Ascending part, which was affected by proposed equations of this study directly, well fitted into experimental results.

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