scholarly journals Influence of Fiber Distribution and Orientation in the Fracture Behavior of Polyolefin Fiber-Reinforced Concrete

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 220 ◽  
Author(s):  
Alejandro Enfedaque ◽  
Marcos Alberti ◽  
Jaime Gálvez
Keyword(s):  
Reinforced Concrete ◽  
Constitutive Relations ◽  
Fiber Reinforced Concrete ◽  
Cohesive Crack ◽  
Homogeneous Distribution ◽  
Attractive Alternative ◽  
Fiber Reinforced ◽  
Self Compacting Concrete ◽  
Conventional Concrete ◽  
Three Point Bending

Polyolefin fiber-reinforced concrete (PFRC) has become an attractive alternative to steel for the reinforcement of concrete elements, mainly due to its chemical stability and the residual strengths that can be reached with lower weights. The use of polyolefin fibers can meet the requirements of standards, although the main constitutive relations are based on experience with steel fibers. Therefore, the structural contributions of the fibers should be assessed by inverse analysis. In this study, the fiber dosage was fixed at 6 kg/m3, and both self-compacting concrete and conventional concrete were used to compare the influence of the positioning of the fibers. An idealized homogeneous distribution of the fibers with such fibers crossing from side to side of the specimen was added to self-compacting concrete. The experimental results of three-point bending tests on notched specimens were reproduced by using the cohesive crack approach. Hence, constitutive relations were found. The significance of this research relies on the verification of the formulations found to build constitutive relations. Moreover, with these results, it is possible to establish a higher threshold for the performance of PFRC and the difficulties of limiting the first unloading branch typical of fracture tests of PFRC.

scholarly journals Influence of the Fibre Distribution and Orientation in the Fracture Behaviour of Polyolefin Fibre Reinforced Concrete

2018 ◽  
Author(s):  
Alejandro Enfedaque ◽  
Marcos G. Alberti ◽  
Jaime C. Gálvez
Keyword(s):  
Reinforced Concrete ◽  
Constitutive Relations ◽  
Cohesive Crack ◽  
Homogeneous Distribution ◽  
Attractive Alternative ◽  
Fibre Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Conventional Concrete ◽  
Three Point Bending ◽  
Fracture Tests

Polyolefin fibre reinforced concrete (PFRC) has become an attractive alternative to steel for the reinforcement of concrete elements mainly due to its chemical stability and the residual strengths that can be reached with lower weights. The use of polyolefin fibres can meet the requirements in the standards, although the main constitutive relations are based on the experience with steel fibres. Therefore, the structural contributions of the fibres should be assessed by inverse analysis. In this study, the fibre dosage has been fixed at 6kg/m³ and both self-compacting concrete and conventional concrete have been used to compare the influence of the positioning of the fibres. An idealized homogeneous distribution of the fibres with such fibres crossing from side to side of the specimen has been added to self-compacting concrete. The experimental results of three-point bending tests on notched specimens have been reproduced by using the cohesive crack approach. Hence, the constitutive relations were found. The significance of this research relies on the verification of the formulations found to build the constitutive relations. Moreover, with these results it is possible to establish the higher threshold of the performance of PFRC and the difficulties of limiting the first unloading branch typical of fracture tests of PFRC.

scholarly journals Stress–Strain Behavior of FRC in Uniaxial Tension Based on Mesoscopic Damage Model

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 689
Author(s):  
Weifeng Bai ◽  
Xiaofeng Lu ◽  
Junfeng Guan ◽  
Shuang Huang ◽  
Chenyang Yuan ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Uniaxial Tension ◽  
Damage Evolution ◽  
Constitutive Relations ◽  
Damage Mechanism ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Strain Behavior ◽  
Nonlinear Stress

Fiber-reinforced concrete (FRC) is widely used in the field of civil engineering. However, the research on the damage mechanism of FRC under uniaxial tension is still insufficient, and most of the constitutive relations are macroscopic phenomenological. The aim is to provide a new method for the investigation of mesoscopic damage mechanism of FRC under uniaxial tension. Based on statistical damage theory, the damage constitutive model for FRC under uniaxial tension is established. Two kinds of mesoscopic damage mechanisms, fracture and yield, are considered, which ultimately determines the macroscopic nonlinear stress–strain behavior of concrete. The yield damage mode reflects the potential bearing capacity of materials and plays a key role in the whole process. Evolutionary factor is introduced to reflect the degree of optimization and adjustment of the stressed skeleton in microstructure. The whole deformation-to-failure is divided into uniform damage phase and local failure phase. It is assumed that the two kinds of damage evolution follow the independent triangular probability distributions, which could be represented by four characteristic parameters. The validity of the proposed model is verified by two sets of test data of steel fiber-reinforced concrete. Through the analysis of the variation law of the above parameters, the influence of fiber content on the initiation and propagation of micro-cracks and the damage evolution of concrete could be evaluated. The relations among physical mechanism, mesoscopic damage mechanism, and macroscopic nonlinear mechanical behavior of FRC are discussed.

Fracture properties of self-compacting fiber-reinforced concrete

2020 ◽  
Vol 11 (4) ◽  
pp. 112
Author(s):  
Mariam Farouk Ghazy ◽  
Metwally Abd Allah Abd Elaty ◽  
Omar Daboun
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Test Results ◽  
Fiber Reinforced ◽  
Bending Tests ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Slump Flow ◽  
Hardened Properties ◽  
Application Fields

Self-compacting concrete (SCC) is an innovative concrete that does not necessitate vibration for placing and compaction. Nineteen concrete mixes were investigated including a control mix without fibers as well as eighteen SCC with fibers (SCFRC) mixes. Three types of fibers (polypropylene, glass and steel) were used. Slump flow, L-box, V-funnel as well as column segregation tests were conducted to assess the fresh properties. Whereas, compressive, splitting tensile and flexural strengths were measured to assess the hardened properties of SCFRC. Three point bending tests were performed for the purpose of assessing the fracture properties of SCFRC. Test results showed that the inclusion of fibers to produce SCFRC mixtures remarkably enhanced the fracture properties including fracture energy (Gf) and fracture toughness (K1c). Inclusion of steel fibers with 2% volume fractions showed an improvement with 26.9 times for Gf over the control mix. Whereas, 104% increase in K1c was recorded for the same mix over the mix without fibers. Adding fibers to SCC to produce self-compacting fiber reinforced concrete (SCFRC) will expand its advantages. However, the application fields still need to understand the properties of SCFRC.

Relationship between Fiber Orientation and Flexural Strength in Ultra-High-Performance Fiber-Reinforced Concrete Panels

2014 ◽  
Vol 629-630 ◽  
pp. 71-78 ◽  
Author(s):  
Bo Zhou ◽  
Yuichi Uchida
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Fiber Orientation ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Concrete Panels ◽  
High Performance Fiber

In this study, the influence of fiber orientation on the flexural strength of ultra-high-performance fiber-reinforced concrete (UHPFRC) was examined. To this end, a circular UHPFRC panel measuring φ1,200 × 50 mm was cast from its center, and test specimens measuring 50 × 50 × 200 mm with 10 mm notches for three-point bending tests were cut from it with angles of 0, 30, 60 and 90° between the specimen axis and the radial direction of the panel. After the bending test, fiber orientation on the ruptured surfaces of the specimens was observed. The flexural strengths of the specimens cut at angles of 60, 30 and 0° were 80, 40 and 10% of that for the specimen cut at an angle of 90°. It was also found that the flexural strength of specimens cut from a rectangular panel cast from its center point depended on their original positions and orientation within the panel. Similar fiber orientation characteristics were found in the circular and rectangular panels.

scholarly journals Behaviour of hybrid fibre reinforced concrete-filled steel tubular beams and columns

2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Kathiresan Karuppanan ◽  
Vennila Govindasamy
Keyword(s):  
Reinforced Concrete ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Fiber Volume ◽  
Polypropylene Fibres ◽  
Conventional Concrete ◽  
Flexural Performance ◽  
Tubular Sections

ABSTRACT This paper presents the flexural performance of newly developed hybrid fiber reinforced concrete-filled steel tubular sections. The test parametres are fiber volume fraction and fiber hybridation ratio. Initially mechanical properties studied for 10 mono fiber reinforced concrete mixes using steel and Polypropylene fibres with 0.5%, 1.0%, 1.5%, 2.0% and 2.5% volume fraction. Based on the performance optimum fiber dosage was determined in each fiber, with the same volume fraction three different fiber hybridation was developed. Developed hybrid fiber reinforcement concrete, conventional concrete and optimum mono fiber reinforced concrete was used in the concrete-filled steel tubular beams and columns to determine the structural performance. The test results shows that, fiber reinforced concrete-filled steel tubular beams display significant improvement in the flexural performance.

scholarly journals Fiberconcrete with Non-Homogeneous Fibers Distribution

2015 ◽  
Vol 2 ◽  
pp. 67
Author(s):  
Vitalijs Lusis ◽  
Andrejs Krasnikovs
Keyword(s):  
Reinforced Concrete ◽  
Crack Opening ◽  
Fiber Reinforced Concrete ◽  
Homogeneous Distribution ◽  
Structural Elements ◽  
Fiber Reinforced ◽  
Vertical Deflection ◽  
Load Bearing ◽  
Four Point Bending ◽  
Different Types

In this research fiber reinforced concrete prisms with layers of non-homogeneous distribution of fibers inside them were elaborated. Fiber reinforced concrete is important material for load bearing structural elements. Traditionally fibers are homogeneously dispersed in a concrete. At the same time in many situations fiber reinforced concrete with homogeneously dispersed fibers is not optimal (majority of added fibers are not participating in load bearing process). It is possible to create constructions with non-homogeneous distribution of fibers in them in different ways. Present research is devoted to one of them. In the present research three different types of layered prisms with the same amount of fibers in them were experimentally produced (of this research prisms of non-homogeneous fiber reinforced concrete with dimensions 100×100×400 mm were designed. and prisms with homogeneously dispersed fibers were produced for reference as well). Prisms were tested under four point bending conditions till crack opening in each prism reached 6 mm.  During the testing vertical deflection at the center of a prism and crack opening were fixed by the linear displacements transducers in real time.

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