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 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 Analysis of the Versatility of Multi-Linear Softening Functions Applied in the Simulation of Fracture Behaviour of Fibre-Reinforced Cementitious Materials

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3656
Author(s):  
Alejandro Enfedaque ◽  
Marcos G. Alberti ◽  
Jaime C. Gálvez
Keyword(s):  
Reinforced Concrete ◽  
Fracture Behaviour ◽  
Constitutive Relations ◽  
Cementitious Materials ◽  
Point Of View ◽  
Cohesive Crack ◽  
Attractive Alternative ◽  
Fibre Reinforced Concrete ◽  
Structural Applications ◽  
Linear Softening

Fibre-reinforced cementitious materials (FRC) have become an attractive alternative for structural applications. Among such FRC, steel- and polyolefin fibre-reinforced concrete and glass fibre-reinforced concrete are the most used ones. However, in order to exploit the properties of such materials, structural designers need constitutive relations that accurately reproduce FRC fracture behaviour. This contribution analyses the suitability of multilinear softening functions combined with a cohesive crack approach for reproducing the fracture behaviour of the FRC mentioned earlier. The performed implementation accurately simulated fracture behaviour, while being versatile, robust, and efficient from a numerical point-of-view.

scholarly journals Analysis of the Versatility of Multi-linear Softening Functions Applied to the Simulation of the Fracture Behaviour of Fibre Reinforced Cementitious Materials

2019 ◽  
Author(s):  
Alejandro Enfedaque ◽  
Marcos G. Alberti ◽  
Jaime C. Galvez
Keyword(s):  
Reinforced Concrete ◽  
Fracture Behaviour ◽  
Constitutive Relations ◽  
Cementitious Materials ◽  
Point Of View ◽  
Cohesive Crack ◽  
Attractive Alternative ◽  
Fibre Reinforced Concrete ◽  
Structural Applications ◽  
Linear Softening

Fibre reinforced cementitious materials (FRC) have become an attractive alternative for structural applications. Among such FRC, steel and polyolefin fibre reinforced concrete and glass fibre reinforced concrete are the most used ones. However, in order to exploit the properties of such materials structural designers need constitutive relations that reproduce FRC fracture behaviour accurately. This contribution analyses the suitability of multilinear softening functions combined with a cohesive crack approach for reproducing the fracture behaviour of the FRC previously mentioned. The implementation performed accurately simulates the fracture behaviour while being versatile, robust and efficient from a numerical point of view.

Components of Fracture Response of Steel Fibre Reinforced Concrete Specimens

2016 ◽  
Vol 827 ◽  
pp. 287-291 ◽  
Author(s):  
Ivana Havlíková ◽  
Petr Frantík ◽  
Pavel Schmid ◽  
Hana Šimonová ◽  
Václav Veselý ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
Plain Concrete ◽  
Fibre Reinforced Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Three Point Bending ◽  
Notched Specimens ◽  
Fracture Tests ◽  
Work Of Fracture

Records of fracture tests on steel fibre reinforced concrete notched specimens in a three-point bending configuration are evaluated in detail and selected results are discussed in the paper. The values of fracture parameters are determined using work of fracture method and double-K fracture model. Primarily, the role of plain concrete as a matrix in steel fibre reinforced concrete specimens is studied with regard to the recorded fracture response.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
AMIR SYAFIQ SAMSUDIN ◽  
MOHD HISBANY MOHD HASHIM ◽  
SITI HAWA HAMZAH ◽  
AFIDAH ABU BAKAR
Keyword(s):  
Reinforced Concrete ◽  
Bending Strength ◽  
Steel Fibre ◽  
Concrete Slab ◽  
Future Application ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Conventional Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Bending Load

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.

scholarly journals Fracture and Size Effect of PFRC Specimens Simulated by Using a Trilinear Softening Diagram: A Predictive Approach

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
A Priori ◽  
Plain Concrete ◽  
Specimen Size ◽  
Bending Test ◽  
Orientation Factor ◽  
Fibre Reinforced Concrete ◽  
Softening Function ◽  
Three Point Bending

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.

scholarly journals Numerical Simulation of the Fracture Behaviour of High-Performance Fibre Reinforced Concrete by Using a Cohesive-Crack-Based Inverse Analysis

2021 ◽  
Author(s):  
Alejandro Enfedaque ◽  
Marcos G. Alberti ◽  
Jaime C. Gálvez ◽  
Pedro Cabanas
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Inverse Analysis ◽  
High Performance ◽  
Fracture Behaviour ◽  
Constitutive Models ◽  
Cohesive Crack ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Structural Applications

Fibre reinforced concrete (FRC) has become an alternative for structural applications due its outstanding mechanical properties. The appearance of new types of fibres and the fibre cocktails that can be configured mixing them has created FRC that clearly exceed the minimum mechanical properties required in the standards. Consequently, in order to take full advantage of the contribution of the fibres in construction projects, it is of great interest to have constitutive models that simulate the behaviour of the materials. This study aimed to simulate the fracture behaviour of five types of FRC, three with steel hooked fibres, one with a combination of two types of steel fibres and one with a combination of polyolefin fibres and two types of steel fibres, by means of an inverse analysis based on the cohesive crack approach. The results of the numerical simulations defined the softening functions of each FRC formulation and have pointed out the synergies that are created through use of fibre cocktails. The information obtained might suppose a remarkable advance for designers using high-performance FRC in structural elements.

scholarly journals Simulation of fracture propagation in fibre-reinforced concrete using FDEM: an application to tunnel linings

2019 ◽  
Vol 7 (5) ◽  
pp. 961-974 ◽  
Author(s):  
A. Farsi ◽  
A. Bedi ◽  
J. P. Latham ◽  
K. Bowers
Keyword(s):  
Reinforced Concrete ◽  
Fracture Propagation ◽  
Fibre Reinforced Concrete ◽  
Finite Element Code ◽  
Bending Tests ◽  
Three Point Bending ◽  
Tunnel Section ◽  
Tunnel Design ◽  
Joint Element ◽  
Design Case

AbstractThe application of the combined finite-discrete element method (FDEM) to simulate fracture propagation in fibre-reinforced-concrete (FRC)-lined tunnels has been investigated. This constitutes the first attempt of using FDEM for the simulation of fracture in FRC structures. The mathematical implementations of the new FDEM joint-element constitutive model are first introduced, and the numerical model is then validated comparing the results for plain and FRC beams with three-point bending experimental data. The code has also been applied to two practical tunnel design case studies, showing different behaviours depending on the type of concrete and shape of tunnel section. The FDEM simulations of the linings are also compared with results from a finite element code that is commonly used in the engineering design practise. These results show the capabilities of FDEM for better understanding of the fracture mechanics and crack propagation in FRC tunnels. A methodology for directly inferring the numerical parameters from three-point bending tests is also illustrated. The results of this research can be applied to any FRC structure.

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