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

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.

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

Materials ◽

10.3390/ma12223656 ◽

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.

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

10.20944/preprints202111.0566.v1 ◽

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.

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

10.20944/preprints201812.0065.v1 ◽

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.

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

Materials ◽

10.3390/ma12020220 ◽

2019 ◽

Vol 12 (2) ◽

pp. 220 ◽

Cited By ~ 7

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.

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Crack Propagation Analysis of Synthetic vs. Steel vs. Hybrid Fibre-Reinforced Concrete Beams Using Digital Image Correlation Technique

International Journal of Concrete Structures and Materials ◽

10.1186/s40069-020-00427-8 ◽

2020 ◽

Vol 14 (1) ◽

Author(s):

Aniket B. Bhosale ◽

S. Suriya Prakash

Keyword(s):

Reinforced Concrete ◽

Digital Image Correlation ◽

Digital Image ◽

Fracture Behaviour ◽

Process Zone ◽

Reinforced Concrete Beams ◽

Image Correlation ◽

Correlation Technique ◽

Fibre Reinforced Concrete ◽

Hybrid Fibre

Abstract Improvement in fracture behaviour of fibre-reinforced concrete (FRC) due to the inclusion of various types and combinations of fibres is widely reported. The fracture behaviour of FRC needs to be fully understood for the optimum use of these fibres in structural elements. Fracture behaviours of synthetic fibre-reinforced concrete (SynFRC), hybrid fibre-reinforced concrete (HFRC) and steel fibre-reinforced concrete (SFRC) are investigated in this study using digital image correlation (DIC) technique. This work focuses on improvement in the structural performance of FRC through a comprehensive study of the change in the crack length, crack opening and fracture process zone (FPZ) due to different fibres addition and their combinations. Three distinct fibre dosages of 0.50%, 0.75%, and 1.00%, of macro-polyolefin fibres, hooked end steel fibres and their hybrid combination are regarded as research parameters. Test outcomes indicate that HFRC offers higher post-cracking resistance when compared to SynFRC. SFRC showcases superior fracture performance than that of HFRC and SynFRC. Full-field strain measurements from DIC are used to measure the crack openings at different load levels during the fracture tests. Results of DIC analysis show good agreement with experimental measurements. Continuous monitoring of strain contours using DIC reveals the effective engagement of fibres along the depth at higher dosages for HFRC when compared to that of SynFRC. Also, HFRC had longer cracks than SFRC at a particular load.

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