Suárez, F.; Enfedaque, A.; Alberti, M.G.; Gálvez, J.C. Numerical Simulation of PFRC Fracture Subjected to High Temperature by Means of a Trilinear Softening Diagram. Materials2023, 16, 6048.
Suárez, F.; Enfedaque, A.; Alberti, M.G.; Gálvez, J.C. Numerical Simulation of PFRC Fracture Subjected to High Temperature by Means of a Trilinear Softening Diagram. Materials 2023, 16, 6048.
Suárez, F.; Enfedaque, A.; Alberti, M.G.; Gálvez, J.C. Numerical Simulation of PFRC Fracture Subjected to High Temperature by Means of a Trilinear Softening Diagram. Materials2023, 16, 6048.
Suárez, F.; Enfedaque, A.; Alberti, M.G.; Gálvez, J.C. Numerical Simulation of PFRC Fracture Subjected to High Temperature by Means of a Trilinear Softening Diagram. Materials 2023, 16, 6048.
Abstract
Fibre reinforced concrete (FRC) has been used for decades in certain applications of the construction industry, such as tunnel linings and precast elements, but has experienced an important progress in recent times, boosted by the inclusion of guidelines for their use in some national and international standards. Traditional steel fibres have been studied in depth and their performance is well known although in recent years new materials have been proposed as possible alternatives. Polyolefin macro-fibres, for instance, have proven to enhance the mechanical properties of concrete and the parameters that define their behaviour (fibre length, fibre proportion or casting method, for instance) have been identified. These fibres overcome certain traditional problems related to steel fibres, such as corrosion or their interaction with magnetic fields, which can limit the use of steel in some applications. The behaviour of polyolefin fibre reinforce concrete (PFRC) has been numerically reproduced with success through an embedded cohesive crack formulation that uses a trilinear softening diagram to describe the fracture behaviour of the material. Furthermore, concrete behaves well under high temperatures or fire events, especially when it is compared with other construction materials, but the behaviour of PFRC must be analysed if the use of these fibres is to be extended. To this end, the degradation of PFRC fracture properties has been recently experimentally analysed under a temperature range between 20ºC and 200ºC. As temperature increases, polyolefin fibres modify their mechanical properties and their shape, which reduce their performance as reinforcement of concrete. In this work, those experimental results, which include results of low (3 kg/m3) and high (10 kg/m3) proportion PFRC specimens, are used as reference to study the fracture behaviour of PFRC exposed to high temperatures from a numerical point of view. The experimental load-deflection diagrams are reproduced by modifying the trilinear diagram used in the cohesive model, which helps to understand how the trilinear diagram parameters are affected by high temperature exposure. Finally, some expressions are proposed to adapt the initial trilinear diagram (obtained with specimens not exposed to high temperature) in order to numerically reproduce the fracture behaviour of PFRC affected by high temperature exposure.
Keywords
High temperature; Polyolefin fibre reinforced concrete; Trilinear softening function; Cohesive model
Subject
Engineering, Civil Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
