Effect of Fibre Reinforcement on Creep in Early Age Concrete

Laura González,Carlos Thomas,Jokin Rico,Álvaro Gaute

doi:10.3390/app12010257

Laura González, Carlos Thomas + Show 2 more

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https://doi.org/10.3390/app12010257

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Abstract

This research analyses the strain behaviour of fibre-reinforced concrete (FRC) in the event of a creep episode. The analysis of creep experienced by FRC specimens during the test reflects better performance than that predicted by the EHE-08 standard. The authors propose a formulation for the evaluation of creep strain undergone by FRC. During the research, the evolution of the modulus of elasticity of FRC after a creep episode is analysed. After the test campaign, it can be concluded that FRC loaded at an earlier age stiffens after a creep episode. After the creep test is completed, the delayed elastic strain undergone by FRC is analysed and it is observed that FRC loaded at an earlier age undergoes less deformation. The authors propose a formulation for the evaluation of the delayed elastic strain undergone by FRC after a creep episode.

Highlights

Fibre-reinforced concrete (FRC) is being used more and more in structural applications due to the benefits it provides [1]
From the analysis of the creep strain undergone by the FRC specimens analysed during the test, two stages can be distinguished: (a) in a first stage, the creep deformation of the specimens loaded at an earlier age shows a greater strain; (b) in the second stage, the creep strain is equalized for the different loading ages
The strain undergone by FRC specimens loaded at an earlier age, 24 h after their manufacture, shows a much lower level than predicted by the formulation proposed by the EHE-08 standard

Summary

Introduction

Fibre-reinforced concrete (FRC) is being used more and more in structural applications due to the benefits it provides [1]. The addition of fibres to concrete improves the endurance limit, flexural strength, Young’s modulus, and the compressive strength. These improvements depend on the characteristics of the fibres, their material, and their dimensions. The study of creep undergone by structural concretes has a great influence on the design of large structures, as well as on the definition of their construction process. Creep undergone by concrete at early ages influences the design of evolutionary construction processes, such as the construction of bridge decks using the successive cantilever technique [8], while the study of creep at infinite time influences the analysis of the countershafts used in the construction of boards with large spans [9,10,11]

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