Dispersion, Workability and Mechanical Properties of Different Steel-Microfiber-Reinforced Concretes with Low Fiber Content

Ying Zhou,Yi Xiao,Zheng Lu,Anqi Gu

doi:10.3390/su10072335

Abstract

Steel-microfiber-reinforced concrete has been proven to be an effective type of hybrid fiber-reinforced concrete (HyFRC). The microfiber used in these concretes generally include microfilament steel (MS) fibers and synthetic fibers, such as polypropylene (PP), polyvinyl alcohol (PVA), and polyacrylonitrile (PAN) fibers. This study aims to obtain the optimal type of steel-microfiber HyFRC, with low fiber content, which can be easily used in engineering projects without special fabrication procedures, thus achieving the concept of sustainability. Four types of HyFRC that blend steel (S) fiber with MS, PP, PVA and PAN were studied. These HyFRC were compared through a systematic experimental campaign in which the fiber dispersion, mixture workability, and concrete mechanical properties were investigated. The experimental results of the fiber dispersion and mixture workability indicate the following qualitative relationship: MS > PVA ≈ PP > PAN. For the mechanical properties of the concretes, the S-MS, and S-PVA HyFRCs generate an overall higher enhancing effect than those of the S-PP and S-PAN HyFRCs and show a positive hybridization effect for most properties. The S-MS HyFRC is superior in strength, and the S-PVA HyFRC has a significantly improved toughness. Because PVA has relatively good dispersion and workability properties, and toughness is the most important and effective mechanical property in the fiber-reinforced concrete, this study recommends that the S-PVA HyFRC is the optimal type of steel-microfiber HyFRC.

Highlights

Concrete is the most widely used material in civil engineering and consumes a large amount of energy every year
The mechanical properties of the low-fiber-content Hybrid fiber-reinforced concrete (HyFRC) may be less attractive than HyFRC mixtures with higher fiber contents, the HyFRCs studied in this paper are more economically efficient, consumes less energy, and are much simpler to fabricate in engineering applications, approaching the concept of sustainability
A systematic experimental study on the optimization of the HyFRC type is presented in this study

Summary

Introduction

Concrete is the most widely used material in civil engineering and consumes a large amount of energy every year. The additional special care regarding the fabrication procedures limits the material’s application in engineering To solve this problem, Hossain et al [9] and Jen et al [10] developed an appealing method by adding viscosity modifying admixture (VMA) into the mixture to increase its workability. Hossain et al [9] and Jen et al [10] developed an appealing method by adding viscosity modifying admixture (VMA) into the mixture to increase its workability This would further complicate the fabrication process and increase the material cost. Another method to achieve a balance is to optimize the mechanical properties with an acceptable reduction in workability, leading to a low fiber content. The mechanical properties of the low-fiber-content HyFRCs may be less attractive than HyFRC mixtures with higher fiber contents, the HyFRCs studied in this paper are more economically efficient, consumes less energy, and are much simpler to fabricate in engineering applications, approaching the concept of sustainability

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