A Study of the Flexural Behavior of Fiber-Reinforced Concretes Exposed to Moderate Temperatures.

Marta Caballero-Jorna,Pedro Serna,Marta Roig-Flores

doi:10.3390/ma14133522

Marta Caballero-Jorna, Pedro Serna + Show 1 more

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https://doi.org/10.3390/ma14133522

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Abstract

The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C.

Highlights

Academic Editors: Branko Šavija, Ivan Ignjatović and Ravi A
The results of the characterization tests are presented
This effect could be explained by the high fiber volume and the aspect ratio of this type of fiber, which affects the number per cubic meter in concrete [10]

Summary

Introduction

Academic Editors: Branko Šavija, Ivan Ignjatović and Ravi A. Fiber-reinforced concrete (FRC) is a composite material containing disperse fibers inside a cementitious matrix. FRC is already used worldwide, and fibers have been gradually included in standards and codes [3,4,5]. These codes are generally based on experiences with steel fibers (the most extended fiber type used in structural applications) and do not cover all types of fiber material on the market. The FIB MC2010 [5] expose warnings for those with a Young’s modulus that is affected by time or thermo-hygrometric phenomena, as synthetic fibers. Synthetic fibers have emerged in different shapes, sizes and compositions and in recent years have gained popularity, especially polypropylene fibers

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