A Comparative Experimental Study on the Flexural Behavior of High-Strength Fiber-Reinforced Concrete and High-Strength Concrete Beams

In-Hwan Yang,Changbin Joh,Kyoung-Chul Kim

doi:10.1155/2018/7390798

Abstract

The flexural responses of high-strength fiber-reinforced concrete (HSFRC) beams and high-strength concrete (HSC) beams are compared in this study. A series of HSFRC and HSC beams were tested under pure flexural loading. The effects of the type of concrete, compressive strength of the concrete, and tensile rebar ratio on the flexural behavior of the concrete beams were investigated. The flexural behavior of the HSFRC and HSC beams including the induced crack and failure patterns, load and deflection capacity, crack stiffness, ductility index, and flexural toughness was compared. The crack stiffness of the HSC and HSFRC beams increased with the rebar ratio. For the same rebar ratios, the crack stiffness of the HSFRC beams was much greater than that of the HSC beams. The ductility index of the HSC beams decreased sharply with an increase in the rebar ratio, but the ductility index of the HSFRC beams did not show a clear decrease with increasing rebar ratio. The flexural toughness of the HSFRC beams was greater than that of the HSC beams at higher rebar ratios of 1.47% and 1.97%, indicating that the energy absorption of the HSFRC beams was greater than that of the HSC beams. Test results also indicated that HSFRC developed better and more consistent ductility with higher rebar ratio. In addition, the tested bending strength and sectional analysis results were compared.

Highlights

Compared to conventional concrete, high-strength concrete (HSC) develops higher compressive strength along with improved durability, ductility, and high elastic modulus that have recently promoted its extended application to many structures [1,2,3]
Many tests have been performed to evaluate the flexural behavior of HSC beam specimens [6,7,8,9]. e results of Ashour [8] showed that the flexural rigidity increased with greater compressive strength of the concrete. e test results of Mohammadhassani et al [10] showed that an increase in tensile rebar ratio improved the ultimate load capacity but decreased the deflection ductility index. e ductility index is significantly influenced by the rebar ratio
The cracks propagated more deeply into the compressive zone in the HSC beam than in the High-strength fiber-reinforced concrete (HSFRC) beam. is result shows that the steel fibers in the HSFRC beams arrested the crack propagation

Summary

Introduction

High-strength concrete (HSC) develops higher compressive strength along with improved durability, ductility, and high elastic modulus that have recently promoted its extended application to many structures [1,2,3]. E test results of Mohammadhassani et al [10] showed that an increase in tensile rebar ratio improved the ultimate load capacity but decreased the deflection ductility index. E addition of steel fibers can increase the ductility, fracture toughness, and loading capacity of concrete members [11, 12]. Ey concluded that the addition of steel fibers significantly improved the flexural performance, including the bending strength and deflection capacity. Ere are few direct comparison studies on experimental results of HSFRC beams and HSC beams, which have almost the same concrete compressive strength. Erefore, this study intends to compare the characteristics of the flexural behavior of HSC and HSFRC beams that have nearly identical concrete compressive strengths. A comparison of the sectional analysis and experimental results of the bending strength is performed

Experimental Program

Experimental Results

Sectional Analysis of the Bending

Conclusions