Significance of fiber characteristics on the mechanical properties of steel fiber-reinforced high-strength concrete at different water-cement ratios

Abstract

The incorporation of fiber reinforcement into concrete is not a new approach to improving its ductility. In the past, research has generally focused on specific parameters, such as fiber type, dosage, slenderness, and the inherent strength of concrete. This study addresses the significant gap highlighted by ACI 544.1R by providing a deeper understanding of steel fiber-reinforced concrete (SFRC). The significance of the study is highlighted by the fact that it fills a crucial gap in research, especially considering the inaccuracy of current models related to flexural strength. The study examines in detail the influence of fiber dosage and length on the mechanical properties of SFRC using hooked-end fibers that range in length from 40 to 60 mm and diameters between 0.62 and 0.75 mm, as well as particular water-cement ratios (0.25, 0.35, and 0.45). The study also thoroughly evaluates the precision of widely accepted equations for predicting SFRC's compressive and flexural strengths. Results show that 0.5 to 1.5 % fibers increase concrete's compressive strength, inherent tensile strength, and peak flexural load capacity by 7–27 %, 11–47 %, and 3–124 %, respectively. However, it should be noted that despite the benefits of extending fiber lengths and increasing fiber content, the opposite has little effect on the flexural strength of SFRC. An original equation, which surpasses the existing models, is presented in this study to calculate the modulus of rupture in SFRC. Compared to independent datasets, this model proves remarkably accurate, boasting a predicted-to-tested ratio of 1.01, emphasizing its potential to advance SFRC research.