Normal‐ and High‐Strength Fiber‐Reinforced Concrete under Compression

TLDR

The complete stress‑strain behavior of steel‑fiber reinforced concrete in compression is required for its use in structural applications. The study presents experimental stress‑strain data for fiber‑reinforced concrete across 5–12 ksi and proposes a simple equation to predict the full stress‑strain curve. The authors tested concrete with three fiber volume fractions (30–60 kg/m³) and three aspect ratios (60–100), measuring peak stress, strain, modulus, toughness, and curve shape, and developed a simple predictive equation. Steel fibers increase concrete toughness, with modest gains in strength, peak strain, and modulus, while higher silica‑fume content makes the mix more brittle; the proposed equation accurately predicts the stress‑strain curve for non‑silica‑fume mixes.

Abstract

TO use steel fiber‐reinforced concrete in structural applications, the complete stress‐strain behavior of the material in compression is needed. This paper presents the experimental stress‐strain behavior of fiber‐reinforced concrete with compressive strength ranging from 5 ksi to 12 ksi (35 MPa to 85 MPa). Three fiber volume fractions of 50 lb/cu yd, 75 lb/cu yd, and 100 lb/cu yd (30kg/m3,45kg/m3, and 60kg/m3) and three aspect ratios of 60, 75, and 100 are investigated. The influence of the fiber‐reinforcing parameters on the peak stress, corresponding strain, the secant modulus of elasticity, the toughness of concrete, and the curve shape are reported. A simple equation is proposed to predict the complete stress‐strain curve. Addition of steel fibers to concrete with or without silica fume effectively increases the toughness of such concrete. A marginal increase in the compressive strength, the strain corresponding to peak stress, and the secant modulus of elasticity is also obtained. The increase of silica‐fume content renders the fiber‐reinforced concrete more brittle then non‐silica‐fume concrete. The equation proposed to generate the complete stress‐strain curve for non‐silica‐fume fiber‐reinforced concrete provides a good correlation between predicted and experimental results.