Flexural Fatigue Strength of Steel Fibrous Concrete Beams

Abstract

The paper presents results of an investigation conducted to study the fatigue strength of steel fibre reinforced concrete (SFRC) beams in flexure. An experimental programme was planned in which about two hundred and thirty three flexural fatigue tests were conducted at different stress levels and stress ratios to obtain the fatigue lives of SFRC containing different volume fractions of steel fibres. One hundred and sixty six complimentary static flexural tests were also conducted to obtain the static flexural strength of SFRC beams prior to fatigue testing. The specimens of size 100 × 100 × 500 mm were used for static flexural as well as flexural fatigue tests and incorporated 0.5, 1.0 and 1.5% volume fraction of corrugated steel fibres of size 0.6 × 2.0 × 30 mm. The concept of equivalent fatigue life was then applied to the fatigue life data to incorporate the effects of stress level, stress ratio and survival probability into the fatigue equation. The results indicate that the distribution of equivalent fatigue life of SFRC can approximately be described by the two-parameter Weibull distribution. The material coefficients of the fatigue equation have been determined corresponding to different survival probabilities so that the fatigue equation can be used to predict the flexural fatigue strength of SFRC.