Flexural fatigue strength and failure probability of Self Compacting Fibre Reinforced Concrete beams

The paper presents an experimental investigation on the flexural fatigue strength of Self Compacting Fibre Reinforced Concrete (SCFRC) beams. The fatigue life data of SCFRC containing 0.5%, 1.0% and 1.5% by volume of steel fibres have been obtained by conducting flexural fatigue tests on approximately 188 beam specimens of size 100 × 100 × 500 mm under third point loading at different stress levels, ranging from 0.90 to 0.70. Approximately 144 complimentary static flexural tests were also carried out to facilitate fatigue testing. All the static flexural and flexural fatigue tests were conducted on a 100 kN closed loop servo-controlled actuator. The results have been represented in the form of S–N diagrams and to predict the flexural fatigue strength of SCFRC, material coefficients of the fatigue equations have been estimated. Subsequently, family of S–N–Pf curves has been generated from the fatigue test data to graphically represent the relationship between stress level S, fatigue life N, and probability of failure Pf, thus incorporating probability of failure into the fatigue life data of SCFRC. The experimental coefficients of the fatigue equation have also been obtained from the fatigue test data to represent the S–N–Pf curves analytically. The two-million cycles fatigue strength of SCFRC has been found to be higher than that of Normally Vibrated Fibre Reinforced Concrete (NVFRC).

► Proposed equations can be used to predict the flexural fatigue strength of SCFRC.
► Families of S–N–Pf curves developed graphically using fatigue data of SCFRC.
► Analytical relations developed to represent families of S–N–Pf curves of SCFRC.
► SCFRC can sustain higher stress levels when subjected to flexural fatigue loads.