Experimental Investigations and Numerical Simulations on the Flexural Fatigue Behavior of Plain and Fiber-Reinforced Concrete

Experimental investigations are carried out on plain concrete and fiber-reinforced concrete (FRC) with different volume fractions (0.5, 1, and 2%) of steel fibers to evaluate their fatigue behavior. Three load ranges, namely 20–65%, 20–75%, and 20–85% of ultimate load, are considered for studies under fatigue loading. Unified stress-number of cycles (S-N) expressions are proposed for estimation of flexural fatigue life of plain concrete as well as FRC based on the data obtained from the experimental investigations carried out in the present study and the S-N expressions reported in the literature. Influence of volume fraction of fibers is also incorporated in the S-N expression proposed for estimation of fatigue life of FRC. Hence, from a single expression based on the percentage of fiber volume fraction, fatigue life of FRC can be estimated. Numerical simulations are also carried out on plain concrete and FRC to estimate the fatigue life based on fatigue damage as well as a fracture-mechanics approach. Fatigue life estimated using numerical models adopted in this study correlates well with the experimental results.