Fatigue Behavior of Steel Fiber Concrete in Direct Tension

An investigation was conducted to study the behavior of plain concrete and steel fiber reinforced concrete under direct tension fatigue loading. Tests were conducted on dogbone specimens with varying amounts of steel fiber volume content (0, 0.75, and 1.5%). A new concept was introduced in deriving material damage parameters for plain and steel fiber concrete. The parameters developed were implemented into a damage evolution function to enable the prediction of concrete strength and fatigue secant modulus deterioration of steel fiber reinforced concrete. As such, the damage evolution models developed for steel fiber concrete can be implemented into steel fiber reinforced concrete constitutive models for the analysis of fatigue-damaged concrete elements. From the experimental results, the deformation profiles for plain and steel fiber concrete were similar, and the well-known relationship between the fatigue life and secondary strain rate of concrete in compression also exist for plain concrete and steel fiber concrete in tension. In addition, under the same loading parameters, the fatigue life of steel fiber concrete was found to increase as steel fiber content increased from 0 to 1.5%. (C) 2017 American Society of Civil Engineers.