An Experimental Study on the Fatigue Failure Mechanisms of Pre–damaged Steel Fibre Reinforced Concrete at a Single Fibre Level

Abstract

In fibre reinforced concrete (FRC), energy is dissipated in the wake of the crack tip through the actions of fibre bridging and fibre pull out. This is the main mechanism which inhibits crack growth, thus increasing the load carrying capacity of FRC by providing post–cracking ductility. Furthermore, the same mechanism is present when FRC undergoes fatigue loading. Typical applications for FRC which undergo significant fatigue loading during their service life include paving applications such as bridge decks, highways and industrial floors. The continuous exposure to cyclic loading results in a decrease in apparent stiffness of the material, which may lead to fatigue failure [1, 2]. Fatigue failures are almost always unexpected, and can have a catastrophic outcome [3, 4]. Thus, the fatigue characteristics become vital performance and design parameters [1]. In this paper, the mechanisms of fatigue failure of pre-damaged hooked-end steel fibre reinforced concrete (SFRC) are investigated at a single fibre level. An initial pre-damage was applied to the fibres before the cyclic loading commenced. The pre–pull out ranged from 0.6 mm to 2.5 mm, and the cyclic loading was applied at 70% and 85% of the maximum static pull out capacity of the fibre embedded in the concrete.