Flexural Fatigue Behavior of Fiber-reinforced Concrete Based on Dissipated Energy Modeling

After a century of study of fatigue phenomena in concrete, most of the proposed models for predicting the fatigue life of concrete are not sufficiently precise. The traditional models for predicting fatigue life of concrete are only based on the strength-related parameters such as stress level. The high variation of concrete's strength has led to highly scattered fatigue test result and, consequently, reduced the predictive quality of fatigue models. Recently, several studies have focused on incorporation of new damping-related parameters in fatigue life models to improve the predictability of these models. Damping properties have a crucial effect on dynamic motion and energy dissipation capacity in fatigue life, and therefore they seem to be an important factor in characterizing fatigue as a dynamic motion. The general objective of this research was to acquire a comprehensive understanding of the fatigue behavior of concrete in terms of energy dissipation and, consequently, develop a more statistically reliable approach to characterize the fatigue properties of concrete such as fatigue life. To achieve this purpose, damping properties of several concrete mixtures, with or without fiber reinforcement, were studied. A fatigue model based on dissipated energy concept was developed. The new model is then compared to traditional model. The results show that the new fatigue model has better predictive quality than the traditional approach