A micromechanics-based fatigue dependent fiber-bridging constitutive model

Fiber-reinforced cementitious composites (FRCC) represent a large group of construction and building materials. While numerous experimental studies have been conducted on fatigue of FRCC, predicting FRCC fatigue performance remains difficult. This paper proposes a novel multi-scale analytical model to capture the fatigue dependency of fiber bridging constitutive law in FRCC. On the micro-scale, a new analytical model to predict the post-fatigue single-fiber pullout behavior (P-u curve) is established based on the understanding of the fatigue dependency of fiber and fiber-matrix interface. On the macro-scale, the fatigue-induced fiber strength reduction was considered and probabilistics is introduced to describe the randomness of fiber location and orientation so that the fatigue dependent fiber-bridging constitutive law can be predicted. The model proposed in this paper is the first analytical model that is able to capture the effects of fatigue cycle as well as the fatigue loading level on deterioration of fiber bridging in FRCC.