Abstract:
It is well-known that the hooked-end steel fiber is one of the most widely-used type of steel fiber in structural engineering, and the pullout behavior of a single steel fiber is significant for determining the tensile constitutive and the tensile toughness of steel fiber reinforced concrete. In order to obtain a theoretical analysis method which can effectively predict the pullout load-end displacement curves of inclined hooked-end steel fiber, the inclined pullout process of the hooked-end steel fiber was divided into three states: fully bonding stage, debonding stage and pullout slipping stage. A novel bond shear stresses-end displacement model was established considering the different steel fiber pullout stages and the damage of the matrix hole. A theoretical analysis model that can predict the load-slip curve of the pullout behavior of inclined hooked-end steel fiber was proposed by considering the plastic deformation of the steel fiber, the additional friction, spalling and snubbing effects of the matrix caused by the fiber pullout inclination. A simplified model was also proposed based on the theoretical model. The existing experimental data were selected to verify and evaluate the proposed calculation model. The results show that the two models proposed in this paper can effectively predict the process of hooked-end steel fiber inclined pullout. And the two models have high calculation accuracy and low coefficient of variation, which provide a theoretical reference for further analysis of the effect of steel fiber on the enhancement of tensile properties of cement-based materials.