Numerical modelling of the pull-out of hooked steel fibres from high-strength cementitious matrix, supplemented by experimental results

The paper deals with the numerical modelling of hooked steel fibres embedded in high-strength cementitious matrix. The pull-out of the fibres is first studied by means of accurate three-dimensional models which take into account the non linearities that are present in the physical model. The bonding properties of the fibre–matrix interface considered in the numerical model are based on experimental results of pull-out tests on straight fibres. The results of the numerical model are compared with respect to the results of experimental tests on hooked fibres. Then, the paper studies the effect of different fibre geometries to the load–displacement pull-out curves. It is concluded that fibres having a doubly bended shape have a superior behaviour compared to fibres having a single bended part. Finally, a simplified two-dimensional model is proposed that yield fast results which are similar to the ones obtained by its three-dimensional counterpart.