Pullout of inclined fibers from cementitious matrix

Fibers with inclination angles of 0°, 14°, 27°, and 37°, respectively, were pulled out from a cementitious matrix. For each inclination angle, two types of specimens with 16 and eight steel fibers, respectively, were tested. Effects of fiber inclination and number of fibers on peak pullout load and corresponding slip were experimentally examined. Based on failure mechanisms experimentally observed, a fracture mechanics model was developed to predict pullout resistance of aligned and inclined fibers. A rising R-curve is proposed to account for different embedded lengths of fibers. The predicted peak loads match quite well with the experimental results from different studies. The proposed theoretical model can predict reasonably accurately both the peak load as well as the corresponding slip displacement. Predictions are compared with the data for both metallic and synthetic fibers.