A meso-mechanical model for post-cracking tensile constitutive behavior of steel fiber reinforced concrete

Abstract

Steel fiber reinforced concrete (SFRC) with hooked-end steel fiber is extensively used in practical structures due to the excellent post-cracking tensile behavior. And the post-cracking tensile stress of SFRC is directly affected by the pullout behavior of the single fiber and the number of fibers that crossed the crack plane. This study presents a theoretical model to estimate the pullout response of the single hooked-end steel fiber, which considers the plastic deformation of the end-hook, residual friction, spalling of the matrix, and snubbing effect. A simplified model is also presented based on the theoretical model for design purposes. The validity of the theoretical and simplified model is evaluated by the comparisons of the predicted and experimental results. Furthermore, a meso-mechanical tensile constitutive model of SFRC is developed to estimate the post-cracking tensile behavior of SFRC with the contribution of the matrix and the steel fibers are taken into account. Then, a bilinear tensile stress-crack width relationship is put forward considering the effect of the fibers. The contribution of the fibers is related to the fiber inclining angle, the fiber embedded length, the pullout force of the single fiber, and the number of fibers that crossed the crack plane. Finally, it can be found that the proposed model can accurately estimate the post-cracking tensile behavior of SFRC by comparing the estimated results with test data.