Shear slip post-cracking behaviour of polyolefin and steel fibre reinforced concrete

The most significant structural concrete codes consider the shear contribution of fibres in structural design when using fibre reinforced concrete (FRC) if certain requirements are met. However, instead of obtaining such a contribution based on the results of shear tests, the structural codes establish that the parameters used in the structural design be obtained from bending tests. In order to assess the accuracy of such an approach, this study analyses the shear contributions of fibres in FRC by means of shear push-off tests. The influence of two of the most common structural fibres is examined: hooked-end steel and polyolefin fibres. The paper includes the description of the experimental campaign and the push-off tests. In addition, the analysis of the cracking patterns by means of digital image correlation (DIC) is also included. The experimental results are compared with a shear crack opening behaviour model. The significance of the research relies in the comparison of the shear residual capacity of the concrete reinforced with two main types of structural fibres, the cracking patterns and suitability of the shear-friction theory for reproducing the opening-sliding of the crack under push-off testing of FRC. © 2021 Elsevier Lt