Assessment of the shear behaviour of polyolefin fibre reinforced concrete and verification by means of digital image correlation

Abstract

Given that remarkable structural applications of fibre reinforced concrete have been successfully developed in the last 60 years, modern concrete codes and fib Model Code have included requirements and formulations for considering the fibre contributions in structural design. In recent times, polyolefin fibre reinforced concrete (PFRC) has been shown as an attractive alternative to steel fibres, with it being chemically stable and having a lower dosage in terms of weight to reach similar residual strengths. It is worth noting that fibre contributions are attained from flexural tensile strengths tests. However, one of the major contributions provided by fibres in rebar substitutions has involved use in replacing shear stirrups. In such a sense, while the use of steel fibres has been shown as effective there is a lack of published literature with regard to PFRC. In this study, push-off tests in specimens obtained from the remaining halves after three-point bending tests have been performed. In addition to the mechanical results obtained, digital image correlation has allowed the cracking processes of the specimens to be identified. This paper offers a significant contribution to the field, given that it relies on the assessment of the shear contributions of polyolefin fibres and comparison with the requirements of the existing codes. Moreover, it supplies notable information about residual shear strengths and the cracking processes that take place.