Blending fibres to enhance the flexural properties of UHPFRC beams
A. B. Sturm, Phillip Visintin, Deric J. Oehlers
Abstract
In this paper, the flexural behaviour of ultra-high performance fibre reinforced concrete (UHPFRC) beams reinforced with macro-, micro- and a blend of macro- and micro-fibres is investigated at all limit states. The goal of this study is to investigate whether the benefits of fibre blending that are observed at a material scale translate to the structural scale. To this end, six UHPFRC beams with two different cross-sections and three different mix designs were tested. Standard codified approaches as well as a segmental analysis technique are then applied to predict the measured load-deflection and load-crack width behaviour of the beams and it is shown that while standard approaches can predict serviceability deflections, the segmental analysis is more accurate when predicting crack width, member ductility and ultimate deformations. Following validation for beams with blended fibres, it is then used as the basis for a parametric study to further investigate the influence of beam geometry and reinforcing details.