Post-cracking tensile behaviour of steel-fibre-reinforced roller-compacted-concrete for FE modelling and design purposes

摘要

Fracture of steel-fibre-reinforced-concrete occurs mostly in the form of a smeared crack bandudundergoing progressive microcracking. For FE modelling and design purposes, this crack band could be characterisedudby a stress-strain (σ-ε) relationship. For industrially-produced steel fibres, existing methodologies suchudas RILEM TC 162-TDF (2003) propose empirical equations to predict a trilinear σ-ε relationship directly fromudbending test results. This paper evaluates the accuracy of these methodologies and their applicability for rollercompacted-concreteudand concrete incorporating steel fibres recycled from post-consumer tyres. It is shown thatudthe energy absorption capacity is generally overestimated by these methodologies, sometimes up to 60%, for bothudconventional and roller-compacted concrete. Tensile behaviour of fibre-reinforced-concrete is estimated in thisudpaper by inverse analysis of bending test results, examining a variety of concrete mixes and steel fibres. A multilinearudrelationship is proposed which largely eliminates the overestimation problem and can lead to safer designs.