A Novel approach for FRC softening law

Abstract

Post peak mechanical behavior of Fiber Reinforced Concrete (FRC) under tensile stress statesdepends not only on the fibers material, shape, content and slenderness but also, on the mechanical and physical properties of the cement paste. Being the improvement of ductility under tension, usually, the main purpose of adding fibers to the concrete composition, an accurate consideration of the resulting post peak behavior results a key parameter for an appropriate numerical simulation of the mechanical behavior of structural FRC elements. In this work, particularly focused on steel FRC, the suitability of cubic Bézier curves is analyzed, firstly, for determining Fracture Energy in mode I of FRC and then, for replacing the traditional exponential decay function usually used for characterizing the softening parameter in concrete constitutive formulations. The results show that the use of these parametric curves allows a flexible numerical approach that can be used for characterizing concretes with very different mechanical behaviors.