Steel fiber-reinforced self-compacting concrete: Experimental research and numerical simulation

Over the last few decades, the astonishing developments of superplasticizers technology allowed great achievements in the conception of concrete mixes exhibiting self-compacting ability. Since the 1980s, some methodologies have been proposed to achieve self-compacting requirements in fresh concrete mixes, based on the evaluation of the flowing properties of these mixes. There still persist, however, some doubts about the most appropriate strategy to define the optimum composition of a self-compacting concrete (SCC) mix, based on a required performance. The behavior of SCC as a structural material can be improved if adequate steel fiber reinforcement is added to SCC mix composition. In fact, the fiber-reinforcement mechanisms can convert the brittle behavior of this cement-based material into a pseudoductile behavior up to a crack width that is acceptable under the structural design point of view. Fiber addition, however, increases the complexity of the mix design process, due to the strong perturbation effect that steel fibers cause on fresh concrete flow. In the present work, a mix design method is proposed to develop cost effective and high performance steel fiber-reinforced self-compacting concrete (SFRSCC). The material properties of the developed SFRSCC are assessed as well as its potentiality as a structural material, carrying out punching and flexural tests on panel prototypes. A material nonlinear analysis is carried out, aiming to address the possibility of calibrating the constitutive model parameters by obtaining, with an inverse analysis, the fracture parameters using force-deflection relationships recorded in simpler laboratory tests, such as the three-point notched beam bending test. The contribution of steel fibers for punching resistance is also discussed.