Tailoring hybrid strain-hardening cementitious composites

A class of fiber-reinforced concrete, commonly called strain-hardening cementitious composite (SHCC), can show very ductile behavior under tension. In the post-cracking stage, several cracks develop before complete failure, which occurs when tensile strains finally localize in one of the formed cracks. To predict the mechanical performances of monofiber SHCC, a cohesive model has been proposed. Such a model is used herein to tailor hybrid SHCC, made with long and short fibers. By combining uniaxial tensile tests and the theoretical results of the model, the critical value of the fibervolume fraction can be evaluated. It should be considered as the minimum amount of long fibers that can lead to the formation of multiple cracking and strain hardening under tensile actions. The aim of the present research is to reduce such volume as much as possible, to improve the workability, and reduce the final cost of SHCC.