Tailoring SHCC made of steel cords and plastic fibers

Some Fiber-Reinforced Concrete (FRC), commonly called Strain-Hardening Cement-based Composite (SHCC), can show a very ductile behavior under tensile actions. Specifically, in the post cracking stage, several cracks develop before complete failure, which occurs when tensile strains localize in one of the formed cracks. To better understand the high mechanical performances of SHCC, an analytical model was previously proposed. The model is here used to analyze the strain-hardening behavior of a more cost-effective FRC, made with steel cords and plastic fibers. By combining direct uniaxial tensile tests, performed on dumbbell-shaped specimens, and the theoretical results of the model, the critical value of the fiber volume fraction can be evaluated. It should be considered as the minimum amount of steel cords which can lead to the formation of multiple cracking and strain hardening under tensile actions. The aim of the present paper is to reduce such volume as much as possible, in order to improve the workability and reduce the final cost of SHCC.