Optimization of Steel Fiber-Reinforced Self-Compacting Concrete with Tuff Powder

This study investigates the optimization of the mechanical properties of steel fiber-reinforced self-compacting concrete (SFRSCC) incorporating tuff powder, using the design of experiments (DOE) method. Three parameters were examined: the paste volume (Vp), the steel fiber dosage (% Fib), and the gravel-to-sand ratio (G/S). Eight SFRSCC formulations and a reference concrete (SCCT) with 20 % cement replacement by tuff powder were analyzed. The results indicate that adding steel fibers increases the yield stress and plastic viscosity while slightly reducing compressive strength (up to - 13.13 % at 0.5 % fiber dosage). However, a higher paste volume (+8.5 %) improves compressive strength by 59 %, attributed to the pozzolanic effect of the tuff. Flexural strength benefits from the fiber addition (+45 % between 0.2 % and 0.5 %) and increased paste volume (+26 %). The ductility index rises by 687 % at 0.5 % fiber dosage, with the fibers playing a significant role in stress dissipation. The synergy between tuff and fibers enables the production of high-performance, durable, and cost-effective concrete, leveraging local resources and meeting modern construction requirements while reducing environmental impact.