Optimizing the Dynamic Compressive Behavior of Steel Fiber-Reinforced High-Strength Concrete Through Statistical Analysis and Decision-Making Approaches

This work examines the mechanical performance of steel microfiber-reinforced high-strength concrete (SMFR-HSC) under dynamic compressive loading conditions. For this reason, steel wool micro-fibers with four distinct fiber volume fractions, i.e., 0.0, 0.5, 1.0, and 1.5%, were incorporated into the concrete mixture to assess their influence on dynamic compressive strength ( $$\sigma_{D}$$ ), strain at peak stress ( $$\varepsilon_{p}^{D} )$$ , elastic modulus (E), and energy absorption capacity ( $$EA^{D}$$ ). The SMFR-HSC specimens underwent dynamic testing using a split Hopkinson pressure bar (SHPB) apparatus, complemented by quasi-static tests to assess the effect of fiber content on the dynamic increase factor (DIF). For the dynamic testing, a 25.40 mm diameter SHPB with carefully designed pulse shapers was used to guarantee dynamic stress equilibrium and constant strain rate deformation. The experimental results were analyzed using the two-parameter Weibull distribution to characterize material variability and predict failure probabilities. Following that, the Complex Proportional Assessment (COPRAS) method was used to identify the optimum fiber volume fraction for improved dynamic compressive performance. The findings point out the vital role of optimizing steel fiber volume fraction to improve the dynamic performance of high-strength concrete. Moreover, steel fiber content significantly influences the DIF. Based on the COPRAS method, the SMFR-HSC with a 1.0% fiber volume fraction exhibits the highest performance when exposed to dynamic compressive loading conditions.